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== Install [https://cran.r-project.org/bin/windows/Rtools/ Rtools] for Windows users ==
= Install and upgrade R =
See http://goo.gl/gYh6C for a step-by-step instruction (based on Rtools30.exe) with screenshot. Note that in the step of 'Select Components', the default is 'Package authoring installation'. But we want 'Full installation to build 32 or 64 bit R'; that is, check all components (including tcl/tk) available. The "extra" files will be stored in subdirectories of the R source home directory. These files are not needed to build packages, only to build R itself. By default, the 32-bit R source home is C:\R and 64-bit source home is C:\R64. After the installation, these two directories will contain a new directory 'Tcl'.
[[Install_R|Here]]


My preferred way is not to check the option of setting PATH environment. But I manually add the followings to the PATH environment (based on Rtools v3.2.2)
== New release ==
<pre>
* R 4.4.0
c:\Rtools\bin;
** [https://www.r-bloggers.com/2024/04/whats-new-in-r-4-4-0/ What’s new in R 4.4.0?]
c:\Rtools\gcc-4.6.3\bin;
** [https://www.r-bloggers.com/2024/05/cve-2024-27322-should-never-have-been-assigned-and-r-data-files-are-still-super-risky-even-in-r-4-4-0/ CVE-2024-27322 Should Never Have Been Assigned And R Data Files Are Still Super Risky Even In R 4.4.0], [https://www.ithome.com.tw/news/162626 程式開發語言R爆有程式碼執行漏洞,可用於供應鏈攻擊], [https://www.bleepingcomputer.com/news/security/r-language-flaw-allows-code-execution-via-rds-rdx-files/ R language flaw allows code execution via RDS/RDX files], [https://www.r-bloggers.com/2024/05/a-security-issue-with-r-serialization/ A security issue with R serialization] and the [https://cran.r-project.org/web/packages/RAppArmor/index.html RAppArmor] Package.
C:\Program Files\R\R-3.2.2\bin\i386;
* R 4.3.0
</pre>
** [https://www.jumpingrivers.com/blog/whats-new-r43/ What's new in R 4.3.0?]
** Extracting from a pipe. The underscore _ can be used to refer to the final value from a pipeline <code style="display:inline-block;">mtcars |> lm(mpg ~ disp, data = _) |> _$coef</code>. Previously we need to use [https://stackoverflow.com/a/56038303 this way] or [https://stackoverflow.com/a/60873298 this way]. If we want to apply some (anonymous) function to each element of a list, use '''map(), map_dbl()''' from the [https://purrr.tidyverse.org/ purrr].
* R 4.2.0
** Calling if() or while() with a condition of length greater than one gives an error rather than a warning.
** [https://twitter.com/henrikbengtsson/status/1501306369319735300 use underscore (_) as a placeholder on the right-hand side (RHS) of a forward pipe]. For example, '''mtcars |> subset(cyl == 4) |> lm(mpg ~ disp, data = _) '''
** [https://developer.r-project.org/Blog/public/2022/04/08/enhancements-to-html-documentation/ Enhancements to HTML Documentation]
** [https://www.jumpingrivers.com/blog/new-features-r420/ New features in R 4.2.0]
* R 4.1.0
** [https://developer.r-project.org/blosxom.cgi/R-devel/2021/01/13#n2021-01-13 pipe and shorthand for creating a function]
** [https://www.jumpingrivers.com/blog/new-features-r410-pipe-anonymous-functions/ New features in R 4.1.0] '''anonymous functions''' (lambda function)
* R 4.0.0
** [https://blog.revolutionanalytics.com/2020/04/r-400-is-released.html R 4.0.0 now available, and a look back at R's history]
** [https://www.infoworld.com/article/3540989/major-r-language-update-brings-big-changes.html R 4.0.0 brings numerous and significant changes to syntax, strings, reference counting, grid units, and more], [https://www.infoworld.com/article/3541368/how-to-run-r-40-in-docker-and-3-cool-new-r-40-features.html R 4.0: 3 new features]
**# factor is not default in data frame for character vector
**# palette() function has a new default set of colours, and [[R#New_palette_in_R_4.0.0|palette.colors() & palette.pals()]] are new
**# r"(YourString)" for ''raw'' character constants. See ?Quotes
* R 3.6.0
** [https://blog.revolutionanalytics.com/2019/05/whats-new-in-r-360.html What's new in R 3.6.0]
*** Changes to random number generation
*** More functions now support vectors with more than 2 billion elements
* R 3.5.0
** [https://community.rstudio.com/t/error-listing-packages-error-in-readrds-pfile-cannot-read-workspace-version-3-written-by-r-3-6-0/40570/2 The default serialization format for R changed in May 2018, such that new default format (version 3) for workspaces saved can no longer be read by versions of R older than 3.5]


We can make our life easy by creating a file <Rcommand.bat> with the content (also useful if you have C:\cygwin\bin in your PATH although cygwin setup will not do it automatically for you.)
= Online Editor =
We can run R on web browsers without installing it on local machines (similar to [/ideone.com Ideone.com] for C++. It does not require an account either (cf RStudio).  


PS. I put <Rcommand.bat> under C:\Program Files\R folder. I create a shortcut called 'Rcmd' on desktop. I enter '''C:\Windows\System32\cmd.exe /K "Rcommand.bat"''' in the ''Target'' entry and
== [https://rdrr.io/snippets/ rdrr.io] ==
'''"C:\Program Files\R"''' in ''Start in'' entry.
It can produce graphics too. The package I am testing ([https://www.rdocumentation.org/packages/cobs/versions/1.3-3/topics/cobs cobs]) is available too.
<pre>
@echo off
set PATH=C:\Rtools\bin;c:\Rtools\gcc-4.6.3\bin
set PATH=C:\Program Files\R\R-3.2.2\bin\i386;%PATH%
set PKG_LIBS=`Rscript -e "Rcpp:::LdFlags()"`
set PKG_CPPFLAGS=`Rscript -e "Rcpp:::CxxFlags()"`
echo Setting environment for using R
cmd
</pre>
So we can open the Command Prompt anywhere and run <Rcommand.bat> to get all environment variables ready! On Windows Vista, 7 and 8, we need to run it as administrator. OR we can change the security of the property so the current user can have an executive right.


=== [http://cran.r-project.org/doc/manuals/r-release/R-admin.html#The-Windows-toolset Windows Toolset] ===
== rstudio.cloud ==


Note that R on Windows supports [http://sourceforge.net/projects/mingw-w64/ Mingw-w64] (not Mingw which is a separate project). See [https://stat.ethz.ch/pipermail/r-devel/2013-September/067410.html here] for the issue of developing a Qt application that links against R using Rcpp. And http://qt-project.org/wiki/MinGW is the wiki for compiling Qt using MinGW and MinGW-w64.
== [https://www.rdocumentation.org/ RDocumentation] ==
The interactive engine is based on [https://github.com/datacamp/datacamp-light DataCamp Light]


=== Build R from its source on Windows OS (not cross compile on Linux) ===
For example, [https://www.rdocumentation.org/packages/dplyr/versions/0.5.0/topics/tbl_df tbl_df] function from dplyr package.  
Reference: https://cran.r-project.org/doc/manuals/R-admin.html#Installing-R-under-Windows


First we try to build 32-bit R (tested on R 3.2.2 using Rtools33). At the end I will see how to build a 64-bit R.  
The website [https://cdn.datacamp.com/dcl/standalone-example.html DataCamp] allows to run ''library()'' on the Script window. After that, we can use the packages on ''R Console''.


Download https://www.stats.ox.ac.uk/pub/Rtools/goodies/multilib/local320.zip (read https://www.stats.ox.ac.uk/pub/Rtools/libs.html). create an empty directory, say c:/R/extsoft, and unpack it in that directory by e.g.
[http://documents.datacamp.com/default_r_packages.txt Here] is a list of (common) R packages that users can use on the web.
<pre>
unzip local320.zip -d c:/R/extsoft
</pre>


Tcl: two methods
The packages on RDocumentation may be outdated. For example, the current stringr on CRAN is v1.2.0 (2/18/2017) but RDocumentation has v1.1.0 (8/19/2016).
# Download tcl file from http://www.stats.ox.ac.uk/pub/Rtools/R_Tcl_8-5-8.zip. Unzip and put 'Tcl' into R_HOME folder. 
# If you have chosen a full installation when running Rtools, then copy C:/R/Tcl or C:/R64/Tcl (not the same) to R_HOME folder.


<strike> Open a command prompt as Administrator" </strike>
= Web Applications =
[[R_web|R web applications]]


<pre>
= Creating local repository for CRAN and Bioconductor =
set PATH=c:\Rtools\bin;c:\Rtools\gcc-4.6.3\bin
[[R_repository|R repository]]
set PATH=%PATH%;C:\Users\brb\Downloads\R-3.2.2\bin\i386;c:\windows;c:\windows\system32
set TMPDIR=C:/tmp


tar --no-same-owner -xf R-3.2.2.tar.gz
= Parallel Computing =
cp -R c:\R64\Tcl c:\Users\brb\Downloads\R-3.2.2
See [[R_parallel|R parallel]].


cd R-3.2.2\src\gnuwin32
= Cloud Computing =
cp MkRules.dist MkRules.local
# Modify MkRules.local file; specifically uncomment + change the following 2 flags.
# LOCAL_SOFT = c:/R/extsoft
# EXT_LIBS = $(LOCAL_SOFT)


make
== Install R on Amazon EC2 ==
</pre>
http://randyzwitch.com/r-amazon-ec2/
If we see an error of texi2dvi() complaining pdflatex is not available, it means a vanilla R is successfully built.


If we want to build the recommended packages (MASS, lattice, Matrix, ...) as well, run (check all '''make''' option in <R_HOME\src\gnuwin32\Makefile>)
== Bioconductor on Amazon EC2 ==
<pre>
http://www.bioconductor.org/help/bioconductor-cloud-ami/
make recommended
</pre>


If we need to rebuild R for whatever reason, run
= Big Data Analysis =
<pre>
* [https://cran.r-project.org/web/views/HighPerformanceComputing.html CRAN Task View: High-Performance and Parallel Computing with R]
make clean
* [http://www.xmind.net/m/LKF2/ R for big data] in one picture
</pre>
* [https://rstudio-pubs-static.s3.amazonaws.com/72295_692737b667614d369bd87cb0f51c9a4b.html Handling large data sets in R]
* [https://www.oreilly.com/library/view/big-data-analytics/9781786466457/#toc-start Big Data Analytics with R] by Simon Walkowiak
* [https://pbdr.org/publications.html pbdR]
** https://en.wikipedia.org/wiki/Programming_with_Big_Data_in_R
** [https://olcf.ornl.gov/wp-content/uploads/2016/01/pbdr.pdf Programming with Big Data in R - pbdR] George Ostrouchov and Mike Matheson Oak Ridge National Laboratory


If we want to [http://www.stats.uwo.ca/faculty/murdoch/software/debuggingR/ build R with debug information], run
== bigmemory, biganalytics, bigtabulate ==
<pre>
make DEBUG=T
</pre>


'''NB''': 1. The above works for creating 32-bit R from its source. If we want to build 64-bit R from its source, we need to modify MkRules.local file to turn on the '''MULTI''' flag.
== ff, ffbase ==
<pre>
* tapply does not work. [https://stackoverflow.com/questions/16470677/using-tapply-ave-functions-for-ff-vectors-in-r Using tapply, ave functions for ff vectors in R]
MULTI = 64
* [http://www.bnosac.be/index.php/blog/12-popularity-bigdata-large-data-packages-in-r-and-ffbase-user-presentation Popularity bigdata / large data packages in R and ffbase useR presentation]
</pre>
* [http://www.bnosac.be/images/bnosac/blog/user2013_presentation_ffbase.pdf ffbase: statistical functions for large datasets] in useR 2013
and reset the PATH variable
* [https://www.rdocumentation.org/packages/ffbase/versions/0.12.7/topics/ffbase-package ffbase] package
<pre>
set PATH=c:\Rtools\bin;c:\Rtools\gcc-4.6.3\bin
set PATH=%PATH%;C:\Users\brb\Downloads\R-3.2.2\bin\x64;c:\windows;c:\windows\system32
</pre>
I don't need to mess up with other flags like BINPREF64, M_ARCH, AS_ARCH, RC_ARCH, DT_ARCH or even WIN. The note http://www.stat.yale.edu/~jay/Admin3.3.pdf is kind of old and is not needed. 2. If we have already built 32-bit R and want to continue to build 64-bit R, it is not enough to run 'make clean' before run 'make' again since it will give an error message ''[http://r.789695.n4.nabble.com/compiling-R-for-Windows-64-bit-td4651400.html incompatible ./libR.dll.a when searching for -lR]'' in building Rgraphapp.dll. In fact, libR.dll.a can be cleaned up if we run 'make distclean' but it will also wipe out /bin/i386 folder:(


See also [[R#Create_a_standalone_Rmath_library|Create_a_standalone_Rmath_library]] below about how to create and use a standalone Rmath library in your own C/C++/Fortran program. For example, if you want to know the 95-th percentile of a T distribution or generate a bunch of random variables, you don't need to search internet to find a library; you can just use Rmath library.
== biglm ==


=== Build R from its source on Linux (cross compile) ===
== data.table ==
See [[Tidyverse#data.table|data.table]].


=== Compile and install an R package ===
== disk.frame ==
'''Command line'''
[https://www.brodrigues.co/blog/2019-10-05-parallel_maxlik/ Split-apply-combine for Maximum Likelihood Estimation of a linear model]
<pre>
cd C:\Documents and Settings\brb
wget http://www.bioconductor.org/packages/2.11/bioc/src/contrib/affxparser_1.30.2.tar.gz
C:\progra~1\r\r-2.15.2\bin\R CMD INSTALL --build affxparser_1.30.2.tar.gz
</pre>
'''N.B.''' the ''--build'' is used to create a binary package (i.e. affxparser_1.30.2.zip). In the above example, it will both install the package and create a binary version of the package. If we don't want the binary package, we can ignore the flag.


'''R console'''
== Apache arrow ==
<pre>
* https://arrow.apache.org/docs/r/
install.packages("C:/Users/USERNAME/Downloads/DESeq2paper_1.3.tar.gz", repos=NULL, type="source")
* [https://www.infoworld.com/article/3637038/the-best-open-source-software-of-2021.html#slide17 The best open source software of 2021]
</pre>


See Chapter 6 of [http://cran.r-project.org/doc/manuals/r-release/R-admin.html R Installation and Administration]
= Reproducible Research =
* http://cran.r-project.org/web/views/ReproducibleResearch.html
* [[Reproducible|Reproducible]]


=== Check/Upload to CRAN ===
== Reproducible Environments ==
https://rviews.rstudio.com/2019/04/22/reproducible-environments/


http://win-builder.r-project.org/
== checkpoint package ==
* https://cran.r-project.org/web/packages/checkpoint/index.html
* [https://timogrossenbacher.ch/2017/07/a-truly-reproducible-r-workflow/ A (truly) reproducible R workflow]


=== 64 bit toolchain ===
== Some lessons in R coding ==
See January 2010 email https://stat.ethz.ch/pipermail/r-devel/2010-January/056301.html and [http://cran.r-project.org/doc/manuals/r-patched/R-admin.html#g_t64_002dbit-Windows-builds R-Admin manual].
# don't use rand() and srand() in c. The result is platform dependent. My experience is Ubuntu/Debian/CentOS give the same result but they are different from macOS and Windows. Use [[Rcpp|Rcpp]] package and R's random number generator instead.
# don't use [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/list.files list.files()] directly. The result is platform dependent even different Linux OS. An extra [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/sort sorting] helps!


From R 2.11.0 there is 64 bit Windows binary for R.
= Useful R packages =
* [https://support.rstudio.com/hc/en-us/articles/201057987-Quick-list-of-useful-R-packages Quick list of useful R packages]
* [https://github.com/qinwf/awesome-R awesome-R]
* [https://stevenmortimer.com/one-r-package-a-day/ One R package a day]


== Install R using binary package on Linux OS ==
== Rcpp ==
=== Ubuntu/Debian ===
http://cran.r-project.org/web/packages/Rcpp/index.html. See more [[Rcpp|here]].
<pre>
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E084DAB9
sudo nano /etc/apt/sources.list
# For Ubuntu 14.04 (codename is trusty)
# deb http://cran.rstudio.com/bin/linux/ubuntu trusty/
sudo apt-get update
sudo apt-get install r-base
</pre>


=== Redhat el6 ===
== RInside : embed R in C++ code ==
It should be pretty easy to install via the EPEL: http://fedoraproject.org/wiki/EPEL
* http://dirk.eddelbuettel.com/code/rinside.html
* http://dirk.eddelbuettel.com/papers/rfinance2010_rcpp_rinside_tutorial_handout.pdf


Just follow the instructions to enable the EPEL and then from the CLI as root:
=== Ubuntu ===
With RInside, R can be embedded in a graphical application. For example, $HOME/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/qt directory includes source code of a Qt application to show a kernel density plot with various options like kernel functions, bandwidth and an R command text box to generate the random data. See my demo on [http://www.youtube.com/watch?v=UQ8yKQcPTg0 Youtube]. I have tested this '''qtdensity''' example successfully using Qt 4.8.5.
# Follow the instruction [[#cairoDevice|cairoDevice]] to install required libraries for cairoDevice package and then cairoDevice itself.
# Install [[Qt|Qt]]. Check 'qmake' command becomes available by typing 'whereis qmake' or 'which qmake' in terminal.
# Open Qt Creator from Ubuntu start menu/Launcher. Open the project file $HOME/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/qt/qtdensity.pro in Qt Creator.
# Under Qt Creator, hit 'Ctrl + R' or the big green triangle button on the lower-left corner to build/run the project. If everything works well, you shall see the ''interactive'' program qtdensity appears on your desktop.


yum install R
[[:File:qtdensity.png]]


or via sudo:
With RInside + [http://www.webtoolkit.eu/wt Wt web toolkit] installed, we can also create a web application. To demonstrate the example in ''examples/wt'' directory, we can do
 
sudo yum install R
 
== Install R from source (ix86, x86_64 and arm platforms, Linux system) ==
 
=== Debian system (focus on arm architecture with notes from x86 system) ===
==== Simplest configuration ====
<Method 1 of installing requirements>
 
On my debian system in [[NAS|Pogoplug]] (armv5), [[raspberry|Raspberry Pi]] (armv6) OR [[beaglebone|Beaglebone Black]] & [[Udoo|Udoo]](armv7), I can compile R. See R's [http://cran.r-project.org/doc/manuals/R-admin.html#Installing-R-under-Unix_002dalikes admin manual]. If the OS needs x11, I just need to install 2 required packages.
 
* install gfortran: '''apt-get install build-essential gfortran''' (gfortran is not part of build-essential)
* install readline library: '''apt-get install libreadline5-dev''' (pogoplug), '''apt-get install libreadline6-dev''' (raspberry pi/BBB), '''apt-get install libreadline-dev''' (Ubuntu)
 
Note: if I need X11, I should install
* libX11 and libX11-devel, libXt, libXt-devel (for fedora)
* '''libx11-dev''' (for debian) or '''xorg-dev''' (for pogoplug/raspberry pi/BBB/Odroid debian). See [http://unix.stackexchange.com/questions/14085/x-xorg-and-d-bus-what-is-the-difference here] for the difference of x11 and Xorg.
and optional
* '''texinfo''' (to fix 'WARNING: you cannot build info or HTML versions of the R manuals')
 
<Method 2 of installing requirements (recommended)>
 
Note that it is also safe to install required tools via (please run nano /etc/apt/sources.list to include the repository of your favorite R mirror and also run sudo apt-get update first)
<syntaxhighlight lang='bash'>
sudo apt-get build-dep r-base
</syntaxhighlight>
The above command will install R dependence like jdk, tcl, tex, etc. The ''apt-get build-dep'' gave a more complete list than ''apt-get install r-base-dev'' for some reasons.
 
[Arm architecture] I also run '''apt-get install readline-common'''. I don't know if this is necessary.
If x11 is not needed or not available (eg Pogoplug), I can add '''--with-x=no''' option in ./configure command. If R will be called from other applications such as [[Rserve|Rserve]], I can add '''--enable-R-shlib''' option in ./configure command. Check out ''./configure --help'' to get a complete list of all options.
 
After running
<syntaxhighlight lang='bash'>
wget https://cran.rstudio.com/src/base/R-3/R-3.2.3.tar.gz
tar xzvf R-3.2.3.tar.gz
cd R-3.2.3
./configure --enable-R-shlib
</syntaxhighlight>
('''--enable-R-shlib''' option will create a shared R library '''libR.so''' in $RHOME/lib subdirectory. This allows R to be embedded in other applications. See [[#Embedding_R|Embedding R]].) I got
<pre>
<pre>
R is now configured for armv5tel-unknown-linux-gnueabi
cd ~/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/wt
 
make
  Source directory:          .
sudo ./wtdensity --docroot . --http-address localhost --http-port 8080
  Installation directory:    /usr/local
 
  C compiler:                gcc -std=gnu99  -g -O2
  Fortran 77 compiler:      gfortran  -g -O2
 
  C++ compiler:              g++  -g -O2
  Fortran 90/95 compiler:    gfortran -g -O2
  Obj-C compiler:
 
  Interfaces supported:
  External libraries:        readline
  Additional capabilities:  NLS
  Options enabled:          shared R library, shared BLAS, R profiling
 
  Recommended packages:      yes
 
configure: WARNING: you cannot build info or HTML versions of the R manuals
configure: WARNING: you cannot build PDF versions of the R manuals
configure: WARNING: you cannot build PDF versions of vignettes and help pages
configure: WARNING: I could not determine a browser
configure: WARNING: I could not determine a PDF viewer
</pre>
</pre>
After that, we can run '''make''' to create R binary. If the computer has multiple cores, we can run ''make'' in parallel by using the '''-j''' flag (for example, '-j4' means to run 4 jobs simultaneously). We can also add '''time''' command in front of ''make'' to report the ''make'' time (useful for benchmark).
Then we can go to the browser's address bar and type ''http://localhost:8080'' to see how it works (a screenshot is in [http://dirk.eddelbuettel.com/blog/2011/11/30/ here]).
<syntaxhighlight lang='bash'>
make 
# make -j4
# time make
</syntaxhighlight>


PS 1. On my raspberry pi machine, it shows '''R is now configured for armv6l-unknown-linux-gnueabihf''' and on Beaglebone black it shows '''R is now configured for armv7l-unknown-linux-gnueabihf'''.
=== Windows 7 ===
 
To make RInside works on Windows OS, try the following
PS 2. On my Beaglebone black, it took 2 hours to run 'make', Raspberry Pi 2 took 1 hour, Odroid XU4 took 23 minutes and it only took 5 minutes to run 'make -j 12' on my Xeon W3690 @ 3.47Ghz (6 cores with hyperthread) based on R 3.1.2. The timing is obtained by using 'time' command as described above.
# Make sure R is installed under '''C:\''' instead of '''C:\Program Files''' if we don't want to get an error like ''g++.exe: error: Files/R/R-3.0.1/library/RInside/include: No such file or directory''.
 
# Install RTools
PS 3. On my x86 system, it shows
# Instal RInside package from source (the binary version will give an [http://stackoverflow.com/questions/13137770/fatal-error-unable-to-open-the-base-package error ])
<pre>
# Create a DOS batch file containing necessary paths in PATH environment variable
R is now configured for x86_64-unknown-linux-gnu
<pre>
@echo off
set PATH=C:\Rtools\bin;c:\Rtools\gcc-4.6.3\bin;%PATH%
set PATH=C:\R\R-3.0.1\bin\i386;%PATH%
set PKG_LIBS=`Rscript -e "Rcpp:::LdFlags()"`
set PKG_CPPFLAGS=`Rscript -e "Rcpp:::CxxFlags()"`
set R_HOME=C:\R\R-3.0.1
echo Setting environment for using R
cmd
</pre>
In the Windows command prompt, run
<pre>
cd C:\R\R-3.0.1\library\RInside\examples\standard
make -f Makefile.win
</pre>
Now we can test by running any of executable files that '''make''' generates. For example, ''rinside_sample0''.
<pre>
rinside_sample0
</pre>


  Source directory:         .
As for the Qt application qdensity program, we need to make sure the same version of MinGW was used in building RInside/Rcpp and Qt. See  some discussions in
  Installation directory:   /usr/local
* http://stackoverflow.com/questions/12280707/using-rinside-with-qt-in-windows
* http://www.mail-archive.com/[email protected]/msg04377.html
So the Qt and Wt web tool applications on Windows may or may not be possible.


  C compiler:               gcc -std=gnu99  -g -O2
== GUI ==
  Fortran 77 compiler:       gfortran  -g -O2
=== Qt and R ===
* http://cran.r-project.org/web/packages/qtbase/index.html [https://stat.ethz.ch/pipermail/r-devel/2015-July/071495.html QtDesigner is such a tool, and its output is compatible with the qtbase R package]
* http://qtinterfaces.r-forge.r-project.org


  C++ compiler:              g++  -g -O2
== tkrplot ==
  Fortran 90/95 compiler:    gfortran -g -O2
On Ubuntu, we need to install tk packages, such as by
  Obj-C compiler:
<pre>
 
sudo apt-get install tk-dev
  Interfaces supported:      X11, tcltk
  External libraries:        readline, lzma
  Additional capabilities:  PNG, JPEG, TIFF, NLS, cairo
  Options enabled:          shared R library, shared BLAS, R profiling, Java
 
  Recommended packages:      yes
</pre>
</pre>


[arm] <strike>However, '''make''' gave errors for recommanded packages like KernSmooth, MASS, boot, class, cluster, codetools, foreign, lattice, mgcv, nlme, nnet, rpart, spatial, and survival. The error stems from
== reticulate - Interface to 'Python' ==
'''gcc: SHLIB_LIBADD: No such file or directory'''. Note that I can get this error message even I try '''install.packages("MASS", type="source")'''. A suggested fix is [http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=679180 here]; adding '''perl = TRUE''' in sub() call for two lines in '''src/library/tools/R/install.R''' file. However, I got another error '''shared object 'MASS.so' not found'''. See also http://ftp.debian.org/debian/pool/main/r/r-base/. </strike>To build R without recommended packages like '''./configure --without-recommended'''.
[[Python#R_and_Python:_reticulate_package|Python -> reticulate]]


<pre>
== Hadoop (eg ~100 terabytes) ==
make[1]: Entering directory `/mnt/usb/R-2.15.2/src/library/Recommended'
See also [http://cran.r-project.org/web/views/HighPerformanceComputing.html HighPerformanceComputing]
make[2]: Entering directory `/mnt/usb/R-2.15.2/src/library/Recommended'
begin installing recommended package MASS
* installing *source* package 'MASS' ...
** libs
make[3]: Entering directory `/tmp/Rtmp4caBfg/R.INSTALL1d1244924c77/MASS/src'
gcc -std=gnu99 -I/mnt/usb/R-2.15.2/include -DNDEBUG  -I/usr/local/include    -fpic  -g -O2  -c MASS.c -o MASS.o
gcc -std=gnu99 -I/mnt/usb/R-2.15.2/include -DNDEBUG  -I/usr/local/include    -fpic  -g -O2  -c lqs.c -o lqs.o
gcc -std=gnu99 -shared -L/usr/local/lib -o MASSSHLIB_EXT MASS.o lqs.o SHLIB_LIBADD -L/mnt/usb/R-2.15.2/lib -lR
gcc: SHLIB_LIBADD: No such file or directory
make[3]: *** [MASSSHLIB_EXT] Error 1
make[3]: Leaving directory `/tmp/Rtmp4caBfg/R.INSTALL1d1244924c77/MASS/src'
ERROR: compilation failed for package 'MASS'
* removing '/mnt/usb/R-2.15.2/library/MASS'
make[2]: *** [MASS.ts] Error 1
make[2]: Leaving directory `/mnt/usb/R-2.15.2/src/library/Recommended'
make[1]: *** [recommended-packages] Error 2
make[1]: Leaving directory `/mnt/usb/R-2.15.2/src/library/Recommended'
make: *** [stamp-recommended] Error 2
root@debian:/mnt/usb/R-2.15.2#
root@debian:/mnt/usb/R-2.15.2# bin/R
 
R version 2.15.2 (2012-10-26) -- "Trick or Treat"
Copyright (C) 2012 The R Foundation for Statistical Computing
ISBN 3-900051-07-0
Platform: armv5tel-unknown-linux-gnueabi (32-bit)


R is free software and comes with ABSOLUTELY NO WARRANTY.
* RHadoop
You are welcome to redistribute it under certain conditions.
* Hive
Type 'license()' or 'licence()' for distribution details.
* [http://cran.r-project.org/web/packages/mapReduce/ MapReduce]. Introduction by [http://www.linuxjournal.com/content/introduction-mapreduce-hadoop-linux Linux Journal].
 
* http://www.techspritz.com/category/tutorials/hadoopmapredcue/ Single node or multinode cluster setup using Ubuntu with VirtualBox (Excellent)
R is a collaborative project with many contributors.
* [http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/ Running Hadoop on Ubuntu Linux (Single-Node Cluster)]
Type 'contributors()' for more information and
* Ubuntu 12.04 http://www.youtube.com/watch?v=WN2tJk_oL6E and [https://www.dropbox.com/s/05aurcp42asuktp/Chiu%20Hadoop%20Pig%20Install%20Instructions.docx instruction]
'citation()' on how to cite R or R packages in publications.
* Linux Mint http://blog.hackedexistence.com/installing-hadoop-single-node-on-linux-mint
* http://www.r-bloggers.com/search/hadoop


Type 'demo()' for some demos, 'help()' for on-line help, or
=== [https://github.com/RevolutionAnalytics/RHadoop/wiki RHadoop] ===
'help.start()' for an HTML browser interface to help.
* [http://www.rdatamining.com/tutorials/r-hadoop-setup-guide RDataMining.com] based on Mac.
Type 'q()' to quit R.
* Ubuntu 12.04 - [http://crishantha.com/wp/?p=1414 Crishantha.com], [http://nikhilshah123sh.blogspot.com/2014/03/setting-up-rhadoop-in-ubuntu-1204.html nikhilshah123sh.blogspot.com].[http://bighadoop.wordpress.com/2013/02/25/r-and-hadoop-data-analysis-rhadoop/ Bighadoop.wordpress] contains an example.
* RapReduce in R by [https://github.com/RevolutionAnalytics/rmr2/blob/master/docs/tutorial.md RevolutionAnalytics] with a few examples.
* https://twitter.com/hashtag/rhadoop
* [http://bigd8ta.com/step-by-step-guide-to-setting-up-an-r-hadoop-system/ Bigd8ta.com] based on Ubuntu 14.04.


> library(MASS)
=== Snowdoop: an alternative to MapReduce algorithm ===
Error in library(MASS) : there is no package called 'MASS'
* http://matloff.wordpress.com/2014/11/26/how-about-a-snowdoop-package/
> library()
* http://matloff.wordpress.com/2014/12/26/snowdooppartools-update/comment-page-1/#comment-665
Packages in library '/mnt/usb/R-2.15.2/library':


base                    The R Base Package
== [http://cran.r-project.org/web/packages/XML/index.html XML] ==
compiler                The R Compiler Package
On Ubuntu, we need to install libxml2-dev before we can install XML package.
datasets                The R Datasets Package
<pre>
grDevices              The R Graphics Devices and Support for Colours
sudo apt-get update
                        and Fonts
sudo apt-get install libxml2-dev
graphics                The R Graphics Package
grid                    The Grid Graphics Package
methods                Formal Methods and Classes
parallel                Support for Parallel computation in R
splines                Regression Spline Functions and Classes
stats                  The R Stats Package
stats4                  Statistical Functions using S4 Classes
tcltk                  Tcl/Tk Interface
tools                  Tools for Package Development
utils                  The R Utils Package
> Sys.info()["machine"]
  machine
"armv5tel"
> gc()
        used (Mb) gc trigger (Mb) max used (Mb)
Ncells 170369  4.6    350000  9.4  350000  9.4
Vcells 163228  1.3    905753  7.0  784148  6.0
</pre>
</pre>
See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=679180


PS 4. The complete log of building R from source is in here [[File:Build_R_log.txt‎]]
On CentOS,
 
==== Full configuration ====
<pre>
<pre>
  Interfaces supported:      X11, tcltk
yum -y install libxml2 libxml2-devel
  External libraries:        readline
  Additional capabilities:  PNG, JPEG, TIFF, NLS, cairo
  Options enabled:          shared R library, shared BLAS, R profiling, Java
</pre>
</pre>


==== Update: R 3.0.1 on Beaglebone Black (armv7a) + Ubuntu 13.04 ====
=== XML ===
See the page [[Beaglebone#Build R on BBB|here]].
* http://giventhedata.blogspot.com/2012/06/r-and-web-for-beginners-part-ii-xml-in.html. It gave an example of extracting the XML-values from each XML-tag for all nodes and save them in a data frame using '''xmlSApply()'''.
==== Update: R 3.1.3 & R 3.2.0 on Raspberry Pi 2 ====
* http://www.quantumforest.com/2011/10/reading-html-pages-in-r-for-text-processing/
It took 134m to run 'make -j 4' on RPi 2 using R 3.1.3.  
* https://tonybreyal.wordpress.com/2011/11/18/htmltotext-extracting-text-from-html-via-xpath/
* https://www.tutorialspoint.com/r/r_xml_files.htm
* https://www.datacamp.com/community/tutorials/r-data-import-tutorial#xml
* [http://www.stat.berkeley.edu/~statcur/Workshop2/Presentations/XML.pdf Extracting data from XML] PubMed and Zillow are used to illustrate. xmlTreeParse(),  xmlRoot(),  xmlName() and xmlSApply().
* https://yihui.name/en/2010/10/grabbing-tables-in-webpages-using-the-xml-package/
{{Pre}}
library(XML)


But I got an error when I ran './configure; make -j 4' using R 3.2.0. The errors start from compiling <main/connections.c> file with 'undefined reference to ....'. The gcc version is 4.6.3.
# Read and parse HTML file
doc.html = htmlTreeParse('http://apiolaza.net/babel.html', useInternal = TRUE)


=== Install all dependencies for building R ===
# Extract all the paragraphs (HTML tag is p, starting at
This is a comprehensive list. This list is even larger than r-base-dev.
# the root of the document). Unlist flattens the list to
<syntaxhighlight lang='bash'>
# create a character vector.
root@debian:/mnt/usb/R-2.15.2# apt-get build-dep r-base
doc.text = unlist(xpathApply(doc.html, '//p', xmlValue))
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
  libreadline5-dev
The following NEW packages will be installed:
  bison ca-certificates ca-certificates-java debhelper defoma ed file fontconfig gettext
  gettext-base html2text intltool-debian java-common libaccess-bridge-java
  libaccess-bridge-java-jni libasound2 libasyncns0 libatk1.0-0 libaudit0 libavahi-client3
  libavahi-common-data libavahi-common3 libblas-dev libblas3gf libbz2-dev libcairo2
  libcairo2-dev libcroco3 libcups2 libdatrie1 libdbus-1-3 libexpat1-dev libflac8
  libfontconfig1-dev libfontenc1 libfreetype6-dev libgif4 libglib2.0-dev libgtk2.0-0
  libgtk2.0-common libice-dev libjpeg62-dev libkpathsea5 liblapack-dev liblapack3gf libnewt0.52
  libnspr4-0d libnss3-1d libogg0 libopenjpeg2 libpango1.0-0 libpango1.0-common libpango1.0-dev
  libpcre3-dev libpcrecpp0 libpixman-1-0 libpixman-1-dev libpng12-dev libpoppler5 libpulse0
  libreadline-dev libreadline6-dev libsm-dev libsndfile1 libthai-data libthai0 libtiff4-dev
  libtiffxx0c2 libunistring0 libvorbis0a libvorbisenc2 libxaw7 libxcb-render-util0
  libxcb-render-util0-dev libxcb-render0 libxcb-render0-dev libxcomposite1 libxcursor1
  libxdamage1 libxext-dev libxfixes3 libxfont1 libxft-dev libxi6 libxinerama1 libxkbfile1
  libxmu6 libxmuu1 libxpm4 libxrandr2 libxrender-dev libxss-dev libxt-dev libxtst6 luatex m4
  openjdk-6-jdk openjdk-6-jre openjdk-6-jre-headless openjdk-6-jre-lib openssl pkg-config
  po-debconf preview-latex-style shared-mime-info tcl8.5-dev tex-common texi2html texinfo
  texlive-base texlive-binaries texlive-common texlive-doc-base texlive-extra-utils
  texlive-fonts-recommended texlive-generic-recommended texlive-latex-base texlive-latex-extra
  texlive-latex-recommended texlive-pictures tk8.5-dev tzdata-java whiptail x11-xkb-utils
  x11proto-render-dev x11proto-scrnsaver-dev x11proto-xext-dev xauth xdg-utils xfonts-base
  xfonts-encodings xfonts-utils xkb-data xserver-common xvfb zlib1g-dev
0 upgraded, 136 newly installed, 1 to remove and 0 not upgraded.
Need to get 139 MB of archives.
After this operation, 410 MB of additional disk space will be used.
Do you want to continue [Y/n]?
</syntaxhighlight>


=== Instruction of installing a development version of R under Ubuntu ===
# Replace all by spaces
https://github.com/wch/r-source/wiki  (works on Ubuntu 12.04)
doc.text = gsub('\n', ' ', doc.text)


Note that texi2dvi has to be installed first to avoid the following error. It is better to follow the Ubuntu instruction (https://github.com/wch/r-source/wiki/Ubuntu-build-instructions) when we work on Ubuntu OS.
# Join all the elements of the character vector into a single
<syntaxhighlight lang='bash'>
# character string, separated by spaces
$ (cd doc/manual && make front-matter html-non-svn)
doc.text = paste(doc.text, collapse = ' ')
creating RESOURCES
</pre>
/bin/bash: number-sections: command not found
make: [../../doc/RESOURCES] Error 127 (ignored)
</syntaxhighlight>


To build R, run the following script. To run the built R, type 'bin/R'.
This post http://stackoverflow.com/questions/25315381/using-xpathsapply-to-scrape-xml-attributes-in-r can be used to monitor new releases from github.com.
<pre>
{{Pre}}
# Get recommended packages if necessary
> library(RCurl) # getURL()
tools/rsync-recommended
> library(XML)  # htmlParse and xpathSApply
> xData <- getURL("https://github.com/alexdobin/STAR/releases")
> doc = htmlParse(xData)
> plain.text <- xpathSApply(doc, "//span[@class='css-truncate-target']", xmlValue)
  # I look at the source code and search 2.5.3a and find the tag as
  # <span class="css-truncate-target">2.5.3a</span>
> plain.text
[1] "2.5.3a"      "2.5.2b"      "2.5.2a"      "2.5.1b"      "2.5.1a"   
[6] "2.5.0c"      "2.5.0b"      "STAR_2.5.0a" "STAR_2.4.2a" "STAR_2.4.1d"
>
> # try bwa
> > xData <- getURL("https://github.com/lh3/bwa/releases")
> doc = htmlParse(xData)
> xpathSApply(doc, "//span[@class='css-truncate-target']", xmlValue)
[1] "v0.7.15" "v0.7.13"


R_PAPERSIZE=letter                              \
> # try picard
R_BATCHSAVE="--no-save --no-restore"           \
> xData <- getURL("https://github.com/broadinstitute/picard/releases")
R_BROWSER=xdg-open                              \
> doc = htmlParse(xData)
PAGER=/usr/bin/pager                            \
> xpathSApply(doc, "//span[@class='css-truncate-target']", xmlValue)
PERL=/usr/bin/perl                              \
[1] "2.9.1" "2.9.0" "2.8.3" "2.8.2" "2.8.1" "2.8.0" "2.7.2" "2.7.1" "2.7.0"
R_UNZIPCMD=/usr/bin/unzip                      \
[10] "2.6.0"
R_ZIPCMD=/usr/bin/zip                          \
</pre>
R_PRINTCMD=/usr/bin/lpr                        \
This method can be used to monitor new tags/releases from some projects like [https://github.com/Ultimaker/Cura/releases Cura], BWA, Picard, [https://github.com/alexdobin/STAR/releases STAR]. But for some projects like [https://github.com/ncbi/sra-tools sratools] the '''class''' attribute in the '''span''' element ("css-truncate-target") can be different (such as "tag-name").
LIBnn=lib                                      \
AWK=/usr/bin/awk                                \
CC="ccache gcc"                                 \
CFLAGS="-ggdb -pipe -std=gnu99 -Wall -pedantic" \
CXX="ccache g++"                               \
CXXFLAGS="-ggdb -pipe -Wall -pedantic"         \
FC="ccache gfortran"                           \
F77="ccache gfortran"                           \
MAKE="make"                                     \
./configure                                    \
    --prefix=/usr/local/lib/R-devel            \
    --enable-R-shlib                            \
    --with-blas                                \
    --with-lapack                              \
    --with-readline


#CC="clang -O3"                                  \
=== xmlview ===
#CXX="clang++ -03"                              \
* http://rud.is/b/2016/01/13/cobble-xpath-interactively-with-the-xmlview-package/


== RCurl ==
On Ubuntu, we need to install the packages (the first one is for XML package that RCurl suggests)
{{Pre}}
# Test on Ubuntu 14.04
sudo apt-get install libxml2-dev
sudo apt-get install libcurl4-openssl-dev
</pre>


# Workaround for explicit SVN check introduced by
=== Scrape google scholar results ===
# https://github.com/wch/r-source/commit/4f13e5325dfbcb9fc8f55fc6027af9ae9c7750a3
https://github.com/tonybreyal/Blog-Reference-Functions/blob/master/R/googleScholarXScraper/googleScholarXScraper.R


# Need to build FAQ
No google ID is required
(cd doc/manual && make front-matter html-non-svn)


rm -f non-tarball
Seems not work
<pre>
Error in data.frame(footer = xpathLVApply(doc, xpath.base, "/font/span[@class='gs_fl']",  :
  arguments imply differing number of rows: 2, 0
</pre>


# Get current SVN revsion from git log and save in SVN-REVISION
=== [https://cran.r-project.org/web/packages/devtools/index.html devtools] ===
echo -n 'Revision: ' > SVN-REVISION
'''devtools''' package depends on Curl. It actually depends on some system files. If we just need to install a package, consider the [[#remotes|remotes]] package which was suggested by the [https://cran.r-project.org/web/packages/BiocManager/index.html BiocManager] package.
git log --format=%B -n 1 \
{{Pre}}
  | grep "^git-svn-id" \
# Ubuntu 14.04
  | sed -E 's/^git-svn-id: https:\/\/svn.r-project.org\/R\/.*?@([0-9]+).*$/\1/' \
sudo apt-get install libcurl4-openssl-dev
  >> SVN-REVISION
echo -n 'Last Changed Date: ' >>  SVN-REVISION
git log -1 --pretty=format:"%ad" --date=iso | cut -d' ' -f1 >> SVN-REVISION


# End workaround
# Ubuntu 16.04, 18.04
sudo apt-get install build-essential libcurl4-gnutls-dev libxml2-dev libssl-dev


# Set this to the number of cores on your computer
# Ubuntu 20.04
make --jobs=4
sudo apt-get install -y libxml2-dev libcurl4-openssl-dev libssl-dev
</pre>
</pre>


If we DO NOT use -depth option in git clone command, we can use git checkout SHA1 (40 characters) to get a certain version of code.  
[https://github.com/wch/movies/issues/3 Lazy-load database XXX is corrupt. internal error -3]. It often happens when you use install_github to install a package that's currently loaded; try restarting R and running the app again.
<pre>
 
git checkout f1d91a0b34dbaa6ac807f3852742e3d646fbe95e  # plot(<dendrogram>): Bug 15215 fixed 5/2/2015
NB. According to the output of '''apt-cache show r-cran-devtools''', the binary package is very old though '''apt-cache show r-base''' and [https://cran.r-project.org/bin/linux/ubuntu/#supported-packages supported packages] like ''survival'' shows the latest version.
git checkout trunk                                    # switch back to trunk
 
</pre>
=== [https://github.com/hadley/httr httr] ===
The svn revision number for a certain git revision can be found in the blue box on the github website (git-svn-id). For example, [https://github.com/wch/r-source/commit/f1d91a0b34dbaa6ac807f3852742e3d646fbe95e this revision] has an svn revision number 68302 even the current trunk is 68319.
httr imports curl, jsonlite, mime, openssl and R6 packages.


Now suppose we have run 'git check trunk', create a devel'R successfully. If we want to build R for a certain svn or git revision, we run 'git checkout SHA1', 'make distclean', code to generate the ''SVN-REVISION'' file (it will update this number) and finally './configure' & 'make'.
When I tried to install httr package, I got an error and some message:
<pre>
<pre>
time (./configure --with-recommended-packages=no && make --jobs=5)
Configuration failed because openssl was not found. Try installing:
* deb: libssl-dev (Debian, Ubuntu, etc)
* rpm: openssl-devel (Fedora, CentOS, RHEL)
* csw: libssl_dev (Solaris)
* brew: openssl (Mac OSX)
If openssl is already installed, check that 'pkg-config' is in your
PATH and PKG_CONFIG_PATH contains a openssl.pc file. If pkg-config
is unavailable you can set INCLUDE_DIR and LIB_DIR manually via:
R CMD INSTALL --configure-vars='INCLUDE_DIR=... LIB_DIR=...'
--------------------------------------------------------------------
ERROR: configuration failed for package ‘openssl’
</pre>
</pre>
It turns out after I run '''sudo apt-get install libssl-dev''' in the terminal (Debian), it would go smoothly with installing httr package. Nice httr!


The timing is 4m36s if I skip recommended packages and 7m37s if I don't skip. This is based on Xeon W3690 @ 3.47GHz.
Real example: see [http://stackoverflow.com/questions/27371372/httr-retrieving-data-with-post this post]. Unfortunately I did not get a table result; I only get an html file (R 3.2.5, httr 1.1.0 on Ubuntu and Debian).


The full bash script is available on [https://gist.github.com/arraytools/684a316f09a350a9850f Github Gist].
Since httr package was used in many other packages, take a look at how others use it. For example, [https://github.com/ropensci/aRxiv aRxiv] package.


=== Install multiple versions of R on Ubuntu ===
[https://www.statsandr.com/blog/a-package-to-download-free-springer-books-during-covid-19-quarantine/ A package to download free Springer books during Covid-19 quarantine], [https://www.radmuzom.com/2020/05/03/an-update-to-an-adventure-in-downloading-books/ An update to "An adventure in downloading books"] (rvest package)
* [[R#Instruction_of_installing_a_development_version_of_R_under_Ubuntu|Instruction_of_installing_a_development_version_of_R_under_Ubuntu]]. You can launch the devel version of R using 'RD' command.
* http://stackoverflow.com/questions/24019503/installing-multiple-versions-of-r
* http://r.789695.n4.nabble.com/Installing-different-versions-of-R-simultaneously-on-Linux-td879536.html
* http://stackoverflow.com/questions/8343686/how-to-install-2-different-r-versions-on-debian


To install the devel version of R alongside the current version of R. See [http://sites.psu.edu/theubunturblog/2012/08/09/installing-the-development-version-of-r-on-ubuntu-alongside-the-current-version-of-r/ this post]. For example you need a script that will build r-devel, but install it in a location different from the stable version of R (eg use --prefix=/usr/local/R-X.Y.Z in the ''config'' command). Note that the executable is installed in “/usr/local/lib/R-devel/bin”, but that can be changed to others like "/usr/local/bin".
=== [http://cran.r-project.org/web/packages/curl/ curl] ===
curl is independent of RCurl package.


Another fancy way is to use '''docker'''.
* http://cran.r-project.org/web/packages/curl/vignettes/intro.html
* https://www.opencpu.org/posts/curl-release-0-8/


=== Minimal installation of R from source ===
{{Pre}}
Assume we have installed g++ (or build-essential) and gfortran (Ubuntu has only gcc pre-installed, but not g++),
library(curl)
<pre>
h <- new_handle()
sudo apt-get install build-essential gfortran
handle_setform(h,
</pre>
  name="aaa", email="bbb"
we can go ahead to build a minimal R.
)
<pre>
req <- curl_fetch_memory("http://localhost/d/phpmyql3_scripts/ch02/form2.html", handle = h)
wget http://cran.rstudio.com/src/base/R-3/R-3.1.1.tar.gz
rawToChar(req$content)
tar -xzvf R-3.1.1.tar.gz; cd R-3.1.1
./configure --with-x=no --with-recommended-packages=no --with-readline=no
</pre>
</pre>
See ./configure --help. This still builds the essential packages like base, compiler, datasets, graphics, grDevices, grid, methods, parallel, splines, stats, stats4, tcltk, tools, and utils.


Note that at the end of 'make', it shows an error of 'cannot find any java interpreter. Please make sure java is on your PATH or set JAVA_HOME correspondingly'. Even with the error message, we can use R by typing bin/R.
=== [http://ropensci.org/packages/index.html rOpenSci] packages ===
'''rOpenSci''' contains packages that allow access to data repositories through the R statistical programming environment


To check whether we have Java installed, type 'java -version'.
== [https://cran.r-project.org/web/packages/remotes/index.html remotes] ==
<pre>
Download and install R packages stored in 'GitHub', 'BitBucket', or plain 'subversion' or 'git' repositories. This package is a lightweight replacement of the 'install_*' functions in 'devtools'. Also remotes does not require any extra OS level library (at least on Ubuntu 16.04).
$ java -version
java version "1.6.0_32"
OpenJDK Runtime Environment (IcedTea6 1.13.4) (6b32-1.13.4-4ubuntu0.12.04.2)
OpenJDK 64-Bit Server VM (build 23.25-b01, mixed mode)
</pre>


=== R CMD ===
Example:
* R CMD build someDirectory - create a package
{{Pre}}
* R CMD check somePackage_1.2-3.tar.gz - check a package
# https://github.com/henrikbengtsson/matrixstats
* R CMD INSTALL somePackage_1.2-3.tar.gz - install a package from its source
remotes::install_github('HenrikBengtsson/matrixStats@develop')
 
=== bin/R (shell script) and bin/exec/R (binary executable) on Linux OS ===
'''bin/R''' is just a shell script to launch '''bin/exec/R''' program. So if we try to run the following program
<pre>
# test.R
cat("-- reading arguments\n", sep = "");
cmd_args = commandArgs();
for (arg in cmd_args) cat("  ", arg, "\n", sep="");
</pre>
</pre>
from command line like
<syntaxhighlight lang='bash'>
$ R --slave --no-save --no-restore --no-environ --silent --args arg1=abc < test.R
# OR using Rscript
-- reading arguments
  /home/brb/R-3.0.1/bin/exec/R
  --slave
  --no-save
  --no-restore
  --no-environ
  --silent
  --args
  arg1=abc
</syntaxhighlight>
we can see R actually call '''bin/exec/R''' program.


=== Ubuntu/Debian ===
== DirichletMultinomial ==
Since the R packages '''XML''' & '''RCurl''' are frequently used by other packages (e.g. miniCRAN), it is useful to run the following so the ''install.packages("RCurl")''  and ''install.packages("XML")'' can work without hiccups.
On Ubuntu, we do
<pre>
<pre>
sudo apt-get update
sudo apt-get install libgsl0-dev
sudo apt-get install libxml2-dev
sudo apt-get install libcurl4-openssl-dev
</pre>
</pre>


=== CentOS 6.x ===
== Create GUI ==
Install build-essential (make, gcc, gdb, ...).
=== [http://cran.r-project.org/web/packages/gWidgets/index.html gWidgets] ===
<pre>
su
yum groupinstall "Development Tools"
yum install kernel-devel kernel-headers
</pre>
Install readline and X11 (probably not necessary if we use '''./configure --with-x=no''')
<pre>
yum install readline-devel
yum install libX11 libX11-devel libXt libXt-devel
</pre>
Install libpng (already there) and libpng-devel library. This is for web application purpose because png (and possibly svg) is a standard and preferred graphics format. If we want to output different graphics formats, we have to follow the guide in [http://cran.r-project.org/doc/manuals/R-admin.html#Getting-the-source-files R-admin manual] to install extra graphics libraries in Linux.
<pre>
yum install libpng-devel
rpm -qa | grep "libpng"
# make sure both libpng and libpng-devel exist.
</pre>
Install Java. One possibility is to download from [http://www.oracle.com/technetwork/java/javase/downloads/index.html Oracle]. We want to download jdk-7u45-linux-x64.rpm and jre-7u45-linux-x64.rpm (assume 64-bit OS).
<pre>
rpm -Uvh jdk-7u45-linux-x64.rpm
rpm -Uvh jre-7u45-linux-x64.rpm
# Check
java -version
</pre>
Now we are ready to build R by using "./configure" and then "make" commands.


We can make R accessible from any directory by either run "make install" command or
== [http://cran.r-project.org/web/packages/GenOrd/index.html GenOrd]: Generate ordinal and discrete variables with given correlation matrix and marginal distributions ==
creating an R_HOME environment variable and export it to PATH environment variable, such as
[http://statistical-research.com/simulating-random-multivariate-correlated-data-categorical-variables/?utm_source=rss&utm_medium=rss&utm_campaign=simulating-random-multivariate-correlated-data-categorical-variables here]
<pre>
export R_HOME="path to R"
export PATH=$PATH:$R_HOME/bin
</pre>


== Web Applications ==
== json ==
[[R_web#json|R web -> json]]


See also CRAN Task View: [http://cran.r-project.org/web/views/WebTechnologies.html Web Technologies and Services]
== Map ==
=== [https://rstudio.github.io/leaflet/ leaflet] ===
* rstudio.github.io/leaflet/#installation-and-use
* https://metvurst.wordpress.com/2015/07/24/mapview-basic-interactive-viewing-of-spatial-data-in-r-6/


=== Create HTML5 web and slides using knitr, rmarkdown and pandoc ===
=== choroplethr ===
http://www.gastonsanchez.com/depot/knitr-slides. The HTML5 slides work on my IE 8 too.
* http://blog.revolutionanalytics.com/2014/01/easy-data-maps-with-r-the-choroplethr-package-.html
* http://www.arilamstein.com/blog/2015/06/25/learn-to-map-census-data-in-r/
* http://www.arilamstein.com/blog/2015/09/10/user-question-how-to-add-a-state-border-to-a-zip-code-map/


HTML5 slides examples
=== ggplot2 ===
* http://yihui.name/slides/knitr-slides.html
[https://randomjohn.github.io/r-maps-with-census-data/ How to make maps with Census data in R]
* http://yihui.name/slides/2012-knitr-RStudio.html
* http://yihui.name/slides/2011-r-dev-lessons.html#slide1
* http://inundata.org/R_talks/BARUG/#intro


Software requirement
== [http://cran.r-project.org/web/packages/googleVis/index.html googleVis] ==
* Rstudio
See an example from [[R#RJSONIO|RJSONIO]] above.
* knitr, XML, RCurl (See [http://www.omegahat.org/RCurl/FAQ.html omegahat] or [[R#RCurl|this internal link]] for installation on Ubuntu)
* [http://johnmacfarlane.net/pandoc/ pandoc package] This is a command line tool. I am testing it on Windows 7.


Slide #22 gives an instruction to create
== [https://cran.r-project.org/web/packages/googleAuthR/index.html googleAuthR] ==
* regular html file by using RStudio -> Knit HTML button
Create R functions that interact with OAuth2 Google APIs easily, with auto-refresh and Shiny compatibility.
* HTML5 slides by using pandoc from command line.


Files:
== gtrendsR - Google Trends ==
* Rcmd source: [https://github.com/yihui/knitr-examples/blob/master/009-slides.Rmd 009-slides.Rmd] Note that IE 8 was not supported by github. For IE 9, be sure to turn off "Compatibility View".
* [http://blog.revolutionanalytics.com/2015/12/download-and-plot-google-trends-data-with-r.html Download and plot Google Trends data with R]
* markdown output: 009-slides.md
* [https://datascienceplus.com/analyzing-google-trends-data-in-r/ Analyzing Google Trends Data in R]
* HTML output: 009-slides.html
* [https://trends.google.com/trends/explore?date=2004-01-01%202017-09-04&q=microarray%20analysis microarray analysis] from 2004-04-01
* [https://trends.google.com/trends/explore?date=2004-01-01%202017-09-04&q=ngs%20next%20generation%20sequencing ngs next generation sequencing] from 2004-04-01
* [https://trends.google.com/trends/explore?date=2004-01-01%202017-09-04&q=dna%20sequencing dna sequencing] from 2004-01-01.
* [https://trends.google.com/trends/explore?date=2004-01-01%202017-09-04&q=rna%20sequencing rna sequencing] from 2004-01-01. It can be seen RNA sequencing >> DNA sequencing.
* [http://www.kdnuggets.com/2017/09/python-vs-r-data-science-machine-learning.html?utm_content=buffere1df7&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer Python vs R – Who Is Really Ahead in Data Science, Machine Learning?] and [https://stackoverflow.blog/2017/09/06/incredible-growth-python/ The Incredible Growth of Python] by [https://twitter.com/drob?lang=en David Robinson]


We can create Rcmd source in Rstudio by File -> New -> R Markdown.
== quantmod ==
[http://www.thertrader.com/2015/12/13/maintaining-a-database-of-price-files-in-r/ Maintaining a database of price files in R]. It consists of 3 steps.


There are 4 ways to produce slides with pandoc
# Initial data downloading
* S5
# Update existing data
* DZSlides
# Create a batch file
* Slidy
* Slideous


Use the markdown file (md) and convert it with pandoc
== [http://cran.r-project.org/web/packages/caret/index.html caret] ==
<syntaxhighlight lang='bash'>
* http://topepo.github.io/caret/index.html & https://github.com/topepo/caret/
pandoc -s -S -i -t dzslides --mathjax html5_slides.md -o html5_slides.html
* https://www.r-project.org/conferences/useR-2013/Tutorials/kuhn/user_caret_2up.pdf
</syntaxhighlight>
* https://github.com/cran/caret source code mirrored on github
* Cheatsheet https://www.rstudio.com/resources/cheatsheets/
* [https://daviddalpiaz.github.io/r4sl/the-caret-package.html Chapter 21 of "R for Statistical Learning"]


If we are comfortable with HTML and CSS code, open the html file (generated by pandoc) and modify the CSS style at will.
== Tool for connecting Excel with R ==
* https://bert-toolkit.com/
* [http://www.thertrader.com/2016/11/30/bert-a-newcomer-in-the-r-excel-connection/ BERT: a newcomer in the R Excel connection]
* http://blog.revolutionanalytics.com/2018/08/how-to-use-r-with-excel.html


==== Built-in examples from rmarkdown ====
== write.table ==
<syntaxhighlight lang='rsplus'>
=== Output a named vector ===
# This is done on my ODroid xu4 running Ubuntu Mate 15.10 (Wily)
<pre>
# I used sudo apt-get install pandoc in shell
vec <- c(a = 1, b = 2, c = 3)
# and install.packages("rmarkdown") in R 3.2.3
write.csv(vec, file = "my_file.csv", quote = F)
x = read.csv("my_file.csv", row.names = 1)
vec2 <- x[, 1]
names(vec2) <- rownames(x)
all.equal(vec, vec2)


library(rmarkdown)
# one liner: row names of a 'matrix' become the names of a vector
rmarkdown::render("~/R/armv7l-unknown-linux-gnueabihf-library/3.2/rmarkdown/rmarkdown/templates/html_vignette/skeleton/skeleton.Rmd")
vec3 <- as.matrix(read.csv('my_file.csv', row.names = 1))[, 1]
# the output <skeleton.html> is located under the same dir as <skeleton.Rmd>
all.equal(vec, vec3)
</syntaxhighlight>
</pre>


Note that the image files in the html are embedded '''Base64''' images in the html file. See
=== Avoid leading empty column to header ===
* http://stackoverflow.com/questions/1207190/embedding-base64-images
[https://stackoverflow.com/a/2478624 write.table writes unwanted leading empty column to header when has rownames]
* [https://en.wikipedia.org/wiki/Data_URI_scheme Data URI scheme]
<pre>
* http://www.r-bloggers.com/embed-images-in-rd-documents/
write.table(a, 'a.txt', col.names=NA)
* [https://groups.google.com/forum/#!topic/knitr/NfzCGhZTlu4 How to not embed Base64 images in RMarkdown]
# Or better by
* [http://www.networkx.nl/programming/upload-plots-as-png-file-to-your-wordpress/ Upload plots as PNG file to your wordpress]
write.table(data.frame("SeqId"=rownames(a), a), "a.txt", row.names=FALSE)
 
</pre>
==== Examples ====
Some examples of creating papers (with references) based on knitr can be found on the [http://yihui.name/knitr/demo/showcase/ Papers and reports] section of the knitr website.
* https://github.com/EBI-predocs/knitr-example
* https://github.com/timchurches/meta-analyses
 
====  Read the docs Sphinx theme and journal article formats ====
http://blog.rstudio.org/2016/03/21/r-markdown-custom-formats/
 
* [https://github.com/rstudio/rticles rticles] package
* [https://github.com/juba/rmdformats rmdformats] package
 
==== rmarkdown news ====
* [http://blog.rstudio.org/2016/03/21/rmarkdown-v0-9-5/ floating table of contents and tabbed sections]
 
=== Markdown language ===
 
According to [http://en.wikipedia.org/wiki/Markdown wikipedia]:
 
''Markdown is a lightweight markup language, originally created by John Gruber with substantial contributions from Aaron Swartz, allowing people “to write using an easy-to-read, easy-to-write plain text format, then convert it to structurally valid XHTML (or HTML)”.
''
 
* Markup is a general term for content formatting - such as HTML - but markdown is a library that generates HTML markup.  
 
* [http://stackoverflow.com/editing-help Nice summary from stackoverflow.com] and more complete list from [https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet github].
 
* An example https://gist.github.com/jeromyanglim/2716336
 
* [http://daringfireball.net/projects/markdown/basics basics] and [http://daringfireball.net/projects/markdown/syntax syntax]
 
* Convert mediawiki to markdown using online conversion tool from [http://johnmacfarlane.net/pandoc/try/ pandoc].
 
* [http://support.mashery.com/docs/customizing_your_portal/Markdown_Cheat_Sheet Cheat sheet].
 
* [http://dillinger.io/ Cloud-enabled HTML5 markdown editor]
 
* [http://www.crypti.cc/markdown-here/livedemo.html live demo]
 
* [https://github.com/dgrapov/TeachingDemos/blob/master/Demos/OPLS/OPLS%20example.md Example from hosted in github]
 
* [http://www.rstudio.com/ide/docs/r_markdown R markdown file] and use it in [http://www.rstudio.com/ide/docs/authoring/using_markdown RStudio]. Customizing Chunk Options can be found in [http://yihui.name/knitr/options knitr page] and [http://rpubs.com/gallery/options rpubs.com].
 
=== [http://en.wikipedia.org/wiki/Hypertext_Transfer_Protocol HTTP protocol] ===
 
* http://en.wikipedia.org/wiki/File:Http_request_telnet_ubuntu.png
* [http://en.wikipedia.org/wiki/Query_string Query string]
* How to capture http header? Use '''curl -i en.wikipedia.org'''.
* [http://trac.webkit.org/wiki/WebInspector Web Inspector]. Build-in in Chrome. Right click on any page and choose 'Inspect Element'.
* [http://en.wikipedia.org/wiki/Web_server Web server]
* [http://www.paulgriffiths.net/program/c/webserv.php Simple TCP/IP web server]
* [http://jmarshall.com/easy/http/ HTTP Made Really Easy]
* [http://www.manning.com/hethmon/ Illustrated Guide to HTTP]
* [http://www.ibm.com/developerworks/systems/library/es-nweb/ nweb: a tiny, safe Web server with 200 lines]
* [http://sourceforge.net/projects/tinyhttpd/ Tiny HTTPd]
 
An HTTP server is conceptually simple:
 
# Open port 80 for listening
# When contact is made, gather a little information (get mainly - you can ignore the rest for now)
# Translate the request into a file request
# Open the file and spit it back at the client
 
It gets more difficult depending on how much of HTTP you want to support - POST is a little more complicated, scripts, handling multiple requests, etc.


==== Example in R ====
=== Add blank field AND column names in write.table ===
<syntaxhighlight lang='r'>
* '''write.table'''(, row.names = TRUE) will miss one element on the 1st row when "row.names = TRUE" which is enabled by default.
> co <- socketConnection(port=8080, server=TRUE, blocking=TRUE)
** Suppose x is (n x 2)
> # Now open a web browser and type http://localhost:8080/index.html
** write.table(x, sep="\t") will generate a file with 2 element on the 1st row
> readLines(co,1)
** read.table(file) will return an object with a size (n x 2)
[1] "GET /index.html HTTP/1.1"
** read.delim(file) and read.delim2(file) will also be correct
> readLines(co,1)
* Note that '''write.csv'''() does not have this issue that write.table() has
[1] "Host: localhost:8080"
** Suppose x is (n x 2)
> readLines(co,1)
** Suppose we use write.csv(x, file). The csv file will be ((n+1) x 3) b/c the header row.  
[1] "User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:23.0) Gecko/20100101 Firefox/23.0"
** If we use read.csv(file), the object is (n x 3). So we need to use '''read.csv(file, row.names = 1)'''
> readLines(co,1)
* adding blank field AND column names in write.table(); [https://stackoverflow.com/a/2478624 write.table writes unwanted leading empty column to header when has rownames]
[1] "Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"
:<syntaxhighlight lang="rsplus">
> readLines(co,1)
write.table(a, 'a.txt', col.names=NA)
[1] "Accept-Language: en-US,en;q=0.5"
> readLines(co,1)
[1] "Accept-Encoding: gzip, deflate"
> readLines(co,1)
[1] "Connection: keep-alive"
> readLines(co,1)
[1] ""
</syntaxhighlight>
</syntaxhighlight>
* '''readr::write_tsv'''() does not include row names in the output file


==== Example in C ([http://blog.abhijeetr.com/2010/04/very-simple-http-server-writen-in-c.html Very simple http server written in C], 187 lines) ====
=== read.delim(, row.names=1) and write.table(, row.names=TRUE) ===
[https://www.statology.org/read-delim-in-r/ How to Use read.delim Function in R]


Create a simple hello world html page and save it as <[http://en.wikipedia.org/wiki/List_of_Hello_world_program_examples#H index.html]> in the current directory (/home/brb/Downloads/)
Case 1: no row.names
 
Launch the server program (assume we have done ''gcc http_server.c -o http_server'')
<pre>
<pre>
$ ./http_server -p 50002
write.table(df, 'my_data.txt', quote=FALSE, sep='\t', row.names=FALSE)
Server started at port no. 50002 with root directory as /home/brb/Downloads
my_df <- read.delim('my_data.txt')  # the rownames will be 1, 2, 3, ...
</pre>
</pre>
 
Case 2: with row.names. '''Note:''' if we open the text file in Excel, we'll see the 1st row is missing one header at the end. It is actually missing the column name for the 1st column.
Secondly open a browser and type http://localhost:50002/index.html. The server will respond
<pre>
<pre>
GET /index.html HTTP/1.1
write.table(df, 'my_data.txt', quote=FALSE, sep='\t', row.names=TRUE)
Host: localhost:50002
my_df <- read.delim('my_data.txt') # it will automatically assign the rownames
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:23.0) Gecko/20100101 Firefox/23.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive
 
file: /home/brb/Downloads/index.html
GET /favicon.ico HTTP/1.1
Host: localhost:50002
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:23.0) Gecko/20100101 Firefox/23.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive
 
file: /home/brb/Downloads/favicon.ico
GET /favicon.ico HTTP/1.1
Host: localhost:50003
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:23.0) Gecko/20100101 Firefox/23.0
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive
 
file: /home/brb/Downloads/favicon.ico
</pre>
</pre>
The browser will show the page from <index.html> in server.


The only bad thing is the code does not close the port. For example, if I have use Ctrl+C to close the program and try to re-launch with the same port, it will complain '''socket() or bind(): Address already in use'''.
== Read/Write Excel files package ==
* http://www.milanor.net/blog/?p=779
* [https://www.displayr.com/how-to-read-an-excel-file-into-r/?utm_medium=Feed&utm_source=Syndication flipAPI]. One useful feature of DownloadXLSX, which is not supported by the readxl package, is that it can read Excel files directly from the URL.
* [http://cran.r-project.org/web/packages/xlsx/index.html xlsx]: depends on Java
** [https://stackoverflow.com/a/17976604 Export both Image and Data from R to an Excel spreadsheet]
* [http://cran.r-project.org/web/packages/openxlsx/index.html openxlsx]: not depend on Java. Depend on zip application. On Windows, it seems to be OK without installing Rtools. But it can not read xls file; it works on xlsx file.
** It can't be used to open .xls or .xlm files.
** When I try the package to read an xlsx file, I got a warning: No data found on worksheet. 6/28/2018
** [https://fabiomarroni.wordpress.com/2018/08/07/use-r-to-write-multiple-tables-to-a-single-excel-file/ Use R to write multiple tables to a single Excel file]
* [https://github.com/hadley/readxl readxl]: it does not depend on anything although it can only read but not write Excel files. 
** It is part of tidyverse package. The [https://readxl.tidyverse.org/index.html readxl] website provides several articles for more examples.
** [https://github.com/rstudio/webinars/tree/master/36-readxl readxl webinar].
** One advantage of read_excel (as with read_csv in the readr package) is that the data imports into an easy to print object with three attributes a '''tbl_df''', a '''tbl''' and a '''data.frame.'''
** For writing to Excel formats, use writexl or openxlsx package.
:<syntaxhighlight lang='rsplus'>
library(readxl)
read_excel(path, sheet = NULL, range = NULL, col_names = TRUE,
    col_types = NULL, na = "", trim_ws = TRUE, skip = 0, n_max = Inf,
    guess_max = min(1000, n_max), progress = readxl_progress(),
    .name_repair = "unique")
# Example
read_excel(path, range = cell_cols("c:cx"), col_types = "numeric")
</syntaxhighlight>
* [https://ropensci.org/blog/technotes/2017/09/08/writexl-release writexl]: zero dependency xlsx writer for R
:<syntaxhighlight lang='rsplus'>
library(writexl)
mylst <- list(sheet1name = df1, sheet2name = df2)
write_xlsx(mylst, "output.xlsx")
</syntaxhighlight>


For the Chromosome column, integer values becomes strings (but converted to double, so 5 becomes 5.000000) or NA (empty on sheets).
{{Pre}}
> head(read_excel("~/Downloads/BRCA.xls", 4)[ , -9], 3)
  UniqueID (Double-click) CloneID UGCluster
1                  HK1A1  21652 Hs.445981
2                  HK1A2  22012 Hs.119177
3                  HK1A4  22293 Hs.501376
                                                    Name Symbol EntrezID
1 Catenin (cadherin-associated protein), alpha 1, 102kDa CTNNA1    1495
2                              ADP-ribosylation factor 3  ARF3      377
3                          Uroporphyrinogen III synthase  UROS    7390
  Chromosome      Cytoband ChimericClusterIDs Filter
1  5.000000        5q31.2              <NA>      1
2  12.000000        12q13              <NA>      1
3      <NA> 10q25.2-q26.3              <NA>      1
</pre>


==== Another Example in C (55 lines) ====
The hidden worksheets become visible (Not sure what are those first rows mean in the output).
http://mwaidyanatha.blogspot.com/2011/05/writing-simple-web-server-in-c.html
{{Pre}}
> excel_sheets("~/Downloads/BRCA.xls")
DEFINEDNAME: 21 00 00 01 0b 00 00 00 02 00 00 00 00 00 00 0d 3b 01 00 00 00 9a 0c 00 00 1a 00
DEFINEDNAME: 21 00 00 01 0b 00 00 00 04 00 00 00 00 00 00 0d 3b 03 00 00 00 9b 0c 00 00 0a 00
DEFINEDNAME: 21 00 00 01 0b 00 00 00 03 00 00 00 00 00 00 0d 3b 02 00 00 00 9a 0c 00 00 06 00
[1] "Experiment descriptors" "Filtered log ratio"    "Gene identifiers"     
[4] "Gene annotations"      "CollateInfo"            "GeneSubsets"         
[7] "GeneSubsetsTemp"     
</pre>


The response is embedded in the C code.
The Chinese character works too.
{{Pre}}
> read_excel("~/Downloads/testChinese.xlsx", 1)
  中文 B C
1    a b c
2    1 2 3
</pre>


If we test the server program by opening a browser and type "http://localhost:15000/", the server received the follwing 7 lines
To read all worksheets we need a convenient function
<pre>
{{Pre}}
GET / HTTP/1.1
read_excel_allsheets <- function(filename) {
Host: localhost:15000
    sheets <- readxl::excel_sheets(filename)
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:23.0) Gecko/20100101 Firefox/23.0
    sheets <- sheets[-1] # Skip sheet 1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
    x <- lapply(sheets, function(X) readxl::read_excel(filename, sheet = X, col_types = "numeric"))
Accept-Language: en-US,en;q=0.5
    names(x) <- sheets
Accept-Encoding: gzip, deflate
    x
Connection: keep-alive
}
dcfile <- "table0.77_dC_biospear.xlsx"
dc <- read_excel_allsheets(dcfile)
# Each component (eg dc[[1]]) is a tibble.
</pre>
</pre>


If we include a non-executable file's name in the url, we will be able to download that file. Try "http://localhost:15000/client.c".
=== [https://cran.r-project.org/web/packages/readr/ readr] ===


If we use telnet program to test, wee need to type anything we want
Compared to base equivalents like '''read.csv()''', '''readr''' is much faster and gives more convenient output: it never converts strings to factors, can parse date/times, and it doesn’t munge the column names.
<pre>
$ telnet localhost 15000
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
ThisCanBeAnything        <=== This is what I typed in the client and it is also shown on server
HTTP/1.1 200 OK          <=== From here is what I got from server
Content-length: 37Content-Type: text/html


HTML_DATA_HERE_AS_YOU_MENTIONED_ABOVE <=== The html tags are not passed from server, interesting!
[https://blog.rstudio.org/2016/08/05/readr-1-0-0/ 1.0.0] released. [https://www.tidyverse.org/blog/2021/07/readr-2-0-0/ readr 2.0.0] adds built-in support for reading multiple files at once, fast multi-threaded lazy reading and automatic guessing of delimiters among other changes.
Connection closed by foreign host.
$
</pre>


See also more examples under [[C#Socket_Programming_Examples_using_C.2FC.2B.2B.2FQt|C page]].
Consider a [http://www.cs.utoronto.ca/~juris/data/cmapbatch/instmatx.21.txt text file] where the table (6100 x 22) has duplicated row names and the (1,1) element is empty. The column names are all unique.
* read.delim() will treat the first column as rownames but it does not allow duplicated row names. Even we use row.names=NULL, it still does not read correctly. It does give warnings (EOF within quoted string & number of items read is not a multiple of the number of columns). The dim is 5177 x 22.
* readr::read_delim(Filename, "\t") will miss the last column. The dim is 6100 x 21.
* '''data.table::fread(Filename, sep = "\t")''' will detect the number of column names is less than the number of columns. Added 1 extra default column name for the first column which is guessed to be row names or an index. The dim is 6100 x 22. (Winner!)


==== Others  ====
The '''readr::read_csv()''' function is as fast as '''data.table::fread()''' function. ''For files beyond 100MB in size fread() and read_csv() can be expected to be around 5 times faster than read.csv().'' See 5.3 of Efficient R Programming book.
* http://rosettacode.org/wiki/Hello_world/ (Different languages)
* http://kperisetla.blogspot.com/2012/07/simple-http-web-server-in-c.html (Windows web server)
* http://css.dzone.com/articles/web-server-c (handling HTTP GET request, handling content types(txt, html, jpg, zip. rar, pdf, php etc.), sending proper HTTP error codes, serving the files from a web root, change in web root in a config file, zero copy optimization using sendfile method and php file handling.)
* https://github.com/gtungatkar/Simple-HTTP-server
* https://github.com/davidmoreno/onion


=== [http://www.rstudio.com/shiny/ shiny] ===
Note that '''data.table::fread()''' can read a selection of the columns.
The following is what we see on a browser after we run an example from shiny package. See http://rstudio.github.com/shiny/tutorial/#hello-shiny. Note that the R session needs to be on; i.e. R command prompt will not be returned unless we press Ctrl+C or ESC.


[[File:ShinyHello.png|100px]]
=== Speed comparison ===
[[File:Shinympg.png|100px]]
[https://predictivehacks.com/the-fastest-way-to-read-and-write-file-in-r/ The Fastest Way To Read And Write Files In R]. data.table >> readr >> base.
[[File:ShinyReactivity.png|100px]]
[[File:ShinyTabsets.png|100px]]
[[File:ShinyUpload.png|100px]]


shiny depends on [http://cran.r-project.org/web/packages/websockets/index.html websockets], caTools, bitops, digest packages.
== [http://cran.r-project.org/web/packages/ggplot2/index.html ggplot2] ==
See [[Ggplot2|ggplot2]]


Q & A:
== Data Manipulation & Tidyverse ==
* Q: If we run ''runExample('01_hello')'' in Rserve from an R client, we can continue our work in R client without losing the functionality of the GUI from shiny. Question: how do we kill the job?
See [[Tidyverse|Tidyverse]].
* If I run the example "01_hello", the browser only shows the control but not graph on Firefox? A: Use Chrome or Opera as the default browser.
* If I run the example "01_hello" on RHEL the first time, it works fine. But if I click 'Ctrl + C' to stop it and run it again, I got a message
<pre>
Warning in .SOCK_SERVE(port) : R-Websockets(tcpserv): bind() failed.
Error in createContext(port, webpage, is.binary = is.binary) :
  Unable to bind socket on port 8100; is it realsy in use?
</pre>
A simple solution is to close R and open it again.
* Q: Deployment on web. A: Not ready yet. Shiny server platform is still under beta testing. Shiny apps are hosted using the R websockets package which acts more like a tcp server than a web server, and that architecture just doesn't fit with rApache, or even apache for that matter.


* Q: How difficult to put the code in Gist:github? A: Just create an account. Do not even need to create a repository. Just go to http://gist.github.com and create a new gist. The new gist can be secret or public. A secret gist can not be edited again after it is created although it works fine when it was used in runGist() function.
== Data Science ==
See [[Data_science|Data science]] page


==== Deploy to run locally ====
== microbenchmark & rbenchmark ==
Follow the instruction [http://rstudio.github.io/shiny/tutorial/#run-and-debug here], we can do as following (Tested on Windows OS)
* [https://cran.r-project.org/web/packages/microbenchmark/index.html microbenchmark]
# Create a desktop shortcut with target '''"C:\Program Files\R\R-3.0.2\bin\R.exe" -e "shiny::runExample('01_hello')" '''. We can name the shortcut as we like, e.g. '''R+shiny'''
** [https://www.r-bloggers.com/using-the-microbenchmark-package-to-compare-the-execution-time-of-r-expressions/ Using the microbenchmark package to compare the execution time of R expressions]
# Double click the shortcut. The Windows Firewall will be popped up and say it block some features of the program. It does not matter if we choose Allow access or Cancel.
* [https://cran.r-project.org/web/packages/rbenchmark/index.html rbenchmark] (not updated since 2012)
# Look at the command prompt window (black background console window), it will say something like <pre>Listening on port 7510</pre> at the last line of the console.
# Open your browser (Chrome or Firefox works), and type the address '''http://localhost:7510'''. You will see something magic happen.
# If we don't want to play with it, we can close the browser and close the command console (hit 'x')too.


==== Deploy on shinyapps.io ====
== Plot, image ==
See [http://shiny.rstudio.com/articles/shinyapps.html Getting started with shinyapps.io] page.
=== [http://cran.r-project.org/web/packages/jpeg/index.html jpeg] ===
If we want to create the image on this wiki left hand side panel, we can use the '''jpeg''' package to read an existing plot and then edit and save it.


Shinyapps.io can accept google account to sign up. I create an account and a test application/instance on
We can also use the jpeg package to import and manipulate a jpg image. See [http://moderndata.plot.ly/fun-with-heatmaps-and-plotly/ Fun with Heatmaps and Plotly].


https://taichimd.shinyapps.io/testshiny/
=== EPS/postscript format ===
<ul>
<li>Don't use postscript().  


==== Deploy to run remotely -shiny server ====
<li>Use cairo_ps(). See [http://www.sthda.com/english/wiki/saving-high-resolution-ggplots-how-to-preserve-semi-transparency aving High-Resolution ggplots: How to Preserve Semi-Transparency]. It works on base R plots too.
If we want to deploy our shiny apps to WWW, we need to install [https://github.com/rstudio/shiny-server shiny server].
<syntaxhighlight lang='r'>
cairo_ps(filename = "survival-curves.eps",
        width = 7, height = 7, pointsize = 12,
        fallback_resolution = 300)
print(p) # or any base R plots statements
dev.off()
</syntaxhighlight>


Following the guide on [http://www.rstudio.com/shiny/server/ here], shiny-server is up smoothly on my Ubuntu machine. After I run the command '''sudo gdebi shiny-server-0.4.0.8-amd64.deb''', shiny-server is started. Thanks to '''upstart''' in Ubuntu, shiny-server is automatically started whenever the machine is started.
<li>[https://stackoverflow.com/a/8147482 Export a graph to .eps file with R].  
* The results looks the same as using cairo_ps().
* The file size by setEPS() + postscript() is quite smaller compared to using cairo_ps().
* However, '''grep''' can find the characters shown on the plot generated by cairo_ps() but not setEPS() + postscript().
<pre>
setEPS()
postscript("whatever.eps") # 483 KB
plot(rnorm(20000))
dev.off()
# grep rnorm whatever.eps # Not found!


Each app directory needs to be copied to '''/srv/shiny-server/''' (which links to '''/opt/shiny-server/''') directory using sudo.  
cairo_ps("whatever_cairo.eps")  # 2.4 MB
plot(rnorm(20000))
dev.off()
# grep rnorm whatever_cairo.eps  # Found!
</pre>


The default port is 3838. That is, the remote computer can access the website using http://xxx.xxx.x.xx:3838/AppName.
<li> View EPS files
* Linux: evince. It is installed by default.
* Mac: evince. ''' brew install evince'''
* Windows. Install '''ghostscript''' [https://www.npackd.org/p/com.ghostscript.Ghostscript64/9.20 9.20] (10.x does not work with ghostview/GSview) and '''ghostview/GSview''' (5.0). In Ghostview, open Options -> Advanced Configure. Change '''Ghostscript DLL''' path AND '''Ghostscript include Path''' according to the ghostscript location ("C:\.


Last but not the least, according to its web page, shiny-server is '''Experimental quality. Use at your own risk!'''.
<li>Edit EPS files: Inkscape
* Step 1: open the EPS file
* Step 2: EPS Input: Determine page orientation from text direction 'Page by page' - OK
* Step 3: PDF Import Settings: default is "Internal import", but we shall choose '''"Cairo import"'''.
* Step 4: '''Zoom in''' first.  
* Step 5: Click on '''Layers and Objects''' tab on the RHS. Now we can select any lines or letters and edit them as we like. The selected objects are highlighted in the "Layers and Objects" panel. That is, we can select multiple objects using object names. The selected objects can be rotated (Object -> Rotate 90 CW), for example.
* Step 6: We can save the plot as any formats like svg, eps, pdf, html, pdf, ...
</ul>


==== Shiny https: Securing Shiny Open Source with SSL ====
=== png and resolution ===
http://ipub.com/shiny-https/
It seems people use '''res=300''' as a definition of high resolution.  


==== Deploy your own shiny server ====
<ul>
* http://qualityandinnovation.com/2015/12/09/deploying-your-very-own-shiny-server/
<li>Bottom line: fix res=300 and adjust height/width as needed. The default is res=72, height=width=480. If we increase res=300, the text font size will be increased, lines become thicker and the plot looks like a zoom-in.
<li>[https://stackoverflow.com/a/51194014 Saving high resolution plot in png].
<pre>
png("heatmap.png", width = 8, height = 6, units='in', res = 300)
# we can adjust width/height as we like
# the pixel values will be width=8*300 and height=6*300 which is equivalent to
# 8*300 * 6*300/10^6 = 4.32 Megapixels (1M pixels = 10^6 pixels) in camera's term
# However, if we use png(, width=8*300, height=6*300, units='px'), it will produce
# a plot with very large figure body and tiny text font size.


==== Shiny + Docker ====
# It seems the following command gives the same result as above
See [http://www.flaviobarros.net/2015/08/10/share-your-shiny-apps-with-docker-and-kitematic/ this post]. It uses the gui of Docker called '''[https://kitematic.com/ Kitematic]'''.
png("heatmap.png", width = 8*300, height = 6*300, res = 300) # default units="px"
</pre>
<li>Chapter 14.5 [https://r-graphics.org/recipe-output-bitmap Outputting to Bitmap (PNG/TIFF) Files] by R Graphics Cookbook
* Changing the resolution affects the size (in pixels) of graphical objects like text, lines, and points.
<li>[https://blog.revolutionanalytics.com/2009/01/10-tips-for-making-your-r-graphics-look-their-best.html 10 tips for making your R graphics look their best] David Smith
* In Word you can resize the graphic to an appropriate size, but the high resolution gives you the flexibility to choose a size while not compromising on the quality.  I'd recommend '''at least 1200 pixels''' on the longest side for standard printers.
<li>[https://stat.ethz.ch/R-manual/R-devel/library/grDevices/html/png.html ?png]. The png function has default settings ppi=72, height=480, width=480, units="px".
* By default no resolution is recorded in the file, except for BMP.
* [https://www.adobe.com/creativecloud/file-types/image/comparison/bmp-vs-png.html BMP vs PNG format]. If you need a smaller file size and don’t mind a lossless compression, PNG might be a better choice. If you need to retain as much detail as possible and don’t mind a larger file size, BMP could be the way to go.
** '''Compression''': BMP files are raw and uncompressed, meaning they’re large files that retain as much detail as possible. On the other hand, PNG files are compressed but still lossless. This means you can reduce or expand PNGs without losing any information.
** '''File size''': BMPs are larger than PNGs. This is because PNG files automatically compress, and can be compressed again to make the file even smaller.
** '''Common uses''': BMP contains a maximum amount of details while PNGs are good for small illustrations, sketches, drawings, logos and icons.
** '''Quality''': No difference
** '''Transparency''': PNG supports transparency while BMP doesn't
<li>Some comparison about the ratio
* 11/8.5=1.29  (A4 paper)
* 8/6=1.33    (plot output)
* 1440/900=1.6 (my display)
<li>[https://babichmorrowc.github.io/post/2019-05-23-highres-figures/ Setting resolution and aspect ratios in R]
<li>The difference of '''res''' parameter for a simple plot. [https://www.tutorialspoint.com/how-to-change-the-resolution-of-a-plot-in-base-r How to change the resolution of a plot in base R?]
<li>[https://danieljhocking.wordpress.com/2013/03/12/high-resolution-figures-in-r/ High Resolution Figures in R].
<li>[https://magesblog.com/post/2013-10-29-high-resolution-graphics-with-r/ High resolution graphics with R]
<li>[https://stackoverflow.com/questions/8399100/r-plot-size-and-resolution R plot: size and resolution]
<li>[https://stackoverflow.com/a/22815896 How can I increase the resolution of my plot in R?], [https://cran.r-project.org/web/packages/devEMF/index.html devEMF] package
<li>See [[Images#Anti-alias_%E4%BF%AE%E9%82%8A|Images -> Anti-alias]].
<li>How to check DPI on PNG
* '''The width of a PNG file in terms of inches cannot be determined directly from the file itself''', as the file contains pixel dimensions, not physical dimensions. However, '''you can calculate the width in inches if you know the resolution (DPI, dots per inch) of the image'''. Remember that converting pixel measurements to physical measurements like inches involves a specific resolution (DPI), and different devices may display the same image at different sizes due to having different resolutions.
<li>[https://community.rstudio.com/t/save-high-resolution-figures-from-r-300dpi/62016/3 Cairo] case.
</ul>


==== [http://rstudio.github.io/shinydashboard/ shinydashboard] ====
=== PowerPoint ===
<ul>
<li>For PP presentation, I found it is useful to use svg() to generate a small size figure. Then when we enlarge the plot, the text font size can be enlarged too. According to [https://www.rdocumentation.org/packages/grDevices/versions/3.6.2/topics/cairo svg], by default, width = 7, height = 7, pointsize = 12, family = '''sans'''.
<li>Try the following code. The font size is the same for both plots/files. However, the first plot can be enlarged without losing its quality.
<pre>
svg("svg4.svg", width=4, height=4)
plot(1:10, main="width=4, height=4")
dev.off()


==== shinytheme ====
svg("svg7.svg", width=7, height=7) # default
[https://blog.rstudio.org/2016/10/13/shinythemes-1-1-1/ shinythemes 1.1.1]
plot(1:10, main="width=7, height=7")
dev.off()
</pre>
</ul>


==== [http://www.shinyapps.io/ shinyapps.io] ====
=== magick ===
http://www.rstudio.com/products/shinyapps/
https://cran.r-project.org/web/packages/magick/


==== websocket ====
See an example [[:File:Progpreg.png|here]] I created.
http://illposed.net/jsm2012.pdf


==== CentOS ====
=== [http://cran.r-project.org/web/packages/Cairo/index.html Cairo] ===
http://blog.supstat.com/2014/05/install-rstudio-server-on-centos6-5/
See [[Heatmap#White_strips_.28artifacts.29|White strips problem]] in png() or tiff().


==== Gallery ====
=== geDevices ===
* http://www.showmeshiny.com/
* [https://www.jumpingrivers.com/blog/r-graphics-cairo-png-pdf-saving/ Saving R Graphics across OSs]. Use png(type="cairo-png") or the [https://cran.r-project.org/web/packages/ragg/index.html ragg] package which can be incorporated into RStudio.
* Example of using googleVis: http://shinyeoda.cloudapp.net/
* [https://www.jumpingrivers.com/blog/r-knitr-markdown-png-pdf-graphics/ Setting the Graphics Device in a RMarkdown Document]
* Integrate with Javascript: https://github.com/wch/shiny-jsdemo and https://github.com/trestletech/ShinyDash-Sample
* interactiveDisplay (Bioconductor package, there is a STOP Application button too): http://www.bioconductor.org/packages/release/bioc/html/interactiveDisplay.html


==== Persistent data storage in Shiny apps ====
=== [https://cran.r-project.org/web/packages/cairoDevice/ cairoDevice] ===
http://deanattali.com/blog/shiny-persistent-data-storage/
PS. Not sure the advantage of functions in this package compared to R's functions (eg. Cairo_svg() vs svg()).


==== Password protection ====
For ubuntu OS, we need to install 2 libraries and 1 R package '''RGtk2'''.
* http://ipub.com/shiny-password-protect/
<pre>
sudo apt-get install libgtk2.0-dev libcairo2-dev
</pre>


==== Install all required R packages ====
On Windows OS, we may got the error: '''unable to load shared object 'C:/Program Files/R/R-3.0.2/library/cairoDevice/libs/x64/cairoDevice.dll' '''. We need to follow the instruction in [http://tolstoy.newcastle.edu.au/R/e6/help/09/05/15613.html here].
http://padamson.github.io/r/shiny/2016/03/13/install-required-r-packages.html


==== Tips ====
=== dpi requirement for publication ===
[http://deanattali.com/blog/advanced-shiny-tips/ Shiny tips & tricks for improving your apps and solving common problems] by Dean Attali.
[http://www.cookbook-r.com/Graphs/Output_to_a_file/ For import into PDF-incapable programs (MS Office)]


=== Docker ===
=== sketcher: photo to sketch effects ===
* [https://blog.ouseful.info/2016/05/03/using-docker-as-a-personal-productvity-tool-running-command-line-apps/ Using Docker as a Personal Productivity Tool – Running Command Line Apps Bundled in Docker Containers]
https://htsuda.net/sketcher/
* Mark McCahill (RStudio + Docker)
** http://sites.duke.edu/researchcomputing/files/2014/09/mccahill-DockerDays.pdf
** https://github.com/mccahill/docker-rstudio
** https://hub.docker.com/r/mccahill/rstudio/~/dockerfile/


=== [http://cran.r-project.org/web/packages/httpuv/index.html httpuv] ===
=== httpgd ===
http and WebSocket library.
* https://nx10.github.io/httpgd/ A graphics device for R that is accessible via network protocols. Display graphics on browsers.
* [https://youtu.be/uxyhmhRVOfw Three tricks to make IDEs other than Rstudio better for R development]


=== [http://rapache.net/ RApache] ===
== [http://igraph.org/r/ igraph] ==
[[R_web#igraph|R web -> igraph]]


=== [http://cran.r-project.org/web/packages/gWidgetsWWW/index.html gWidgetsWWW] ===
== Identifying dependencies of R functions and scripts ==
https://stackoverflow.com/questions/8761857/identifying-dependencies-of-r-functions-and-scripts
{{Pre}}
library(mvbutils)
foodweb(where = "package:batr")


* http://www.jstatsoft.org/v49/i10/paper
foodweb( find.funs("package:batr"), prune="survRiskPredict", lwd=2)
* [https://github.com/jverzani/gWidgetsWWW2 gWidgetsWWW2] gWidgetsWWW based on Rook
* [http://www.r-statistics.com/2012/11/comparing-shiny-with-gwidgetswww2-rapache/ Compare shiny with gWidgetsWWW2.rapache]


=== [http://cran.r-project.org/web/packages/Rook/index.html Rook] ===
foodweb( find.funs("package:batr"), prune="classPredict", lwd=2)
</pre>


Since R 2.13, the internal web server was exposed.
== [http://cran.r-project.org/web/packages/iterators/ iterators] ==
Iterator is useful over for-loop if the data is already a '''collection'''. It can be used to iterate over a vector, data frame, matrix, file


[https://docs.google.com/present/view?id=0AUTe_sntp1JtZGdnbjVicTlfMzFuZDQ5dmJxNw Tutorual from useR2012] and [https://github.com/rstats/RookTutorial Jeffrey Horner]
Iterator can be combined to use with foreach package http://www.exegetic.biz/blog/2013/11/iterators-in-r/ has more elaboration.


Here is another [http://www.rinfinance.com/agenda/2011/JeffHorner.pdf one] from http://www.rinfinance.com.
== Colors ==
 
* [https://scales.r-lib.org/ scales] package. This is used in ggplot2 package.
Rook is also supported by [rApache too. See http://rapache.net/manual.html.
<ul>
 
<li>[https://cran.r-project.org/web/packages/colorspace/index.html colorspace]: A Toolbox for Manipulating and Assessing Colors and Palettes. Popular! Many reverse imports/suggests; e.g. ComplexHeatmap. See my [[Ggplot2#colorspace_package|ggplot2]] page.
Google group. https://groups.google.com/forum/?fromgroups#!forum/rrook
<pre>
hcl_palettes(plot = TRUE) # a quick overview
hcl_palettes(palette = "Dark 2", n=5, plot = T)
q4 <- qualitative_hcl(4, palette = "Dark 3")
</pre>
</ul>
* [https://statisticsglobe.com/create-color-range-between-two-colors-in-r Create color range between two colors in R] using colorRampPalette()
* [http://novyden.blogspot.com/2013/09/how-to-expand-color-palette-with-ggplot.html How to expand color palette with ggplot and RColorBrewer]
* palette_explorer() function from the [https://cran.r-project.org/web/packages/tmaptools/index.html tmaptools] package. See [https://www.computerworld.com/article/3184778/data-analytics/6-useful-r-functions-you-might-not-know.html selecting color palettes with shiny].
* [http://www.cookbook-r.com/ Cookbook for R]
* [http://ggplot2.tidyverse.org/reference/scale_brewer.html Sequential, diverging and qualitative colour scales/palettes from colorbrewer.org]: scale_colour_brewer(), scale_fill_brewer(), ...
* http://colorbrewer2.org/
* It seems there is no choice of getting only 2 colors no matter which set name we can use
* To see the set names used in brewer.pal, see
** [https://www.rdocumentation.org/packages/RColorBrewer/versions/1.1-2/topics/RColorBrewer RColorBrewer::display.brewer.all()]
** [https://rpubs.com/flowertear/224344 Output]
** Especially, '''[http://colorbrewer2.org/#type=qualitative&scheme=Set1&n=4 Set1]''' from http://colorbrewer2.org/
* To list all R color names, colors().
** [http://research.stowers.org/mcm/efg/R/Color/Chart/ColorChart.pdf Color Chart] (include Hex and RGB) & [http://research.stowers.org/mcm/efg/Report/UsingColorInR.pdf Using Color in R] from http://research.stowers.org
** Code to generate rectangles with colored background https://www.r-graph-gallery.com/42-colors-names/
* http://www.bauer.uh.edu/parks/truecolor.htm Interactive RGB, Alpha and Color Picker
* http://deanattali.com/blog/colourpicker-package/ Not sure what it is doing
* [http://www.lifehack.org/484519/how-to-choose-the-best-colors-for-your-data-charts How to Choose the Best Colors For Your Data Charts]
* [http://novyden.blogspot.com/2013/09/how-to-expand-color-palette-with-ggplot.html How to expand color palette with ggplot and RColorBrewer]
* [http://sape.inf.usi.ch/quick-reference/ggplot2/colour Color names in R]
<ul>
<li>[https://stackoverflow.com/questions/28461326/convert-hex-color-code-to-color-name convert hex value to color names]
{{Pre}}
library(plotrix)
sapply(rainbow(4), color.id) # color.id is a function
          # it is used to identify closest match to a color
sapply(palette(), color.id)
sapply(RColorBrewer::brewer.pal(4, "Set1"), color.id)
</pre>
</li></ul>
* [https://www.rdocumentation.org/packages/grDevices/versions/3.5.3/topics/hsv hsv()] function. [https://eranraviv.com/matrix-style-screensaver-in-r/ Matrix-style screensaver in R]


Advantage
Below is an example using the option ''scale_fill_brewer''(palette = "[http://colorbrewer2.org/#type=qualitative&scheme=Paired&n=9 Paired]"). See the source code at [https://gist.github.com/JohannesFriedrich/c7d80b4e47b3331681cab8e9e7a46e17 gist]. Note that only '''set1''' and '''set3''' palettes in '''qualitative scheme''' can support up to 12 classes.  
* the web applications are created on desktop, whether it is Windows, Mac or Linux.  
* No Apache is needed.
* create [http://jeffreyhorner.tumblr.com/post/4723187316/introducing-rook multiple applications] at the same time. This complements the limit of rApache.  


----
According to the information from the colorbrew website, '''qualitative''' schemes do not imply magnitude differences between legend classes, and hues are used to create the primary visual differences between classes.


4 lines of code [http://jeffreybreen.wordpress.com/2011/04/25/4-lines-of-r-to-get-you-started-using-the-rook-web-server-interface/ example].
[[:File:GgplotPalette.svg]]


<pre>
=== [http://rpubs.com/gaston/colortools colortools] ===
library(Rook)
Tools that allow users generate color schemes and palettes
s <- Rhttpd$new()
s$start(quiet=TRUE)
s$print()
s$browse(1)  # OR s$browse("RookTest")
</pre>
Notice that after s$browse() command, the cursor will return to R because the command just a shortcut to open the web page http://127.0.0.1:10215/custom/RookTest.


[[File:Rook.png|100px]]
=== [https://github.com/daattali/colourpicker colourpicker] ===
[[File:Rook2.png|100px]]
A Colour Picker Tool for Shiny and for Selecting Colours in Plots
[[File:Rookapprnorm.png|100px]]


We can add Rook '''application''' to the server; see ?Rhttpd.
=== eyedroppeR ===
<pre>
[http://gradientdescending.com/select-colours-from-an-image-in-r-with-eyedropper/ Select colours from an image in R with {eyedroppeR}]
s$add(
    app=system.file('exampleApps/helloworld.R',package='Rook'),name='hello'
)
s$add(
    app=system.file('exampleApps/helloworldref.R',package='Rook'),name='helloref'
)
s$add(
    app=system.file('exampleApps/summary.R',package='Rook'),name='summary'
)


s$print()
== [https://github.com/kevinushey/rex rex] ==
Friendly Regular Expressions


#Server started on 127.0.0.1:10221
== [http://cran.r-project.org/web/packages/formatR/index.html formatR] ==
#[1] RookTest http://127.0.0.1:10221/custom/RookTest
'''The best strategy to avoid failure is to put comments in complete lines or after complete R expressions.'''
#[2] helloref http://127.0.0.1:10221/custom/helloref
#[3] summary  http://127.0.0.1:10221/custom/summary
#[4] hello    http://127.0.0.1:10221/custom/hello


#  Stops the server but doesn't uninstall the app
See also [http://stackoverflow.com/questions/3017877/tool-to-auto-format-r-code this discussion] on stackoverflow talks about R code reformatting.
## Not run:  
s$stop()


## End(Not run)
<pre>
s$remove(all=TRUE)
library(formatR)
rm(s)
tidy_source("Input.R", file = "output.R", width.cutoff=70)
tidy_source("clipboard")  
# default width is getOption("width") which is 127 in my case.
</pre>
</pre>
For example, the interface and the source code of ''summary'' app are given below


[[File:Rookappsummary.png|100px]]
Some issues
 
* Comments appearing at the beginning of a line within a long complete statement. This will break tidy_source().
<nowiki>
<pre>
app <- function(env) {
cat("abcd",
    req <- Rook::Request$new(env)
    # This is my comment
    res <- Rook::Response$new()
    "defg")
    res$write('Choose a CSV file:\n')
</pre>
    res$write('<form method="POST" enctype="multipart/form-data">\n')
will result in
    res$write('<input type="file" name="data">\n')
<pre>
     res$write('<input type="submit" name="Upload">\n</form>\n<br>')
> tidy_source("clipboard")
 
Error in base::parse(text = code, srcfile = NULL) :
    if (!is.null(req$POST())){
  3:1: unexpected string constant
data <- req$POST()[['data']]
2: invisible(".BeGiN_TiDy_IdEnTiFiEr_HaHaHa# This is my comment.HaHaHa_EnD_TiDy_IdEnTiFiEr")
res$write("<h3>Summary of Data</h3>");
3: "defg"
res$write("<pre>")
  ^
res$write(paste(capture.output(summary(read.csv(data$tempfile,stringsAsFactors=FALSE)),file=NULL),collapse='\n'))
</pre>
res$write("</pre>")
* Comments appearing at the end of a line within a long complete statement ''won't break'' tidy_source() but tidy_source() cannot re-locate/tidy the comma sign.
res$write("<h3>First few lines (head())</h3>");
<pre>
res$write("<pre>")
cat("abcd"
res$write(paste(capture.output(head(read.csv(data$tempfile,stringsAsFactors=FALSE)),file=NULL),collapse='\n'))
     ,"defg"   # This is my comment
res$write("</pre>")
  ,"ghij")
    }
</pre>
    res$finish()
will become
}
<pre>
</nowiki>
cat("abcd", "defg"  # This is my comment
 
, "ghij")  
More example:
</pre>
* http://lamages.blogspot.com/2012/08/rook-rocks-example-with-googlevis.html
Still bad!!
* [http://www.road2stat.com/cn/r/rook.html Self-organizing map]
* Comments appearing at the end of a line within a long complete statement ''breaks'' tidy_source() function. For example,
* Deploy Rook apps with rApache. [http://jeffreyhorner.tumblr.com/post/27861973339/deploy-rook-apps-with-rapache-part-i First one] and [http://jeffreyhorner.tumblr.com/post/33814488298/deploy-rook-apps-part-ii two].
<pre>
* [https://rud.is/b/2016/07/05/a-simple-prediction-web-service-using-the-new-firery-package/ A Simple Prediction Web Service Using the New fiery Package]
cat("</p>",
 
"<HR SIZE=5 WIDTH=\"100%\" NOSHADE>",
=== [https://code.google.com/p/sumo/ sumo] ===
ifelse(codeSurv == 0,"<h3><a name='Genes'><b><u>Genes which are differentially expressed among classes:</u></b></a></h3>", #4/9/09
Sumo is a fully-functional web application template that exposes an authenticated user's R session within java server pages. See the paper http://journal.r-project.org/archive/2012-1/RJournal_2012-1_Bergsma+Smith.pdf.
                    "<h3><a name='Genes'><b><u>Genes significantly associated with survival:</u></b></a></h3>"),
 
file=ExternalFileName, sep="\n", append=T)
=== [http://www.stat.ucla.edu/~jeroen/stockplot Stockplot] ===
</pre>
 
will result in
=== [http://www.rforge.net/FastRWeb/ FastRWeb] ===
<pre>
http://cran.r-project.org/web/packages/FastRWeb/index.html
> tidy_source("clipboard", width.cutoff=70)
 
Error in base::parse(text = code, srcfile = NULL) :  
=== [http://sysbio.mrc-bsu.cam.ac.uk/Rwui/tutorial/Instructions.html Rwui] ===
  3:129: unexpected SPECIAL
 
2: "<HR SIZE=5 WIDTH=\"100%\" NOSHADE>" ,
=== [http://cran.r-project.org/web/packages/CGIwithR/index.html CGHWithR] and [http://cran.r-project.org/web/packages/WebDevelopR/ WebDevelopR] ===
3: ifelse ( codeSurv == 0 , "<h3><a name='Genes'><b><u>Genes which are differentially expressed among classes:</u></b></a></h3>" , %InLiNe_IdEnTiFiEr%
CGHwithR is still working with old version of R although it is removed from CRAN. Its successor is WebDevelopR. Its The vignette (year 2013) provides a review of several available methods.
</pre>
 
* ''width.cutoff'' parameter is not always working. For example, there is no any change for the following snippet though I hope it will move the cat() to the next line.
=== [http://www.rstudio.com/ide/docs/advanced/manipulate manipulate] from RStudio ===
<pre>
This is not a web application. But the '''manipulate''' package can be used to create interactive plot within R(Studio) environment easily. Its source is available at [https://github.com/rstudio/rstudio/tree/master/src/cpp/r/R/packages/manipulate here].
if (codePF & !GlobalTest & !DoExactPermTest) cat(paste("Multivariate Permutations test was computed based on",  
 
    NumPermutations, "random permutations"), "<BR>", " ", file = ExternalFileName,  
Mathematica also has manipulate function for plotting; see [http://reference.wolfram.com/mathematica/tutorial/IntroductionToManipulate.html here].
    sep = "\n", append = T)
 
</pre>
=== [https://github.com/att/rcloud RCloud] ===
* It merges lines though I don't always want to do that. For example
RCloud is an environment for collaboratively creating and sharing data analysis scripts. RCloud lets you mix analysis code in R, HTML5, Markdown, Python, and others. Much like Sage, iPython notebooks and Mathematica, RCloud provides a notebook interface that lets you easily record a session and annotate it with text, equations, and supporting images.
<pre>
 
cat("abcd"
See also the [http://user2014.stat.ucla.edu/abstracts/talks/193_Harner.pdf Talk] in UseR 2014.
    ,"defg"
 
  ,"ghij")
=== Dropbox access ===
</pre>
[https://cran.r-project.org/web/packages/rdrop2/index.html rdrop2] package
will become
 
<pre>
=== Web page scraping ===
cat("abcd", "defg", "ghij")  
[http://blog.rstudio.org/2014/11/24/rvest-easy-web-scraping-with-r/ rvest] package.
</pre>
 
[http://datascienceplus.com/visualizing-obesity-across-united-states-by-using-data-from-wikipedia/ Visualizing obesity across United States by using data from Wikipedia]
 
=== Send email ===
* [https://github.com/rpremraj/mailR/ mailR] package
 
=== [http://www.ncbi.nlm.nih.gov/geo/ GEO (Gene Expression Omnibus)] ===
See [[GEO#R_packages|this internal link]].
 
=== Interactive html output ===
==== [http://cran.r-project.org/web/packages/sendplot/index.html sendplot] ====
==== [http://cran.r-project.org/web/packages/RIGHT/index.html RIGHT] ====
The supported plot types include scatterplot, barplot, box plot, line plot and pie plot.
 
In addition to tooltip boxes, the package can create a [http://righthelp.github.io/tutorial/interactivity table showing all information about selected nodes].
 
==== [http://cran.r-project.org/web/packages/d3Network/index.html d3Network] ====
* http://christophergandrud.github.io/d3Network/
<source lang="rsplus">
library(d3Network)
 
Source <- c("A", "A", "A", "A", "B", "B", "C", "C", "D")  
Target <- c("B", "C", "D", "J", "E", "F", "G", "H", "I")  
NetworkData <- data.frame(Source, Target)
 
d3SimpleNetwork(NetworkData, height = 800, width = 1024, file="tmp.html")
</source>
 
==== [http://cran.r-project.org/web/packages/htmlwidgets/ htmlwidgets for R] ====
Embed widgets in R Markdown documents and Shiny web applications. Its official website is at http://www.htmlwidgets.org/.
 
==== [http://cran.r-project.org/web/packages/networkD3/index.html networkD3] ====
This is a port of Christopher Gandrud's [http://christophergandrud.github.io/d3Network/ d3Network] package to the htmlwidgets framework.
 
==== [http://cran.r-project.org/web/packages/scatterD3/index.html scatterD3] ====
scatterD3 is an HTML R widget for interactive scatter plots visualization. It is based on the htmlwidgets R package and on the d3.js javascript library.


==== [http://blog.rstudio.org/2015/06/24/d3heatmap/ d3heatmap] ====
== styler ==
A package generats interactive heatmaps using d3.js and htmlwidgets. The following screenshots shows 3 features.
https://cran.r-project.org/web/packages/styler/index.html Pretty-prints R code without changing the user's formatting intent.
* Shows the row/column/value under the mouse cursor
* Zoom in a region (click on the zoom-in image will bring back the original heatmap)
* Highlight a row or a column (click the label of another row will highlight another row. Click the same label again will bring back the original image)


[[File:D3heatmap mouseover.png|200px]] [[File:D3heatmap zoomin.png|200px]] [[File:D3heatmap highlight.png|200px]]
== Download papers ==
=== [http://cran.r-project.org/web/packages/biorxivr/index.html biorxivr] ===
Search and Download Papers from the bioRxiv Preprint Server (biology)


==== [https://cran.r-project.org/web/packages/svgPanZoom/index.html svgPanZoom] ====
=== [http://cran.r-project.org/web/packages/aRxiv/index.html aRxiv] ===
This 'htmlwidget' provides pan and zoom interactivity to R graphics, including 'base', 'lattice', and 'ggplot2'. The interactivity is provided through the 'svg-pan-zoom.js' library.
Interface to the arXiv API


==== DT: An R interface to the DataTables library ====
=== [https://cran.r-project.org/web/packages/pdftools/index.html pdftools] ===
* http://blog.rstudio.org/2015/06/24/dt-an-r-interface-to-the-datatables-library/
* http://ropensci.org/blog/2016/03/01/pdftools-and-jeroen
* http://r-posts.com/how-to-extract-data-from-a-pdf-file-with-r/
* https://ropensci.org/technotes/2018/12/14/pdftools-20/


==== plotly ====
== [https://github.com/ColinFay/aside aside]: set it aside ==
* [http://moderndata.plot.ly/power-curves-r-plotly-ggplot2/ Power curves] and ggplot2.
An RStudio addin to run long R commands aside your current session.
* [http://moderndata.plot.ly/time-series-charts-by-the-economist-in-r-using-plotly/ TIME SERIES CHARTS BY THE ECONOMIST IN R USING PLOTLY]


== Creating local repository for CRAN and Bioconductor (focus on Windows binary packages only) ==
== Teaching ==
=== How to set up a local repository ===
* [https://cran.r-project.org/web/packages/smovie/vignettes/smovie-vignette.html smovie]: Some Movies to Illustrate Concepts in Statistics


* CRAN specific: http://cran.r-project.org/mirror-howto.html
== Organize R research project ==
* Bioconductor specific: http://www.bioconductor.org/about/mirrors/mirror-how-to/
* [https://cran.r-project.org/web/views/ReproducibleResearch.html CRAN Task View: Reproducible Research]
* [https://ntguardian.wordpress.com/2019/02/04/organizing-r-research-projects-cpat-case-study/ Organizing R Research Projects: CPAT, A Case Study]
* [https://www.tidyverse.org/articles/2017/12/workflow-vs-script/ Project-oriented workflow]. It suggests the [https://github.com/r-lib/here here] package. Don't use '''setwd()''' and '''rm(list = ls())'''.
** [https://rstats.wtf/safe-paths.html Practice safe paths]. Use projects and the [https://cran.r-project.org/web/packages/here/index.html here] package.
** In RStudio, if we try to send a few lines of code and one of the line contains '''setwd()''', it will give a message: ''The working directory was changed to XXX inside a notebook chunk. The working directory will be reset when the chunk is finished running. Use the knitr root.dir option in the setup chunk to change the working directory for notebook chunks.''
** [http://jenrichmond.rbind.io/post/how-to-use-the-here-package/ how to use the `here` package]
** No update for the ''here'' package after 2020-12. Consider [https://github.com/r-lib/usethis usethis] package (Automate project and package setup).
* drake project
** [https://ropensci.org/blog/2018/02/06/drake/ The prequel to the drake R package]
** [https://ropenscilabs.github.io/drake-manual/index.html The drake R Package User Manual]
* [https://docs.ropensci.org/targets/ targets] package
* [http://projecttemplate.net/ ProjectTemplate]


General guide: http://cran.r-project.org/doc/manuals/R-admin.html#Setting-up-a-package-repository
=== How to save (and load) datasets in R (.RData vs .Rds file) ===
[https://rcrastinate.rbind.io/post/how-to-save-and-load-data-in-r-an-overview/ How to save (and load) datasets in R: An overview]


Utilities such as install.packages can be pointed at any CRAN-style repository, and R users may want to set up their own. The ‘base’ of a repository is a URL such as http://www.omegahat.org/R/: this must be an URL scheme that download.packages supports (which also includes ‘ftp://’ and ‘file://’, but not on most systems ‘https://’). '''Under that base URL there should be directory trees for one or more of the following types of package distributions:'''  
=== Naming convention ===
<ul>
<li>[https://stackoverflow.com/a/1946879 What is your preferred style for naming variables in R?]
* Use of period separator: they can get mixed up in simple method dispatch. However, it is used by base R ([https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/make.names make.names()], read.table(), et al)
* Use of underscores: really annoying for ESS users
* '''camelCase''': Winner
<li>However, the [https://stackoverflow.com/a/13413278 survey] said (no surprises perhaps) that  
* '''lowerCamelCase''' was most often used for function names,
* '''period.separated''' names most often used for parameters.
<li>[https://datamanagement.hms.harvard.edu/collect/file-naming-conventions What are file naming conventions?]
<li>[https://www.r-bloggers.com/2014/07/consistent-naming-conventions-in-r/ Consistent naming conventions in R]
<li>http://adv-r.had.co.nz/Style.html
<li>[https://www.r-bloggers.com/2011/07/testing-for-valid-variable-names/ Testing for valid variable names]
<li>R reserved words ?Reserved
* [https://www.datamentor.io/r-programming/reserved-words/ R Reserved Words]
* Among these words, if, else, repeat, while, function, for, '''in''', next and break are used for conditions, loops and user defined functions.
<li>Microarray/RNA-seq data
<pre>
clinicalDesignData  # clnDesignData
geneExpressionData  # gExpData
geneAnnotationData  # gAnnoData


* "source": located at src/contrib and containing .tar.gz files. Other forms of compression can be used, e.g. .tar.bz2 or .tar.xz files.
dataClinicalDesign
* '''"win.binary": located at bin/windows/contrib/x.y for R versions x.y.z and containing .zip files for Windows.'''
dataGeneExpression
* "mac.binary.leopard": located at bin/macosx/leopard/contrib/x.y for R versions x.y.z and containing .tgz files.
dataAnnotation
</pre>
<pre>
# Search all variables ending with .Data
ls()[grep("\\.Data$", ls())]
# Search all variables starting with data_
ls()[grep("^data_", ls())]
</pre>
</ul>


Each terminal directory must also contain a PACKAGES file. This can be a concatenation of the DESCRIPTION files of the packages separated by blank lines, but only a few of the fields are needed. The simplest way to set up such a file is to use function write_PACKAGES in the tools package, and its help explains which fields are needed. Optionally there can also be a PACKAGES.gz file, a gzip-compressed version of PACKAGES—as this will be downloaded in preference to PACKAGES it should be included for large repositories. (If you have a mis-configured server that does not report correctly non-existent files you will need PACKAGES.gz.)
=== Efficient Data Management in R ===
[https://www.mzes.uni-mannheim.de/socialsciencedatalab/article/efficient-data-r/ Efficient Data Management in R]. .Rprofile, renv package and dplyr package.


To add your repository to the list offered by setRepositories(), see the help file for that function.
== Text to speech ==
[https://shirinsplayground.netlify.com/2018/06/googlelanguager/ Text-to-Speech with the googleLanguageR package]


A repository can contain subdirectories, when the descriptions in the PACKAGES file of packages in subdirectories must include a line of the form
== Speech to text ==
https://github.com/ggerganov/whisper.cpp and an R package [https://github.com/bnosac/audio.whisper audio.whisper]


<nowiki>Path: path/to/subdirectory</nowiki>
== Weather data ==
* [https://github.com/ropensci/prism prism] package
* [http://www.weatherbase.com/weather/weather.php3?s=507781&cityname=Rockville-Maryland-United-States-of-America Weatherbase]


—once again write_PACKAGES is the simplest way to set this up.
== logR ==
https://github.com/jangorecki/logR


==== Space requirement if we want to mirror WHOLE repository ====
== Progress bar ==
* Whole CRAN takes about 92GB (rsync -avn  cran.r-project.org::CRAN > ~/Downloads/cran).
https://github.com/r-lib/progress#readme
* Bioconductor is big (> 64G for BioC 2.11). Please check the size of what will be transferred with e.g. (rsync -avn bioconductor.org::2.11 > ~/Downloads/bioc) and make sure you have enough room on your local disk before you start.


On the other hand, we if only care about Windows binary part, the space requirement is largely reduced.
Configurable Progress bars, they may include percentage, elapsed time, and/or the estimated completion time. They work in terminals, in 'Emacs' 'ESS', 'RStudio', 'Windows' 'Rgui' and the 'macOS'.
* CRAN: 2.7GB
* Bioconductor: 28GB.


==== Misc notes ====
== cron ==
* If the binary package was built on R 2.15.1, then it cannot be installed on R 2.15.2. But vice is OK.
* [https://github.com/bnosac/cronr cronR]
* Remember to issue "--delete" option in rsync, otherwise old version of package will be installed.
* [https://mathewanalytics.com/building-a-simple-pipeline-in-r/ Building a Simple Pipeline in R]
* The repository still need src directory. If it is missing, we will get an error
 
<pre>
== beepr: Play A Short Sound ==
Warning: unable to access index for repository http://arraytools.no-ip.org/CRAN/src/contrib
https://www.rdocumentation.org/packages/beepr/versions/1.3/topics/beep. Try sound=3 "fanfare", 4 "complete", 5 "treasure", 7 "shotgun", 8 "mario".
Warning message:
 
package ‘glmnet’ is not available (for R version 2.15.2)
== utils package ==
</pre>
https://www.rdocumentation.org/packages/utils/versions/3.6.2
The error was given by available.packages() function.


To bypass the requirement of src directory, I can use
== tools package ==
<pre>
* https://www.rdocumentation.org/packages/tools/versions/3.6.2
install.packages("glmnet", contriburl = contrib.url(getOption('repos'), "win.binary"))
* [https://www.r-bloggers.com/2023/08/three-four-r-functions-i-enjoyed-this-week/ Where in the file are there non ASCII characters?], [https://rdocumentation.org/packages/tools/versions/3.6.2/topics/showNonASCII tools::showNonASCIIfile(<filename>)]
</pre>
but there may be a problem when we use biocLite() command.


I find a workaround. Since the error comes from missing CRAN/src directory, we just need to make sure the directory CRAN/src/contrib exists AND either CRAN/src/contrib/PACKAGES or CRAN/src/contrib/PACKAGES.gz exists.
= Different ways of using R =
[https://www.amazon.com/Extending-Chapman-Hall-John-Chambers/dp/1498775713 Extending R] by John M. Chambers (2016)


==== To create CRAN repository ====
== 10 things R can do that might surprise you ==
Before creating a local repository please give a dry run first. You don't want to be surprised how long will it take to mirror a directory.
https://simplystatistics.org/2019/03/13/10-things-r-can-do-that-might-surprise-you/


Dry run (-n option). Pipe out the process to a text file for an examination.
== R call C/C++ ==
<pre>
Mainly talks about .C() and .Call().
rsync -avn cran.r-project.org::CRAN > crandryrun.txt
</pre>
To mirror only partial repository, it is necessary to create directories before running rsync command.
<pre>
cd
mkdir -p ~/Rmirror/CRAN/bin/windows/contrib/2.15
rsync -rtlzv --delete cran.r-project.org::CRAN/bin/windows/contrib/2.15/ ~/Rmirror/CRAN/bin/windows/contrib/2.15
(one line with space before ~/Rmirror)


# src directory is very large (~27GB) since it contains source code for each R version.
Note that scalars and arrays must be passed using pointers. So if we want to access a function not exported from a package, we may need to modify the function to make the arguments as pointers.
# We just need the files PACKAGES and PACKAGES.gz in CRAN/src/contrib. So I comment out the following line.
# rsync -rtlzv --delete cran.r-project.org::CRAN/src/ ~/Rmirror/CRAN/src/
mkdir -p ~/Rmirror/CRAN/src/contrib
rsync -rtlzv --delete cran.r-project.org::CRAN/src/contrib/PACKAGES ~/Rmirror/CRAN/src/contrib/
rsync -rtlzv --delete cran.r-project.org::CRAN/src/contrib/PACKAGES.gz ~/Rmirror/CRAN/src/contrib/
</pre>
And optionally
<pre>
library(tools)
write_PACKAGES("~/Rmirror/CRAN/bin/windows/contrib/2.15", type="win.binary")
</pre>
and if we want to get src directory
<pre>
rsync -rtlzv --delete cran.r-project.org::CRAN/src/contrib/*.tar.gz ~/Rmirror/CRAN/src/contrib/
rsync -rtlzv --delete cran.r-project.org::CRAN/src/contrib/2.15.3 ~/Rmirror/CRAN/src/contrib/
</pre>


We can use '''du -h''' to check the folder size.  
* [http://cran.r-project.org/doc/manuals/R-exts.html R-Extension manual] of course.
* [http://r-pkgs.had.co.nz/src.html Compiled Code] chapter from 'R Packages' by Hadley Wickham
* http://faculty.washington.edu/kenrice/sisg-adv/sisg-07.pdf
* http://www.stat.berkeley.edu/scf/paciorek-cppWorkshop.pdf (Very useful)
* http://www.stat.harvard.edu/ccr2005/
* http://mazamascience.com/WorkingWithData/?p=1099
* [https://youtube.com/playlist?list=PLwc48KSH3D1OkObQ22NHbFwEzof2CguJJ Make an R package with C++ code] (a playlist from youtube)
* [https://working-with-data.mazamascience.com/2021/07/16/using-r-calling-c-code-hello-world/ Using R – Calling C code ‘Hello World!’]
* [http://www.haowulab.org//pages/computing.html Computing tip] by Hao Wu


For example (as of 1/7/2013),
=== .Call ===
<pre>
* [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/CallExternal ?.Call]
$ du -k ~/Rmirror --max-depth=1 --exclude ".*" | sort -nr | cut -f2 | xargs -d '\n' du -sh
* [http://mazamascience.com/WorkingWithData/?p=1099 Using R — .Call(“hello”)]
30G /home/brb/Rmirror
* http://adv-r.had.co.nz/C-interface.html
28G /home/brb/Rmirror/Bioc
* [https://working-with-data.mazamascience.com/2021/07/16/using-r-callhello/ Using R – .Call(“hello”)]
2.7G /home/brb/Rmirror/CRAN
</pre>


==== To create Bioconductor repository ====
Be sure to add the ''PACKAGE'' parameter to avoid an error like
Dry run
<pre>
<pre>
rsync -avn bioconductor.org::2.11 > biocdryrun.txt
cvfit <- cv.grpsurvOverlap(X, Surv(time, event), group,
                            cv.ind = cv.ind, seed=1, penalty = 'cMCP')
Error in .Call("standardize", X) :
  "standardize" not resolved from current namespace (grpreg)
</pre>
</pre>
Then creates directories before running rsync.


<pre>
=== NAMESPACE file & useDynLib ===
cd
* https://cran.r-project.org/doc/manuals/r-release/R-exts.html#useDynLib
mkdir -p ~/Rmirror/Bioc
* We don't need to include double quotes around the C/Fortran subroutines in .C() or .Fortran()
wget -N http://www.bioconductor.org/biocLite.R -P ~/Rmirror/Bioc
* digest package example: [https://github.com/cran/digest/blob/master/NAMESPACE NAMESPACE] and [https://github.com/cran/digest/blob/master/R/digest.R R functions] using .Call().
</pre>
* stats example: [https://github.com/wch/r-source/blob/trunk/src/library/stats/NAMESPACE NAMESPACE]
where '''-N''' is to overwrite original file if the size or timestamp change and '''-P''' in wget means an output directory, not a file name.


Optionally, we can add the following in order to see the Bioconductor front page.
(From [https://cran.r-project.org/doc/manuals/r-release/R-exts.html#dyn_002eload-and-dyn_002eunload Writing R Extensions manual]) Loading is most often done automatically based on the '''useDynLib()''' declaration in the '''NAMESPACE''' file, but may be done explicitly via a call to '''library.dynam()'''. This has the form
<pre>
{{Pre}}
rsync -zrtlv  --delete bioconductor.org::2.11/BiocViews.html ~/Rmirror/Bioc/packages/2.11/
library.dynam("libname", package, lib.loc)
rsync -zrtlv  --delete bioconductor.org::2.11/index.html ~/Rmirror/Bioc/packages/2.11/
</pre>
</pre>


The software part (aka bioc directory) installation:
=== library.dynam.unload() ===
<pre>
* https://stat.ethz.ch/R-manual/R-devel/library/base/html/library.dynam.html
cd
* http://r-pkgs.had.co.nz/src.html. The '''library.dynam.unload()''' function should be placed in '''.onUnload()''' function. This function can be saved in any R files.
mkdir -p ~/Rmirror/Bioc/packages/2.11/bioc/bin/windows
* digest package example [https://github.com/cran/digest/blob/master/R/zzz.R zzz.R]
mkdir -p ~/Rmirror/Bioc/packages/2.11/bioc/src
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/bin/windows/ ~/Rmirror/Bioc/packages/2.11/bioc/bin/windows
# Either rsync whole src directory or just essential files
# rsync -zrtlv  --delete bioconductor.org::2.11/bioc/src/ ~/Rmirror/Bioc/packages/2.11/bioc/src
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/src/contrib/PACKAGES ~/Rmirror/Bioc/packages/2.11/bioc/src/contrib/
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/src/contrib/PACKAGES.gz ~/Rmirror/Bioc/packages/2.11/bioc/src/contrib/
# Optionally the html part
mkdir -p ~/Rmirror/Bioc/packages/2.11/bioc/html
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/html/ ~/Rmirror/Bioc/packages/2.11/bioc/html
mkdir -p ~/Rmirror/Bioc/packages/2.11/bioc/vignettes
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/vignettes/ ~/Rmirror/Bioc/packages/2.11/bioc/vignettes
mkdir -p ~/Rmirror/Bioc/packages/2.11/bioc/news
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/news/ ~/Rmirror/Bioc/packages/2.11/bioc/news
mkdir -p ~/Rmirror/Bioc/packages/2.11/bioc/licenses
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/licenses/ ~/Rmirror/Bioc/packages/2.11/bioc/licenses
mkdir -p ~/Rmirror/Bioc/packages/2.11/bioc/manuals
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/manuals/ ~/Rmirror/Bioc/packages/2.11/bioc/manuals
mkdir -p ~/Rmirror/Bioc/packages/2.11/bioc/readmes
rsync -zrtlv  --delete bioconductor.org::2.11/bioc/readmes/ ~/Rmirror/Bioc/packages/2.11/bioc/readmes
</pre>
and annotation (aka data directory) part:
<pre>
mkdir -p ~/Rmirror/Bioc/packages/2.11/data/annotation/bin/windows
mkdir -p ~/Rmirror/Bioc/packages/2.11/data/annotation/src/contrib
# one line for each of the following
rsync -zrtlv --delete bioconductor.org::2.11/data/annotation/bin/windows/ ~/Rmirror/Bioc/packages/2.11/data/annotation/bin/windows
rsync -zrtlv --delete bioconductor.org::2.11/data/annotation/src/contrib/PACKAGES ~/Rmirror/Bioc/packages/2.11/data/annotation/src/contrib/
rsync -zrtlv --delete bioconductor.org::2.11/data/annotation/src/contrib/PACKAGES.gz ~/Rmirror/Bioc/packages/2.11/data/annotation/src/contrib/
</pre>
and experiment directory:
<pre>
mkdir -p ~/Rmirror/Bioc/packages/2.11/data/experiment/bin/windows/contrib/2.15
mkdir -p ~/Rmirror/Bioc/packages/2.11/data/experiment/src/contrib
# one line for each of the following
# Note that we are cheating by only downloading PACKAGES and PACKAGES.gz files
rsync -zrtlv --delete bioconductor.org::2.11/data/experiment/bin/windows/contrib/2.15/PACKAGES ~/Rmirror/Bioc/packages/2.11/data/experiment/bin/windows/contrib/2.15/
rsync -zrtlv --delete bioconductor.org::2.11/data/experiment/bin/windows/contrib/2.15/PACKAGES.gz ~/Rmirror/Bioc/packages/2.11/data/experiment/bin/windows/contrib/2.15/
rsync -zrtlv --delete bioconductor.org::2.11/data/experiment/src/contrib/PACKAGES ~/Rmirror/Bioc/packages/2.11/data/experiment/src/contrib/
rsync -zrtlv --delete bioconductor.org::2.11/data/experiment/src/contrib/PACKAGES.gz ~/Rmirror/Bioc/packages/2.11/data/experiment/src/contrib/
</pre>
and extra directory:
<pre>
mkdir -p ~/Rmirror/Bioc/packages/2.11/extra/bin/windows/contrib/2.15
mkdir -p ~/Rmirror/Bioc/packages/2.11/extra/src/contrib
# one line for each of the following
# Note that we are cheating by only downloading PACKAGES and PACKAGES.gz files
rsync -zrtlv --delete bioconductor.org::2.11/extra/bin/windows/contrib/2.15/PACKAGES ~/Rmirror/Bioc/packages/2.11/extra/bin/windows/contrib/2.15/
rsync -zrtlv --delete bioconductor.org::2.11/extra/bin/windows/contrib/2.15/PACKAGES.gz ~/Rmirror/Bioc/packages/2.11/extra/bin/windows/contrib/2.15/
rsync -zrtlv --delete bioconductor.org::2.11/extra/src/contrib/PACKAGES ~/Rmirror/Bioc/packages/2.11/extra/src/contrib/
rsync -zrtlv --delete bioconductor.org::2.11/extra/src/contrib/PACKAGES.gz ~/Rmirror/Bioc/packages/2.11/extra/src/contrib/
</pre>


=== To test local repository ===
=== gcc ===
[http://rorynolan.rbind.io/2019/06/30/strexgcc/ Coping with varying `gcc` versions and capabilities in R packages]


==== Create soft links in Apache server ====
=== Primitive functions ===
<pre>
[https://nathaneastwood.github.io/2020/02/01/primitive-functions-list/ Primitive Functions List]
su
ln -s /home/brb/Rmirror/CRAN /var/www/html/CRAN
ln -s /home/brb/Rmirror/Bioc /var/www/html/Bioc
ls -l /var/www/html
</pre>
The soft link mode should be 777.


==== To test CRAN ====
== SEXP ==
Replace the host name arraytools.no-ip.org by IP address 10.133.2.111 if necessary.
Some examples from packages


<pre>
* [https://www.bioconductor.org/packages/release/bioc/html/sva.html sva] package has one C code function
r <- getOption("repos"); r["CRAN"] <- "http://arraytools.no-ip.org/CRAN"
options(repos=r)
install.packages("glmnet")
</pre>
We can test if the backup server is working or not by installing a package which was removed from the CRAN. For example, 'ForImp' was removed from CRAN in 11/8/2012, but I still a local copy built on R 2.15.2 (run rsync on 11/6/2012).


<pre>
== R call Fortran ==
r <- getOption("repos"); r["CRAN"] <- "http://cran.r-project.org"
* [https://stat.ethz.ch/pipermail/r-devel/2015-March/070851.html R call Fortran 90]
r <- c(r, BRB='http://arraytools.no-ip.org/CRAN')
* [https://www.r-bloggers.com/the-need-for-speed-part-1-building-an-r-package-with-fortran-or-c/ The Need for Speed Part 1: Building an R Package with Fortran (or C)] (Very detailed)
#                        CRAN                            CRANextra                                  BRB
# "http://cran.r-project.org" "http://www.stats.ox.ac.uk/pub/RWin"  "http://arraytools.no-ip.org/CRAN"
options(repos=r)
install.packages('ForImp')
</pre>


Note by default, CRAN mirror is selected interactively.
== Embedding R ==
<pre>
> getOption("repos")
                                CRAN                            CRANextra
                            "@CRAN@" "http://www.stats.ox.ac.uk/pub/RWin"
</pre>


==== To test Bioconductor ====
* See [http://cran.r-project.org/doc/manuals/R-exts.html#Linking-GUIs-and-other-front_002dends-to-R Writing for R Extensions] Manual Chapter 8.
<pre>
* [http://www.ci.tuwien.ac.at/Conferences/useR-2004/abstracts/supplements/Urbanek.pdf Talk by Simon Urbanek] in UseR 2004.
# CRAN part:
* [http://epub.ub.uni-muenchen.de/2085/1/tr012.pdf Technical report]  by Friedrich Leisch in 2007.
r <- getOption("repos"); r["CRAN"] <- "http://arraytools.no-ip.org/CRAN"
* https://stat.ethz.ch/pipermail/r-help/attachments/20110729/b7d86ed7/attachment.pl
options(repos=r)
# Bioconductor part:
options("BioC_mirror" = "http://arraytools.no-ip.org/Bioc")
source("http://bioconductor.org/biocLite.R")
# This source biocLite.R line can be placed either before or after the previous 2 lines
biocLite("aCGH")
</pre>


If there is a connection problem, check folder attributes.
=== An very simple example (do not return from shell) from Writing R Extensions manual ===
<pre>
The command-line R front-end, R_HOME/bin/exec/R, is one such example. Its source code is in file <src/main/Rmain.c>.
chmod -R 755 ~/CRAN/bin
</pre>


* Note that if a binary package was created for R 2.15.1, then it can be installed under R 2.15.1 but not R 2.15.2. The R console will show package xxx is not available (for R version 2.15.2).
This example can be run by
<pre>R_HOME/bin/R CMD R_HOME/bin/exec/R</pre>


* For binary installs, the function also checks for the availability of a source package on the same repository, and reports if the source package has a later version, or is available but no binary version is.
Note:
So for example, if the mirror does not have contents under src directory, we need to run the following line in order to successfully run ''install.packages()'' function.
# '''R_HOME/bin/exec/R''' is the R binary. However, it couldn't be launched directly unless R_HOME and LD_LIBRARY_PATH are set up. Again, this is explained in Writing R Extension manual.
<pre>
# '''R_HOME/bin/R''' is a shell-script front-end where users can invoke it. It sets up the environment for the executable. It can be copied to ''/usr/local/bin/R''. When we run ''R_HOME/bin/R'', it actually runs ''R_HOME/bin/R CMD R_HOME/bin/exec/R'' (see line 259 of ''R_HOME/bin/R'' as in R 3.0.2) so we know the important role of ''R_HOME/bin/exec/R''.
options(install.packages.check.source = "no")
</pre>


* If we only mirror the essential directories, we can run biocLite() successfully. However, the R console will give some warning
More examples of embedding can be found in ''tests/Embedding'' directory. Read <index.html> for more information about these test examples.
<pre>
> biocLite("aCGH")
BioC_mirror: http://arraytools.no-ip.org/Bioc
Using Bioconductor version 2.11 (BiocInstaller 1.8.3), R version 2.15.
Installing package(s) 'aCGH'
Warning: unable to access index for repository http://arraytools.no-ip.org/Bioc/packages/2.11/data/experiment/src/contrib
Warning: unable to access index for repository http://arraytools.no-ip.org/Bioc/packages/2.11/extra/src/contrib
Warning: unable to access index for repository http://arraytools.no-ip.org/Bioc/packages/2.11/data/experiment/bin/windows/contrib/2.15
Warning: unable to access index for repository http://arraytools.no-ip.org/Bioc/packages/2.11/extra/bin/windows/contrib/2.15
trying URL 'http://arraytools.no-ip.org/Bioc/packages/2.11/bioc/bin/windows/contrib/2.15/aCGH_1.36.0.zip'
Content type 'application/zip' length 2431158 bytes (2.3 Mb)
opened URL
downloaded 2.3 Mb


package ‘aCGH’ successfully unpacked and MD5 sums checked
=== An example from Bioconductor workshop ===
* What is covered in this section is different from [[R#Create_a_standalone_Rmath_library|Create and use a standalone Rmath library]].
* Use eval() function. See R-Ext [http://cran.r-project.org/doc/manuals/R-exts.html#Embedding-R-under-Unix_002dalikes 8.1] and [http://cran.r-project.org/doc/manuals/R-exts.html#Embedding-R-under-Windows 8.2] and [http://cran.r-project.org/doc/manuals/R-exts.html#Evaluating-R-expressions-from-C 5.11].
* http://stackoverflow.com/questions/2463437/r-from-c-simplest-possible-helloworld (obtained from searching R_tryEval on google)
* http://stackoverflow.com/questions/7457635/calling-r-function-from-c


The downloaded binary packages are in
Example:
        C:\Users\limingc\AppData\Local\Temp\Rtmp8IGGyG\downloaded_packages
Create [https://gist.github.com/arraytools/7d32d92fee88ffc029365d178bc09e75#file-embed-c embed.c] file.
Warning: unable to access index for repository http://arraytools.no-ip.org/Bioc/packages/2.11/data/experiment/bin/windows/contrib/2.15
Then build the executable. Note that I don't need to create R_HOME variable.
Warning: unable to access index for repository http://arraytools.no-ip.org/Bioc/packages/2.11/extra/bin/windows/contrib/2.15
> library()
</pre>
 
=== CRAN repository directory structure ===
The information below is specific to R 2.15.2. There are linux and macosx subdirecotries whenever there are windows subdirectory.
<pre>
<pre>
bin/winows/contrib/2.15
cd
src/contrib
tar xzvf
  /contrib/2.15.2
cd R-3.0.1
  /contrib/Archive
./configure --enable-R-shlib
web/checks
make
  /dcmeta
cd tests/Embedding
  /packages
make
  /views
~/R-3.0.1/bin/R CMD ./Rtest
</pre>


A clickable map [http://taichi.selfip.net:81/RmirrorMap/Rmirror.html]
nano embed.c
 
# Using a single line will give an error and cannot not show the real problem.
=== Bioconductor package download statistics ===
# ../../bin/R CMD gcc -I../../include -L../../lib -lR embed.c
http://bioconductor.org/packages/stats/
# A better way is to run compile and link separately
 
gcc -I../../include -c embed.c
=== Bioconductor repository directory structure ===
gcc -o embed embed.o -L../../lib -lR -lRblas
The information below is specific to Bioc 2.11 (R 2.15). There are linux and macosx subdirecotries whenever there are windows subdirectory.
../../bin/R CMD ./embed
<pre>
bioc/bin/windows/contrib/2.15
    /html
    /install
    /license
    /manuals
    /news
    /src
    /vignettes
data/annotation/bin/windows/contrib/2.15
              /html
              /licenses
              /manuals
              /src
              /vignettes
    /experiment/bin/windows/contrib/2.15
                /html
                /manuals
                /src/contrib
                /vignettes
extra/bin/windows/contrib
    /html
    /src
    /vignettes
</pre>
</pre>


=== List all R packages from CRAN/Bioconductor ===
Note that if we want to call the executable file ./embed directly, we shall set up R environment by specifying '''R_HOME''' variable and including the directories used in linking R in '''LD_LIBRARY_PATH'''. This is based on the inform provided by [http://cran.r-project.org/doc/manuals/r-devel/R-exts.html Writing R Extensions].
<s>
Check my daily result based on R 2.15 and Bioc 2.11 in [http://taichi.selfip.net:81/Rsummary/R_reposit.html]
 
# [http://taichi.selfip.net:81/Rsummary/cran.html CRAN]
# [http://taichi.selfip.net:81/Rsummary/bioc.html Bioc software]
# [http://taichi.selfip.net:81/Rsummary/annotation.html Bioc annotation]
# [http://taichi.selfip.net:81/Rsummary/experiment.html Bioc experiment]
</s>
 
See [http://www.r-pkg.org/pkglist METACRAN] for packages hosted on CRAN. The 'https://github.com/metacran/PACKAGES' file contains the latest update.
 
== r-hub: the everything-builder the R community needs ==
https://github.com/r-hub/proposal
 
== Parallel Computing ==
 
# [http://shop.oreilly.com/product/0636920021421.do Example code] for the book Parallel R by McCallum and Weston.
# [http://www.win-vector.com/blog/2016/01/parallel-computing-in-r/ A gentle introduction to parallel computing in R]
# [http://www.stat.berkeley.edu/scf/paciorek-distribComp.pdf An introduction to distributed memory parallelism in R and C]
# [http://danielmarcelino.com/parallel-processing/Parallel Processing: When does it worth?]
 
=== Windows Security Warning ===
It seems it is safe to choose 'Cancel' when Windows Firewall tried to block R program when we use '''makeCluster()''' to create a socket cluster.
<pre>
<pre>
library(parallel)
export R_HOME=/home/brb/Downloads/R-3.0.2
cl <- makeCluster(2)
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/brb/Downloads/R-3.0.2/lib
clusterApply(cl, 1:2, get("+"), 3)
./embed # No need to include R CMD in front.
stopCluster(cl)
</pre>
</pre>
[[File:WindowsSecurityAlert.png|100px]]


If we like to see current firewall settings, just click Windows Start button, search 'Firewall' and choose 'Windows Firewall with Advanced Security'. In the 'Inbound Rules', we can see what programs (like, R for Windows GUI front-end, or Rserve) are among the rules. These rules are called 'private' in the 'Profile' column. Note that each of them may appear twice because one is 'TCP' protocol and the other one has a 'UDP' protocol.
Question: Create a data frame in C? Answer: [https://stat.ethz.ch/pipermail/r-devel/2013-August/067107.html Use data.frame() via an eval() call from C]. Or see the code is stats/src/model.c, as part of model.frame.default. Or using Rcpp as [https://stat.ethz.ch/pipermail/r-devel/2013-August/067109.html here].


=== parallel package ===
Reference http://bioconductor.org/help/course-materials/2012/Seattle-Oct-2012/AdvancedR.pdf
Parallel package was included in R 2.14.0. It is derived from the snow and multicore packages and provides many of the same functions as those packages.


The parallel package provides several *apply functions for R users to quickly modify their code using parallel computing.
=== Create a Simple Socket Server in R ===
This example is coming from this [http://epub.ub.uni-muenchen.de/2085/1/tr012.pdf paper].  


* makeCluster(makePSOCKcluster, makeForkCluster), stopCluster. Other cluster types are passed to package '''snow'''.
Create an R function
* clusterCall, clusterEvalQ, clusterSplit
* clusterApply, clusterApplyLB
* clusterExport
* clusterMap
* parLapply, parSapply, parApply, parRapply, parCapply
* parLapplyLB, parSapplyLB (load balance version)
* clusterSetRNGStream, nextRNGStream, nextRNGSubStream
 
Examples (See ?[http://www.inside-r.org/r-doc/parallel/clusterApply clusterApply])
<pre>
<pre>
library(parallel)
simpleServer <- function(port=6543)
cl <- makeCluster(2, type = "SOCK")
{
clusterApply(cl, 1:2, function(x) x*3)   # OR clusterApply(cl, 1:2, get("*"), 3)
  sock <- socketConnection ( port=port , server=TRUE)
# [[1]]
  on.exit(close( sock ))
# [1] 3
  cat("\nWelcome to R!\nR>" ,file=sock )
#
  while(( line <- readLines ( sock , n=1)) != "quit")
# [[2]]
  {
# [1] 6
    cat(paste("socket >" , line , "\n"))
parSapply(cl, 1:20, get("+"), 3)
    out<- capture.output (try(eval(parse(text=line ))))
#  [1]  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
    writeLines ( out , con=sock )
stopCluster(cl)
    cat("\nR> " ,file =sock )
</pre>
  }
}
</pre>
Then run simpleServer(). Open another terminal and try to communicate with the server
<pre>
$ telnet localhost 6543
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.


=== [http://cran.r-project.org/web/packages/snow/index.html snow] package ===
Welcome to R!
R> summary(iris[, 3:5])
  Petal.Length    Petal.Width          Species 
Min.  :1.000  Min.  :0.100  setosa    :50 
1st Qu.:1.600  1st Qu.:0.300  versicolor:50 
Median :4.350  Median :1.300  virginica :50 
Mean  :3.758  Mean  :1.199                 
3rd Qu.:5.100  3rd Qu.:1.800                 
Max.  :6.900  Max.  :2.500                 


Supported cluster types are "SOCK", "PVM", "MPI", and "NWS".
R> quit
Connection closed by foreign host.
</pre>


=== [http://cran.r-project.org/web/packages/multicore/index.html multicore] package ===
=== [http://www.rforge.net/Rserve/doc.html Rserve] ===
This package is removed from CRAN.  
Note the way of launching Rserve is like the way we launch C program when R was embedded in C. See [[R#An_example_from_Bioconductor_workshop|Example from Bioconductor workshop]].


Consider using package ‘parallel’ instead.
See my [[Rserve]] page.


=== [http://cran.r-project.org/web/packages/foreach/index.html foreach] package ===
=== outsider ===
This package depends on one of the following
* [https://joss.theoj.org/papers/10.21105/joss.02038 outsider]: Install and run programs, outside of R, inside of R
* doParallel - Foreach parallel adaptor for the parallel package
* [https://github.com/stephenturner/om..bcftools Run bcftools with outsider in R]
* doSNOW - Foreach parallel adaptor for the snow package
* doMC - Foreach parallel adaptor for the multicore package
* doMPI - Foreach parallel adaptor for the Rmpi package
* doRedis - Foreach parallel adapter for the rredis package
as a backend.


<syntaxhighlight lang='rsplus'>
=== (Commercial) [http://www.statconn.com/ StatconnDcom] ===
library(foreach)
library(doParallel)


m <- matrix(rnorm(9), 3, 3)
=== [http://rdotnet.codeplex.com/ R.NET] ===


cl <- makeCluster(2, type = "SOCK")
=== [https://cran.r-project.org/web/packages/rJava/index.html rJava] ===
registerDoParallel(cl)
* [https://jozefhajnala.gitlab.io/r/r901-primer-java-from-r-1/ A primer in using Java from R - part 1]
foreach(i=1:nrow(m), .combine=rbind) %dopar%
* Note rJava is needed by [https://cran.r-project.org/web/packages/xlsx/index.html xlsx] package.
  (m[i,] / mean(m[i,]))


stopCluster(cl)
Terminal
</syntaxhighlight>
{{Pre}}
 
# jdk 7
See also this post [http://blog.revolutionanalytics.com/2015/10/updates-to-the-foreach-package-and-its-friends.html Updates to the foreach package and its friends] on Oct 2015.
sudo apt-get install openjdk-7-*
update-alternatives --config java
# oracle jdk 8
sudo add-apt-repository -y ppa:webupd8team/java
sudo apt-get update
echo debconf shared/accepted-oracle-license-v1-1 select true | sudo debconf-set-selections
echo debconf shared/accepted-oracle-license-v1-1 seen true | sudo debconf-set-selections
sudo apt-get -y install openjdk-8-jdk
</pre>
and then run the following (thanks to http://stackoverflow.com/questions/12872699/error-unable-to-load-installed-packages-just-now) to fix an error: libjvm.so: cannot open shared object file: No such file or directory.
* Create the file '''/etc/ld.so.conf.d/java.conf''' with the following entries:
<pre>
/usr/lib/jvm/java-8-oracle/jre/lib/amd64
/usr/lib/jvm/java-8-oracle/jre/lib/amd64/server
</pre>
* And then run '''sudo ldconfig'''


* [https://statcompute.wordpress.com/2015/12/13/calculate-leave-one-out-prediction-for-glm/ Cross validation in prediction for glm]
Now go back to R
{{Pre}}
install.packages("rJava")
</pre>
Done!


=== snowfall package ===
If above does not work, a simple way is by (under Ubuntu) running
http://www.imbi.uni-freiburg.de/parallel/docs/Reisensburg2009_TutParallelComputing_Knaus_Porzelius.pdf
<pre>
sudo apt-get install r-cran-rjava
</pre>
which will create new package 'default-jre' (under '''/usr/lib/jvm''') and 'default-jre-headless'.


=== [http://cran.r-project.org/web/packages/Rmpi/index.html Rmpi] package ===
=== RCaller ===
Some examples/tutorials


* http://trac.nchc.org.tw/grid/wiki/R-MPI_Install
=== RApache ===
* http://www.arc.vt.edu/resources/software/r/index.php
* http://www.stat.ucla.edu/~jeroen/files/seminar.pdf
* https://www.sharcnet.ca/help/index.php/Using_R_and_MPI
 
* http://math.acadiau.ca/ACMMaC/Rmpi/examples.html
=== Rscript, arguments and commandArgs() ===
* http://www.umbc.edu/hpcf/resources-tara/how-to-run-R.html
[https://www.r-bloggers.com/passing-arguments-to-an-r-script-from-command-lines/ Passing arguments to an R script from command lines]
* [http://www.slideshare.net/bytemining/taking-r-to-the-limit-high-performance-computing-in-r-part-1-parallelization-la-r-users-group-727 Ryan Rosario]
Syntax:
* http://pj.freefaculty.org/guides/Rcourse/parallel-1/parallel-1.pdf
<pre>
* * http://biowulf.nih.gov/apps/R.html
$ Rscript --help
Usage: /path/to/Rscript [--options] [-e expr [-e expr2 ...] | file] [args]
</pre>


=== OpenMP ===
Example:
* [http://www.parallelr.com/r-and-openmp-boosting-compiled-code-on-multi-core-cpu-s/ R and openMP: boosting compiled code on multi-core cpu-s] from parallelr.com.
<pre>
args = commandArgs(trailingOnly=TRUE)
# test if there is at least one argument: if not, return an error
if (length(args)==0) {
  stop("At least one argument must be supplied (input file).n", call.=FALSE)
} else if (length(args)==1) {
  # default output file
  args[2] = "out.txt"
}
cat("args[1] = ", args[1], "\n")
cat("args[2] = ", args[2], "\n")
</pre>
<pre>
Rscript --vanilla sillyScript.R iris.txt out.txt
# args[1] =  iris.txt
# args[2] =  out.txt
</pre>


=== [http://www.bioconductor.org/packages/release/bioc/html/BiocParallel.html BiocParallel] ===
=== Rscript, #! Shebang and optparse package ===
* [http://rpubs.com/seandavi/KallistoFromR Orchestrating a small, parallel, RNA-seq pre-processing workflow using R]
<ul>
<li>Writing [https://www.r-bloggers.com/2014/05/r-scripts/ R scripts] like linux bash files.
<li>[https://www.makeuseof.com/shebang-in-linux/ What Is the Shebang (#!) Character Sequence in Linux?]
<li>[https://blog.rmhogervorst.nl/blog/2020/04/14/where-does-the-output-of-rscript-go/ Where does the output of Rscript go?]
<li>Create a file <shebang.R>.
<pre>
#!/usr/bin/env Rscript
print ("shebang works")
</pre>
Then in the command line
<pre>
chmod u+x shebang.R
./shebang.R
</pre>
<li>[http://www.cureffi.org/2014/01/15/running-r-batch-mode-linux/ Running R in batch mode on Linux]
<li>[https://cran.r-project.org/web/packages/optparse/index.html optparse] package. Check out its vignette.
<li>[https://cran.r-project.org/web/packages/getopt/index.html getopt]: C-Like 'getopt' Behavior.
</ul>


=== [https://cran.r-project.org/web/packages/RcppParallel/index.html RcppParallel] ===
=== [http://dirk.eddelbuettel.com/code/littler.html littler] ===
Provides hash-bang (#!) capability for R


=== Apache Spark ===
FAQs:
* [http://files.meetup.com/3576292/Dubravko%20Dulic%20SparkR%20June%202016.pdf Introduction to Apache Spark]
* [http://stackoverflow.com/questions/3205302/difference-between-rscript-and-littler Difference between Rscript and littler]
* [https://stackoverflow.com/questions/3412911/r-exe-rcmd-exe-rscript-exe-and-rterm-exe-whats-the-difference Whats the difference between Rscript and R CMD BATCH]
* [https://stackoverflow.com/questions/21969145/why-or-when-is-rscript-or-littler-better-than-r-cmd-batch Why (or when) is Rscript (or littler) better than R CMD BATCH?]
{{Pre}}
root@ed5f80320266:/# ls -l /usr/bin/{r,R*}
# R 3.5.2 docker container
-rwxr-xr-x 1 root root 82632 Jan 26 18:26 /usr/bin/r        # binary, can be used for 'shebang' lines, r --help
                                              # Example: r --verbose -e "date()"


=== Microsoft R Server ===
-rwxr-xr-x 1 root root  8722 Dec 20 11:35 /usr/bin/R       # text, R --help
* [http://files.meetup.com/3576292/Stefan%20Cronjaeger%20R%20Server.pdf Microsoft R '''Server'''] (not Microsoft R Open)
                                              # Example: R -q -e "date()"


=== GPU ===
-rwxr-xr-x 1 root root 14552 Dec 20 11:35 /usr/bin/Rscript  # binary, can be used for 'shebang' lines, Rscript --help
* [http://www.parallelr.com/r-gpu-programming-for-all-with-gpur/ GPU Programming for All with ‘gpuR] from parallelr.com. The gpuR is available on [https://cran.r-project.org/web/packages/gpuR/index.html CRAN].
                                              # It won't show the startup message when it is used in the command line.
* [https://cran.r-project.org/web/packages/gputools/index.html gputools]
                                              # Example: Rscript -e "date()"
</pre>


== Cloud Computing ==
We can install littler using two ways.
* install.packages("littler"). This will install the latest version but the binary 'r' program is only available under the package/bin directory (eg ''~/R/x86_64-pc-linux-gnu-library/3.4/littler/bin/r''). You need to create a soft link in order to access it globally.
* sudo apt install littler. This will install 'r' globally; however, the installed version may be old.


=== Install R on Amazon EC2 ===
After the installation, vignette contains several examples. The off-line vignette has a table of contents. Nice! The [http://dirk.eddelbuettel.com/code/littler.examples.html web version of examples] does not have the TOC.
http://randyzwitch.com/r-amazon-ec2/


=== Bioconductor on Amazon EC2 ===
'''r''' was not meant to run interactively like '''R'''. See ''man r''.
http://www.bioconductor.org/help/bioconductor-cloud-ami/


== Big Data Analysis ==
=== RInside: Embed R in C++ ===
http://blog.comsysto.com/2013/02/14/my-favorite-community-links/
See [[R#RInside|RInside]]


== Useful R packages ==
(''From RInside documentation'') The RInside package makes it easier to embed R in your C++ applications. There is no code you would execute directly from the R environment. Rather, you write C++ programs that embed R which is illustrated by some the included examples.
* [https://github.com/qinwf/awesome-R awesome-R]


=== RInside ===
The included examples are armadillo, eigen, mpi, qt, standard, threads and wt.
* http://dirk.eddelbuettel.com/code/rinside.html
* http://dirk.eddelbuettel.com/papers/rfinance2010_rcpp_rinside_tutorial_handout.pdf


==== Ubuntu ====
To run 'make' when we don't have a global R, we should modify the file <Makefile>. Also if we just want to create one executable file, we can do, for example, 'make rinside_sample1'.
With RInside, R can be embedded in a graphical application. For example, $HOME/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/qt directory includes source code of a Qt application to show a kernel density plot with various options like kernel functions, bandwidth and an R command text box to generate the random data. See my demo on [http://www.youtube.com/watch?v=UQ8yKQcPTg0 Youtube]. I have tested this '''qtdensity''' example successfully using Qt 4.8.5.
# Follow the instruction [[#cairoDevice|cairoDevice]] to install required libraries for cairoDevice package and then cairoDevice itself.
# Install [[Qt|Qt]]. Check 'qmake' command becomes available by typing 'whereis qmake' or 'which qmake' in terminal.
# Open Qt Creator from Ubuntu start menu/Launcher. Open the project file $HOME/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/qt/qtdensity.pro in Qt Creator.
# Under Qt Creator, hit 'Ctrl + R' or the big green triangle button on the lower-left corner to build/run the project. If everything works well, you shall see the ''interactive'' program qtdensity appears on your desktop.
[[File:qtdensity.png|100px]].


With RInside + [http://www.webtoolkit.eu/wt Wt web toolkit] installed, we can also create a web application. To demonstrate the example in ''examples/wt'' directory, we can do
To run any executable program, we need to specify '''LD_LIBRARY_PATH''' variable, something like
<pre>
<pre>export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/brb/Downloads/R-3.0.2/lib </pre>
cd ~/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/wt
make
sudo ./wtdensity --docroot . --http-address localhost --http-port 8080
</pre>
Then we can go to the browser's address bar and type ''http://localhost:8080'' to see how it works (a screenshot is in [http://dirk.eddelbuettel.com/blog/2011/11/30/ here]).


==== Windows 7 ====
The real build process looks like (check <Makefile> for completeness)
To make RInside works on Windows OS, try the following
# Make sure R is installed under '''C:\''' instead of '''C:\Program Files''' if we don't want to get an error like ''g++.exe: error: Files/R/R-3.0.1/library/RInside/include: No such file or directory''.
# Install RTools
# Instal RInside package from source (the binary version will give an [http://stackoverflow.com/questions/13137770/fatal-error-unable-to-open-the-base-package error ])
# Create a DOS batch file containing necessary paths in PATH environment variable
<pre>
<pre>
@echo off
g++ -I/home/brb/Downloads/R-3.0.2/include \
set PATH=C:\Rtools\bin;c:\Rtools\gcc-4.6.3\bin;%PATH%
    -I/home/brb/Downloads/R-3.0.2/library/Rcpp/include \
set PATH=C:\R\R-3.0.1\bin\i386;%PATH%
    -I/home/brb/Downloads/R-3.0.2/library/RInside/include -g -O2 -Wall \
set PKG_LIBS=`Rscript -e "Rcpp:::LdFlags()"`
    -I/usr/local/include  \
set PKG_CPPFLAGS=`Rscript -e "Rcpp:::CxxFlags()"`
    rinside_sample0.cpp  \
set R_HOME=C:\R\R-3.0.1
    -L/home/brb/Downloads/R-3.0.2/lib -lR  -lRblas -lRlapack \
echo Setting environment for using R
    -L/home/brb/Downloads/R-3.0.2/library/Rcpp/lib -lRcpp \
cmd
    -Wl,-rpath,/home/brb/Downloads/R-3.0.2/library/Rcpp/lib \
    -L/home/brb/Downloads/R-3.0.2/library/RInside/lib -lRInside \
    -Wl,-rpath,/home/brb/Downloads/R-3.0.2/library/RInside/lib \
    -o rinside_sample0
</pre>
</pre>
In the Windows command prompt, run
 
Hello World example of embedding R in C++.
<pre>
<pre>
cd C:\R\R-3.0.1\library\RInside\examples\standard
#include <RInside.h>                    // for the embedded R via RInside
make -f Makefile.win
 
</pre>
int main(int argc, char *argv[]) {
Now we can test by running any of executable files that '''make''' generates. For example, ''rinside_sample0''.
 
<pre>
    RInside R(argc, argv);              // create an embedded R instance
rinside_sample0
</pre>


As for the Qt application qdensity program, we need to make sure the same version of MinGW was used in building RInside/Rcpp and Qt. See  some discussions in
    R["txt"] = "Hello, world!\n"; // assign a char* (string) to 'txt'
* http://stackoverflow.com/questions/12280707/using-rinside-with-qt-in-windows
* http://www.mail-archive.com/[email protected]/msg04377.html
So the Qt and Wt web tool applications on Windows may or may not be possible.


=== GUI ===
    R.parseEvalQ("cat(txt)");          // eval the init string, ignoring any returns
==== Qt and R ====
* http://cran.r-project.org/web/packages/qtbase/index.html [https://stat.ethz.ch/pipermail/r-devel/2015-July/071495.html QtDesigner is such a tool, and its output is compatible with the qtbase R package]
* http://qtinterfaces.r-forge.r-project.org


=== tkrplot ===
    exit(0);
On Ubuntu, we need to install tk packages, such as by
}
<pre>
sudo apt-get install tk-dev
</pre>
</pre>


=== Hadoop (eg ~100 terabytes) ===
The above can be compared to the Hello world example in Qt.
See also [http://cran.r-project.org/web/views/HighPerformanceComputing.html HighPerformanceComputing]
<pre>
#include <QApplication.h>
#include <QPushButton.h>


* RHadoop
int main( int argc, char **argv )
* Hive
{
* [http://cran.r-project.org/web/packages/mapReduce/ MapReduce]. Introduction by [http://www.linuxjournal.com/content/introduction-mapreduce-hadoop-linux Linux Journal].
    QApplication app( argc, argv );
* http://www.techspritz.com/category/tutorials/hadoopmapredcue/ Single node or multinode cluster setup using Ubuntu with VirtualBox (Excellent)
* [http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/ Running Hadoop on Ubuntu Linux (Single-Node Cluster)]
* Ubuntu 12.04 http://www.youtube.com/watch?v=WN2tJk_oL6E and [https://www.dropbox.com/s/05aurcp42asuktp/Chiu%20Hadoop%20Pig%20Install%20Instructions.docx instruction]
* Linux Mint http://blog.hackedexistence.com/installing-hadoop-single-node-on-linux-mint
* http://www.r-bloggers.com/search/hadoop


==== [https://github.com/RevolutionAnalytics/RHadoop/wiki RHadoop] ====
    QPushButton hello( "Hello world!", 0 );
* [http://www.rdatamining.com/tutorials/r-hadoop-setup-guide RDataMining.com] based on Mac.
    hello.resize( 100, 30 );
* Ubuntu 12.04 - [http://crishantha.com/wp/?p=1414 Crishantha.com], [http://nikhilshah123sh.blogspot.com/2014/03/setting-up-rhadoop-in-ubuntu-1204.html nikhilshah123sh.blogspot.com].[http://bighadoop.wordpress.com/2013/02/25/r-and-hadoop-data-analysis-rhadoop/ Bighadoop.wordpress] contains an example.
* RapReduce in R by [https://github.com/RevolutionAnalytics/rmr2/blob/master/docs/tutorial.md RevolutionAnalytics] with a few examples.
* https://twitter.com/hashtag/rhadoop
* [http://bigd8ta.com/step-by-step-guide-to-setting-up-an-r-hadoop-system/ Bigd8ta.com] based on Ubuntu 14.04.


==== Snowdoop: an alternative to MapReduce algorithm ====
    app.setMainWidget( &hello );
* http://matloff.wordpress.com/2014/11/26/how-about-a-snowdoop-package/
    hello.show();
* http://matloff.wordpress.com/2014/12/26/snowdooppartools-update/comment-page-1/#comment-665


=== [http://cran.r-project.org/web/packages/XML/index.html XML] ===
    return app.exec();
On Ubuntu, we need to install libxml2-dev before we can install XML package.
}
<pre>
sudo apt-get update
sudo apt-get install libxml2-dev
</pre>
</pre>


On CentOS,
=== [http://www.rfortran.org/ RFortran] ===
<pre>
RFortran is an open source project with the following aim:
yum -y install libxml2 libxml2-devel
 
</pre>
''To provide an easy to use Fortran software library that enables Fortran programs to transfer data and commands to and from R.''


==== xmlview ====
It works only on Windows platform with Microsoft Visual Studio installed:(
* http://rud.is/b/2016/01/13/cobble-xpath-interactively-with-the-xmlview-package/


=== RCurl ===
== Call R from other languages ==
On Ubuntu, we need to install the packages (the first one is for XML package that RCurl suggests)
=== C ===
<syntaxhighlight lang='bash'>
[http://sebastian-mader.net/programming/using-r-from-c-c/ Using R from C/C++]
# Test on Ubuntu 14.04
sudo apt-get install libxml2-dev
sudo apt-get install libcurl4-openssl-dev
</syntaxhighlight>


==== [https://github.com/hadley/httr httr] ====
Error: [https://stackoverflow.com/questions/43662542/not-resolved-from-current-namespace-error-when-calling-c-routines-from-r “not resolved from current namespace” error, when calling C routines from R]
httr imports curl, jsonlite, mime, openssl and R6 packages.


When I tried to install httr package, I got an error and some message:
Solution: add '''getNativeSymbolInfo()''' around your C/Fortran symbols. Search Google:r dyn.load not resolved from current namespace
<pre>
 
Configuration failed because openssl was not found. Try installing:
=== JRI ===
* deb: libssl-dev (Debian, Ubuntu, etc)
http://www.rforge.net/JRI/
* rpm: openssl-devel (Fedora, CentOS, RHEL)
* csw: libssl_dev (Solaris)
* brew: openssl (Mac OSX)
If openssl is already installed, check that 'pkg-config' is in your
PATH and PKG_CONFIG_PATH contains a openssl.pc file. If pkg-config
is unavailable you can set INCLUDE_DIR and LIB_DIR manually via:
R CMD INSTALL --configure-vars='INCLUDE_DIR=... LIB_DIR=...'
--------------------------------------------------------------------
ERROR: configuration failed for package ‘openssl’
</pre>
It turns out after I run '''sudo apt-get install libssl-dev''' in the terminal (Debian), it would go smoothly with installing httr package. Nice httr!


Real example: see [http://stackoverflow.com/questions/27371372/httr-retrieving-data-with-post this post]. Unfortunately I did not get a table result; I only get an html file (R 3.2.5, httr 1.1.0 on Ubuntu and Debian).
=== ryp2 ===
http://rpy.sourceforge.net/rpy2.html


Since httr package was used in many other packages, take a look at how others use it. For example, [https://github.com/ropensci/aRxiv aRxiv] package.
== Create a standalone Rmath library ==
R has many math and statistical functions. We can easily use these functions in our C/C++/Fortran. The definite guide of doing this is on Chapter 9 "The standalone Rmath library" of [http://cran.r-project.org/doc/manuals/R-admin.html#The-standalone-Rmath-library R-admin manual].


==== [http://cran.r-project.org/web/packages/curl/ curl] ====
Here is my experience based on R 3.0.2 on Windows OS.
curl is independent of RCurl package.


* http://cran.r-project.org/web/packages/curl/vignettes/intro.html
=== Create a static library <libRmath.a> and a dynamic library <Rmath.dll> ===
* https://www.opencpu.org/posts/curl-release-0-8/
Suppose we have downloaded R source code and build R from its source. See [[R#Build_R_from_its_source|Build_R_from_its_source]]. Then the following 2 lines will generate files <libRmath.a> and <Rmath.dll> under C:\R\R-3.0.2\src\nmath\standalone directory.
<pre>
cd C:\R\R-3.0.2\src\nmath\standalone
make -f Makefile.win
</pre>


<syntaxhighlight lang='rsplus'>
=== Use Rmath library in our code ===
library(curl)
<pre>
h <- new_handle()
set CPLUS_INCLUDE_PATH=C:\R\R-3.0.2\src\include
handle_setform(h,
set LIBRARY_PATH=C:\R\R-3.0.2\src\nmath\standalone
  name="aaa", email="bbb"
# It is not LD_LIBRARY_PATH in above.
)
 
req <- curl_fetch_memory("http://localhost/d/phpmyql3_scripts/ch02/form2.html", handle = h)
# Created <RmathEx1.cpp> from the book "Statistical Computing in C++ and R" web site
rawToChar(req$content)
# http://math.la.asu.edu/~eubank/CandR/ch4Code.cpp
</syntaxhighlight>
# It is OK to save the cpp file under any directory.


==== [http://ropensci.org/packages/index.html rOpenSci] packages ====
# Force to link against the static library <libRmath.a>
'''rOpenSci''' contains packages that allow access to data repositories through the R statistical programming environment
g++ RmathEx1.cpp -lRmath -lm -o RmathEx1.exe
# OR
g++ RmathEx1.cpp -Wl,-Bstatic -lRmath -lm -o RmathEx1.exe


=== DirichletMultinomial ===
# Force to link against dynamic library <Rmath.dll>
On Ubuntu, we do
g++ RmathEx1.cpp Rmath.dll -lm -o RmathEx1Dll.exe
</pre>
Test the executable program. Note that the executable program ''RmathEx1.exe'' can be transferred to and run in another computer without R installed. Isn't it cool!
<pre>
<pre>
sudo apt-get install libgsl0-dev
c:\R>RmathEx1
Enter a argument for the normal cdf:
1
Enter a argument for the chi-squared cdf:
1
Prob(Z <= 1) = 0.841345
Prob(Chi^2 <= 1)= 0.682689
</pre>
</pre>


=== Create GUI ===
Below is the cpp program <RmathEx1.cpp>.
==== [http://cran.r-project.org/web/packages/gWidgets/index.html gWidgets] ====
<pre>
//RmathEx1.cpp
#define MATHLIB_STANDALONE
#include <iostream>
#include "Rmath.h"


=== [http://cran.r-project.org/web/packages/GenOrd/index.html GenOrd]: Generate ordinal and discrete variables with given correlation matrix and marginal distributions ===
using std::cout; using std::cin; using std::endl;
[http://statistical-research.com/simulating-random-multivariate-correlated-data-categorical-variables/?utm_source=rss&utm_medium=rss&utm_campaign=simulating-random-multivariate-correlated-data-categorical-variables here]


=== [http://cran.r-project.org/web/packages/rjson/index.html rjson] ===
int main()
http://heuristically.wordpress.com/2013/05/20/geolocate-ip-addresses-in-r/
{
  double x1, x2;
  cout << "Enter a argument for the normal cdf:" << endl;
  cin >> x1;
  cout << "Enter a argument for the chi-squared cdf:" << endl;
  cin >> x2;


=== [http://cran.r-project.org/web/packages/RJSONIO/index.html RJSONIO] ===
  cout << "Prob(Z <= " << x1 << ") = " <<
==== Accessing Bitcoin Data with R ====
    pnorm(x1, 0, 1, 1, 0)  << endl;
http://blog.revolutionanalytics.com/2015/11/accessing-bitcoin-data-with-r.html
  cout << "Prob(Chi^2 <= " << x2 << ")= " <<
    pchisq(x2, 1, 1, 0) << endl;
  return 0;
}
</pre>


==== Plot IP on google map ====
== Calling R.dll directly ==
* http://thebiobucket.blogspot.com/2011/12/some-fun-with-googlevis-plotting-blog.html#more  (RCurl, RJONIO, plyr, googleVis)
See Chapter 8.2.2 of [http://cran.r-project.org/doc/manuals/R-exts.html#Calling-R_002edll-directly|Writing R Extensions]. This is related to embedding R under Windows. The file <R.dll> on Windows is like <libR.so> on Linux.
* http://devblog.icans-gmbh.com/using-the-maxmind-geoip-api-with-r/ (RCurl, RJONIO, maps)
* http://cran.r-project.org/web/packages/geoPlot/index.html (geoPlot package (deprecated as 8/12/2013))
* http://archive09.linux.com/feature/135384  (Not R) ApacheMap
* http://batchgeo.com/features/geolocation-ip-lookup/    (Not R)  (Enter a spreadsheet of adress, city, zip or a column of IPs and it will show the location on google map)
* http://code.google.com/p/apachegeomap/


The following example is modified from the first of above list.
== Create HTML report ==
<pre>
[http://www.bioconductor.org/packages/release/bioc/html/ReportingTools.html ReportingTools] (Jason Hackney) from Bioconductor. See [[Genome#ReportingTools|Genome->ReportingTools]].
require(RJSONIO) # fromJSON
require(RCurl)  # getURL


temp = getURL("https://gist.github.com/arraytools/6743826/raw/23c8b0bc4b8f0d1bfe1c2fad985ca2e091aeb916/ip.txt",
=== [http://cran.r-project.org/web/packages/htmlTable/index.html htmlTable] package ===
                          ssl.verifypeer = FALSE)
The htmlTable package is intended for generating tables using HTML formatting. This format is compatible with Markdown when used for HTML-output. The most basic table can easily be created by just passing a matrix or a data.frame to the htmlTable-function.
ip <- read.table(textConnection(temp), as.is=TRUE)
names(ip) <- "IP"
nr = nrow(ip)
Lon <- as.numeric(rep(NA, nr))
Lat <- Lon
Coords <- data.frame(Lon, Lat)
ip2coordinates <- function(ip) {
  api <- "http://freegeoip.net/json/"
  get.ips <- getURL(paste(api, URLencode(ip), sep=""))
  # result <- ldply(fromJSON(get.ips), data.frame)
  result <- data.frame(fromJSON(get.ips))
  names(result)[1] <- "ip.address"
  return(result)
}


for (i in 1:nr){
* http://cran.r-project.org/web/packages/htmlTable/vignettes/general.html
  cat(i, "\n")
* http://gforge.se/2014/01/fast-track-publishing-using-knitr-part-iv/
  try(
* [http://gforge.se/2020/07/news-in-htmltable-2-0/ News in htmlTable 2.0]
  Coords[i, 1:2] <- ip2coordinates(ip$IP[i])[c("longitude", "latitude")]
  )
}
# append to log-file:
logfile <- data.frame(ip, Lat = Coords$Lat, Long = Coords$Lon,
                                      LatLong = paste(round(Coords$Lat, 1), round(Coords$Lon, 1), sep = ":"))
log_gmap <- logfile[!is.na(logfile$Lat), ]


require(googleVis) # gvisMap
=== [https://cran.r-project.org/web/packages/formattable/index.html formattable] ===
gmap <- gvisMap(log_gmap, "LatLong",
* https://github.com/renkun-ken/formattable
                options = list(showTip = TRUE, enableScrollWheel = TRUE,
* http://www.magesblog.com/2016/01/formatting-table-output-in-r.html
                              mapType = 'hybrid', useMapTypeControl = TRUE,
* [https://www.displayr.com/formattable/ Make Beautiful Tables with the Formattable Package]
                              width = 1024, height = 800))
plot(gmap)
</pre>
[[File:GoogleVis.png|200px]]


The plot.gvis() method in googleVis packages also teaches the startDynamicHelp() function in the tools package, which was used to launch a http server. See
=== [https://github.com/crubba/htmltab htmltab] package ===
[http://jeffreyhorner.tumblr.com/page/3 Jeffrey Horner's note about deploying Rook App].
This package is NOT used to CREATE html report but EXTRACT html table.


=== Map ===
=== [http://cran.r-project.org/web/packages/ztable/index.html ztable] package ===
==== [https://rstudio.github.io/leaflet/ leaflet] ====
Makes zebra-striped tables (tables with alternating row colors) in LaTeX and HTML formats easily from a data.frame, matrix, lm, aov, anova, glm or coxph objects.
* rstudio.github.io/leaflet/#installation-and-use
* https://metvurst.wordpress.com/2015/07/24/mapview-basic-interactive-viewing-of-spatial-data-in-r-6/


==== choroplethr ====
== Create academic report ==
* http://blog.revolutionanalytics.com/2014/01/easy-data-maps-with-r-the-choroplethr-package-.html
[http://cran.r-project.org/web/packages/reports/index.html reports] package in CRAN and in [https://github.com/trinker/reports github] repository. The youtube video gives an overview of the package.
* http://www.arilamstein.com/blog/2015/06/25/learn-to-map-census-data-in-r/
* http://www.arilamstein.com/blog/2015/09/10/user-question-how-to-add-a-state-border-to-a-zip-code-map/


=== [http://cran.r-project.org/web/packages/googleVis/index.html googleVis] ===
== Create pdf and epub files ==
See an example from [[R#RJSONIO|RJSONIO]] above.
{{Pre}}
# Idea:
#        knitr        pdflatex
#  rnw -------> tex ----------> pdf
library(knitr)
knit("example.rnw") # create example.tex file
</pre>
* A very simple example <002-minimal.Rnw> from [http://yihui.name/knitr/demo/minimal/ yihui.name] works fine on linux.
{{Pre}}
git clone https://github.com/yihui/knitr-examples.git
</pre>
* <knitr-minimal.Rnw>. I have no problem to create pdf file on Windows but still cannot generate pdf on Linux from tex file. Some people suggested to run '''sudo apt-get install texlive-fonts-recommended''' to install missing fonts. It works!


=== [https://cran.r-project.org/web/packages/googleAuthR/index.html googleAuthR] ===
To see a real example, check out [http://www.bioconductor.org/packages/release/bioc/html/DESeq2.html DESeq2] package (inst/doc subdirectory). In addition to DESeq2, I also need to install '''DESeq, BiocStyle, airway, vsn, gplots''', and '''pasilla''' packages from Bioconductor. Note that, it is best to use sudo/admin account to install packages.
Create R functions that interact with OAuth2 Google APIs easily, with auto-refresh and Shiny compatibility.


=== gtrendsR ===
Or starts with markdown file. Download the example <001-minimal.Rmd> and remove the last line of getting png file from internet.
[http://blog.revolutionanalytics.com/2015/12/download-and-plot-google-trends-data-with-r.html Download and plot Google Trends data with R]
{{Pre}}
# Idea:
#        knitr        pandoc
#  rmd -------> md ----------> pdf


=== quantmod ===
git clone https://github.com/yihui/knitr-examples.git
[http://www.thertrader.com/2015/12/13/maintaining-a-database-of-price-files-in-r/ Maintaining a database of price files in R]. It consists of 3 steps.
cd knitr-examples
R -e "library(knitr); knit('001-minimal.Rmd')"
pandoc 001-minimal.md -o 001-minimal.pdf # require pdflatex to be installed !!
</pre>


# Initial data downloading
To create an epub file (not success yet on Windows OS, missing figures on Linux OS)
# Update existing data
{{Pre}}
# Create a batch file
# Idea:
#       knitr        pandoc
#   rnw -------> tex ----------> markdown or epub


=== [http://cran.r-project.org/web/packages/Rcpp/index.html Rcpp] ===
library(knitr)
knit("DESeq2.Rnw") # create DESeq2.tex
system("pandoc  -f latex -t markdown -o DESeq2.md DESeq2.tex")
</pre>


[http://lists.r-forge.r-project.org/pipermail/rcpp-devel/ Discussion archive]
Convert tex to epub
* http://tex.stackexchange.com/questions/156668/tex-to-epub-conversion


==== Speed Comparison ====
=== [https://www.rdocumentation.org/packages/knitr/versions/1.20/topics/kable kable()] for tables ===
* [http://blog.revolutionanalytics.com/2015/06/a-comparison-of-high-performance-computing-techniques-in-r.html A comparison of high-performance computing techniques in R]. It compares Rcpp to an R looping operator (like mapply), a parallelized version of a looping operator (like mcmapply), explicit parallelization, via the parallel package or the ParallelR suite.
Create Tables In LaTeX, HTML, Markdown And ReStructuredText
* In the following example, C++ avoids the overhead of creating an intermediate object (eg vector of the same length as the original vector). The c++ uses an intermediate scalar. So C++ wins R over memory management in this case.
<syntaxhighlight lang='rsplus'>
# http://blog.mckuhn.de/2016/03/avoiding-unnecessary-memory-allocations.html
library(Rcpp)


`%count<%` <- cppFunction('
* https://rmarkdown.rstudio.com/lesson-7.html
size_t count_less(NumericVector x, NumericVector y) {
* https://stackoverflow.com/questions/20942466/creating-good-kable-output-in-rstudio
  const size_t nx = x.size();
* http://kbroman.org/knitr_knutshell/pages/figs_tables.html
  const size_t ny = y.size();
* https://blogs.reed.edu/ed-tech/2015/10/creating-nice-tables-using-r-markdown/
  if (nx > 1 & ny > 1) stop("Only one parameter can be a vector!");
* [https://cran.r-project.org/web/packages/kableExtra/vignettes/awesome_table_in_html.html kableExtra] package
  size_t count = 0;
  if (nx == 1) {
    double c = x[0];
    for (int i = 0; i < ny; i++) count += c < y[i];
  } else {
    double c = y[0];
    for (int i = 0; i < nx; i++) count += x[i] < c;
  }
  return count;
}
')


set.seed(42)
== Create Word report ==


N <- 10^7
=== Using the power of Word ===
v <- runif(N, 0, 10000)
[https://www.rforecology.com/post/exporting-tables-from-r-to-microsoft-word/ How to go from R to nice tables in Microsoft Word]


# Testing on my ODroid xu4 running ubuntu 15.10
=== knitr + pandoc ===
system.time(sum(v < 5000))
* http://www.r-statistics.com/2013/03/write-ms-word-document-using-r-with-as-little-overhead-as-possible/
#  user  system elapsed
* http://www.carlboettiger.info/2012/04/07/writing-reproducibly-in-the-open-with-knitr.html
#  1.135  0.305  1.453
* http://rmarkdown.rstudio.com/articles_docx.html
system.time(v %count<% 5000)
#  user  system elapsed
#  0.535  0.000  0.540
</syntaxhighlight>


==== Use Rcpp in RStudio ====
It is better to create rmd file in RStudio. Rstudio provides a template for rmd file and it also provides a quick reference to R markdown language.
RStudio makes it easy to use Rcpp package.
 
Open RStudio, click New File -> C++ File. It will create a C++ template on the RStudio editor
<pre>
<pre>
#include <Rcpp.h>
# Idea:
using namespace Rcpp;
#        knitr      pandoc
 
#  rmd -------> md --------> docx
// Below is a simple example of exporting a C++ function to R. You can
library(knitr)
// source this function into an R session using the Rcpp::sourceCpp
knit2html("example.rmd") #Create md and html files
// function (or via the Source button on the editor toolbar)
 
// For more on using Rcpp click the Help button on the editor toolbar
 
// [[Rcpp::export]]
int timesTwo(int x) {
  return x * 2;
}
</pre>
</pre>
Now in R console, type
and then
<pre>
<pre>
library(Rcpp)
FILE <- "example"
sourceCpp("~/Downloads/timesTwo.cpp")
system(paste0("pandoc -o ", FILE, ".docx ", FILE, ".md"))
timesTwo(9)
# [1] 18
</pre>
</pre>
See more examples on http://adv-r.had.co.nz/Rcpp.html.
Note. For example reason, if I play around the above 2 commands for several times, the knit2html() does not work well. However, if I click 'Knit HTML' button on the RStudio, it then works again.


If we wan to test Boost library, we can try it in RStudio. Consider the following example in [http://stackoverflow.com/questions/19034564/can-the-bh-r-package-link-to-boost-math-and-numeric stackoverflow.com].
Another way is
<pre>
<pre>
// [[Rcpp::depends(BH)]]
library(pander)
#include <Rcpp.h>
name = "demo"
#include <boost/foreach.hpp>
knit(paste0(name, ".Rmd"), encoding = "utf-8")
#include <boost/math/special_functions/gamma.hpp>
Pandoc.brew(file = paste0(name, ".md"), output = paste0(-name, "docx"), convert = "docx")
</pre>


#define foreach BOOST_FOREACH
Note that once we have used knitr command to create a md file, we can use pandoc shell command to convert it to different formats:
* A pdf file: pandoc -s report.md -t latex -o report.pdf
* A html file: pandoc -s report.md -o report.html (with the -c flag html files can be added easily)
* Openoffice: pandoc report.md -o report.odt
* Word docx: pandoc report.md -o report.docx


using namespace boost::math;
We can also create the epub file for reading on Kobo ereader. For example, download [https://gist.github.com/jeromyanglim/2716336 this file] and save it as example.Rmd. I need to remove the line containing the link to http://i.imgur.com/RVNmr.jpg since it creates an error when I run pandoc (not sure if it is the pandoc version I have is too old). Now we just run these 2 lines to get the epub file. Amazing!
 
//[[Rcpp::export]]
Rcpp::NumericVector boost_gamma( Rcpp::NumericVector x ) {
  foreach( double& elem, x ) {
    elem = boost::math::tgamma(elem);
  };
 
  return x;
}
</pre>
Then the R console
<pre>
<pre>
boost_gamma(0:10 + 1)
knit("example.Rmd")
#  [1]      1      1      2      6      24    120    720    5040  40320
pandoc("example.md", format="epub")
# [10]  362880 3628800
 
identical( boost_gamma(0:10 + 1), factorial(0:10) )
# [1] TRUE
</pre>
</pre>


==== Example 1. convolution example ====
PS. If we don't remove the link, we will get an error message (pandoc 1.10.1 on Windows 7)
First, Rcpp package should be installed (I am working on Linux system). Next we try one example shipped in Rcpp package.
 
PS. If R was not available in global environment (such as built by ourselves), we need to modify 'Makefile' file by replacing 'R' command with its complete path (4 places).
<pre>
<pre>
cd ~/R/x86_64-pc-linux-gnu-library/3.0/Rcpp/examples/ConvolveBenchmarks/
> pandoc("Rmd_to_Epub.md", format="epub")
make
executing pandoc  -f markdown -t epub -o Rmd_to_Epub.epub "Rmd_to_Epub.utf8md"
R
pandoc.exe: .\.\http://i.imgur.com/RVNmr.jpg: openBinaryFile: invalid argument (Invalid argument)
</pre>
Error in (function (input, format, ext, cfg) : conversion failed
Then type the following in an R session to see how it works. Note that we don't need to issue '''library(Rcpp)''' in R.
In addition: Warning message:
<pre>
running command 'pandoc  -f markdown -t epub -o Rmd_to_Epub.epub "Rmd_to_Epub.utf8md"' had status 1
dyn.load("convolve3_cpp.so")
x <- .Call("convolve3cpp", 1:3, 4:6)
x # 4 13 28 27 18
</pre>
</pre>


If we have our own cpp file, we need to use the following way to create dynamic loaded library file. Note that the  character ([http://bash.cyberciti.biz/guide/Command_substitution grave accent]) ` is not (single quote)'. If you mistakenly use ', it won't work.
=== pander ===
<pre>
Try pandoc[1] with a minimal reproducible example, you might give a try to my "[http://cran.r-project.org/web/packages/pander/ pander]" package [2] too:
export PKG_CXXFLAGS=`Rscript -e "Rcpp:::CxxFlags()"`
export PKG_LIBS=`Rscript -e "Rcpp:::LdFlags()"`
R CMD SHLIB xxxx.cpp
</pre>


==== Example 2. Use together with inline package ====
* http://adv-r.had.co.nz/C-interface.html#calling-c-functions-from-r
<pre>
<pre>
library(inline)
library(pander)
src <-'
Pandoc.brew(system.file('examples/minimal.brew', package='pander'),
Rcpp::NumericVector xa(a);
            output = tempfile(), convert = 'docx')
Rcpp::NumericVector xb(b);
int n_xa = xa.size(), n_xb = xb.size();
 
Rcpp::NumericVector xab(n_xa + n_xb - 1);
for (int i = 0; i < n_xa; i++)
for (int j = 0; j < n_xb; j++)
xab[i + j] += xa[i] * xb[j];
return xab;
'
fun <- cxxfunction(signature(a = "numeric", b = "numeric"),
src, plugin = "Rcpp")
fun(1:3, 1:4)  
# [1]  1  4 10 16 17 12
</pre>
</pre>
Where the content of the "minimal.brew" file is something you might have
got used to with Sweave - although it's using "brew" syntax instead. See
the examples of pander [3] for more details. Please note that pandoc should
be installed first, which is pretty easy on Windows.


==== Example 3. Calling an R function ====
# http://johnmacfarlane.net/pandoc/
# http://rapporter.github.com/pander/
# http://rapporter.github.com/pander/#examples


==== [http://cran.r-project.org/web/packages/RcppParallel/index.html RcppParallel] ====
=== R2wd ===
Use [http://cran.r-project.org/web/packages/R2wd/ R2wd] package. However, only 32-bit R is allowed and sometimes it can not produce all 'table's.
<pre>
> library(R2wd)
> wdGet()
Loading required package: rcom
Loading required package: rscproxy
rcom requires a current version of statconnDCOM installed.
To install statconnDCOM type
    installstatconnDCOM()
 
This will download and install the current version of statconnDCOM


=== [http://cran.r-project.org/web/packages/caret/index.html caret] ===
You will need a working Internet connection
because installation needs to download a file.
Error in if (wdapp[["Documents"]][["Count"]] == 0) wdapp[["Documents"]]$Add() :  
  argument is of length zero
</pre>


=== Read/Write Excel files package ===
The solution is to launch 32-bit R instead of 64-bit R since statconnDCOM does not support 64-bit R.
* [http://cran.r-project.org/web/packages/xlsx/index.html xlsx]: depends on Java
* [http://cran.r-project.org/web/packages/openxlsx/index.html openxlsx]: not depend on Java. Depend on zip application. On Windows, it seems to be OK without installing Rtools. But it can not read xls file; it works on xlsx file.
* [https://github.com/hadley/readxl readxl]: it does not depend on anything although it can only read but not write Excel files. Tested it on Ubuntu machine with R 3.1.3 using <BRCA.xls> file. Usage:
<syntaxhighlight lang='rsplus'>
read_excel(path, sheet = 1, col_names = TRUE, col_types = NULL, na = "", skip = 0)
</syntaxhighlight>
For the Chromosome column, integer values becomes strings (but converted to double, so 5 becomes 5.000000) or NA (empty on sheets).
<syntaxhighlight lang='rsplus'>
> head(read_excel("~/Downloads/BRCA.xls", 4)[ , -9], 3)
  UniqueID (Double-click) CloneID UGCluster
1                  HK1A1  21652 Hs.445981
2                  HK1A2  22012 Hs.119177
3                  HK1A4  22293 Hs.501376
                                                    Name Symbol EntrezID
1 Catenin (cadherin-associated protein), alpha 1, 102kDa CTNNA1    1495
2                              ADP-ribosylation factor 3  ARF3      377
3                          Uroporphyrinogen III synthase  UROS    7390
  Chromosome      Cytoband ChimericClusterIDs Filter
1  5.000000        5q31.2              <NA>      1
2  12.000000        12q13              <NA>      1
3      <NA> 10q25.2-q26.3              <NA>      1
</syntaxhighlight>


The hidden worksheets become visible (Not sure what are those first rows mean in the output).
=== Convert from pdf to word ===
<syntaxhighlight lang='rsplus'>
The best rendering of advanced tables is done by converting from pdf to Word. See http://biostat.mc.vanderbilt.edu/wiki/Main/SweaveConvert
> excel_sheets("~/Downloads/BRCA.xls")
 
DEFINEDNAME: 21 00 00 01 0b 00 00 00 02 00 00 00 00 00 00 0d 3b 01 00 00 00 9a 0c 00 00 1a 00
=== rtf ===
DEFINEDNAME: 21 00 00 01 0b 00 00 00 04 00 00 00 00 00 00 0d 3b 03 00 00 00 9b 0c 00 00 0a 00
Use [http://cran.r-project.org/web/packages/rtf/ rtf] package for Rich Text Format (RTF) Output.
DEFINEDNAME: 21 00 00 01 0b 00 00 00 03 00 00 00 00 00 00 0d 3b 02 00 00 00 9a 0c 00 00 06 00
[1] "Experiment descriptors" "Filtered log ratio"    "Gene identifiers"     
[4] "Gene annotations"      "CollateInfo"            "GeneSubsets"         
[7] "GeneSubsetsTemp"     
</syntaxhighlight>


The Chinese character works too.
=== [https://www.rdocumentation.org/packages/xtable/versions/1.8-2 xtable] ===
<syntaxhighlight lang='rsplus'>
Package xtable will produce html output.
> read_excel("~/Downloads/testChinese.xlsx", 1)
{{Pre}}
  中文 B C
print(xtable(X), type="html")
1    a b c
</pre>  
2    1 2 3
</syntaxhighlight>


=== [https://cran.r-project.org/web/packages/readr/ readr] ===
If you save the file and then open it with Word, you will get serviceable results. I've had better luck copying the output from xtable and pasting it into Excel.
Compared to base equivalents like '''read.csv()''', '''readr''' is much faster and gives more convenient output: it never converts strings to factors, can parse date/times, and it doesn’t munge the column names.


[https://blog.rstudio.org/2016/08/05/readr-1-0-0/ 1.0.0] released.
=== officer ===
<ul>
<li>[https://cran.r-project.org/web/packages/officer/index.html CRAN]. Microsoft Word, Microsoft Powerpoint and HTML documents generation from R.
<li>The [https://gist.github.com/arraytools/4f182b036ae7f95a31924ba5d5d3f069 gist] includes a comprehensive example that encompasses various elements such as sections, subsections, and tables. It also incorporates a detailed paragraph, along with visual representations created using base R plots and ggplots.  
<li>Add a line space
<pre>
doc <- body_add_par(doc, "")


=== [http://cran.r-project.org/web/packages/ggplot2/index.html ggplot2] ===
# Function to add n line spaces
Free online book (very nice)
body_add_par_n <- function (doc, n) {
* [http://www.cookbook-r.com/Graphs/ R Graphics Cookbook] by Winston Chang.
  for(i in 1:n){
    doc <- body_add_par(doc, "")
  }
  return(doc)
}
body_add_par_n(3)
</pre>
<li>[https://ardata-fr.github.io/officeverse/officer-for-word.html Figures] from the documentation of '''officeverse'''.
<li>See [https://stackoverflow.com/a/25427314 Data frame to word table?].  
<li>See [[Office#Tables|Office]] page for some code.
<li>[https://www.r-bloggers.com/2020/07/how-to-read-and-create-word-documents-in-r/ How to read and create Word Documents in R] where we can extracting tables from Word Documents.
<pre>
x = read_docx("myfile.docx")
content <- docx_summary(x) # a vector
grep("nlme", content$text, ignore.case = T, value = T)
</pre>
</ul>


Some examples:
== Powerpoint ==
* http://blog.diegovalle.net/2015/01/the-74-most-violent-cities-in-mexico.html
<ul>
<li>[https://cran.r-project.org/web/packages/officer/index.html officer] package  (formerly ReporteRs). [http://theautomatic.net/2020/07/28/how-to-create-powerpoint-reports-with-r/ How to create powerpoint reports with R]
</li>
<li>[https://davidgohel.github.io/flextable/ flextable] (imports '''officer''')
</li>
<li>[https://stackoverflow.com/a/21558466 R data.frame to table image for presentation].
<pre>
library(gridExtra)
grid.newpage()
grid.table(mydf)
</pre>
</li>
<li>[https://bookdown.org/yihui/rmarkdown/powerpoint-presentation.html Rmarkdown]
</li>
</ul>


Introduction
== PDF manipulation ==
* https://www.youtube.com/watch?v=SaJCKpYX5Lo&t=2742
[https://github.com/pridiltal/staplr staplr]


==== [https://github.com/cttobin/ggthemr ggthemr]: Themes for ggplot2 ====
== R Graphs Gallery ==
* http://www.shanelynn.ie/themes-and-colours-for-r-ggplots-with-ggthemr/
* [https://www.facebook.com/pages/R-Graph-Gallery/169231589826661 Romain François]
* [http://shinyapps.stat.ubc.ca/r-graph-catalog/ R Graph Catalog] written using R + Shiny. The source code is available on [https://github.com/jennybc/r-graph-catalog Github].
* Forest plot. See the packages [https://cran.r-project.org/web/packages/rmeta/index.html rmeta] and [https://cran.r-project.org/web/packages/forestplot/ forestplot]. The forest plot can be used to plot the quantities like relative risk (with 95% CI) in survival data.
** [http://www.danieldsjoberg.com/bstfun/dev/reference/add_inline_forest_plot.html Inline forest plot]


=== Data Manipulation ===
== COM client or server ==
* [http://datascienceplus.com/best-packages-for-data-manipulation-in-r/ Best packages for data manipulation in R]. It demonstrates to perform the same tasks using '''data.table''' and '''dplyr''' packages. '''data.table''' is faster and it may be a go-to package when performance and memory are the constraints.


==== [http://rpubs.com/danmirman/Rgroup-part1 5 most useful data manipulation functions] ====
=== Client ===
* subset() for making subsets of data (natch)
* [http://www.omegahat.org/RDCOMClient/ RDCOMClient] where [http://cran.r-project.org/web/packages/excel.link/index.html excel.link] depends on it.
* merge() for combining data sets in a smart and easy way
* [https://www.r-bloggers.com/2024/06/how-to-execute-vba-code-in-excel-via-r-using-rdcomclient/ How to Execute VBA Code in Excel via R using RDCOMClient]
* melt()-reshape2 package for converting from wide to long data formats
* dcast()-reshape2 package for converting from long to wide data formats, and for making summary tables
* ddply()-plyr package for doing split-apply-combine operations, which covers a huge swath of the most tricky data operations


==== [https://cran.r-project.org/web/packages/data.table/index.html data.table] ====
=== Server ===
Fast aggregation of large data (e.g. 100GB in RAM or just several GB size file), fast ordered joins, fast add/modify/delete of columns by group using no copies at all, list columns and a fast file reader (fread).
[http://www.omegahat.org/RDCOMServer/ RDCOMServer]


Question: how to make use multicore with data.table package?
== Use R under proxy ==
http://support.rstudio.org/help/kb/faq/configuring-r-to-use-an-http-proxy


* [https://www.r-bloggers.com/importing-data-into-r-part-two/ Reading large data tables in R]
== RStudio ==
<syntaxhighlight lang='rsplus'>
* [https://github.com/rstudio/rstudio Github]
library(data.table)
* Installing RStudio (1.0.44) on Ubuntu will not install Java even the source code contains 37.5% Java??
x <- fread("mylargefile.txt")
* [https://www.rstudio.com/products/rstudio/download/preview/ Preview]
</syntaxhighlight>
 
* Note that '''x[, 2]'' always return 2. If you want to do the thing you want, use ''x[, 2, with=FALSE]'' or ''x[, V2]'' where V2 is the header name. See the FAQ #1 in [http://datatable.r-forge.r-project.org/datatable-faq.pdf data.table].
=== rstudio.cloud ===
* [http://r-norberg.blogspot.com/2016/06/understanding-datatable-rolling-joins.html Understanding data.table Rolling Joins]
https://rstudio.cloud/
* [https://rollingyours.wordpress.com/2016/06/14/fast-aggregation-of-large-data-with-the-data-table-package/ Intro to The data.table Package]
* In the [https://cran.r-project.org/web/packages/data.table/vignettes/datatable-intro-vignette.html Introduction to data.table] vignette, the data.table::order() function is SLOWER than base::order() from my Odroid xu4 (running Ubuntu 14.04.4 trusty on uSD)
<syntaxhighlight lang='rsplus'>
odt = data.table(col=sample(1e7))
(t1 <- system.time(ans1 <- odt[base::order(col)]))  ## uses order from base R
#  user  system elapsed
#  2.730  0.210  2.947
(t2 <- system.time(ans2 <- odt[order(col)]))        ## uses data.table's order
#  user  system elapsed
#  2.830  0.215  3.052
(identical(ans1, ans2))
# [1] TRUE
</syntaxhighlight>
* [https://jangorecki.github.io/blog/2016-06-30/Boost-Your-Data-Munging-with-R.html Boost Your Data Munging with R]


==== stringr, plyr, dplyr packages ====
=== Launch RStudio ===
[[Rstudio#Multiple_versions_of_R|Multiple versions of R]]


http://martinsbioblogg.wordpress.com/2013/03/24/using-r-reading-tables-that-need-a-little-cleaning/
=== Create .Rproj file ===
If you have an existing package that doesn't have an .Rproj file, you can use '''devtools::use_rstudio("path/to/package")''' to add it.


A data.frame is pretty much a list of vectors, so we use plyr to apply over the list and stringr to search and replace in the vectors.
With an RStudio project file, you can
* Restore .RData into workspace at startup
* Save workspace to .RData on exit (or '''save.image'''("Robj.RData") & load("Robj.RData"))
* Always save history (even if no saving .RData, '''savehistory'''(".Rhistory") & loadhistory(".Rhistory"))
* etc


[https://rollingyours.wordpress.com/2016/06/29/express-intro-to-dplyr/ Intro to dplyr] by rollingyours.
=== package search ===
https://github.com/RhoInc/CRANsearcher


==== reshape ====
=== Git ===
[http://r-exercises.com/2016/07/06/data-shape-transformation-with-reshape/ Data Shape Transformation With Reshape()]
* (Video) [https://www.rstudio.com/resources/videos/happy-git-and-gihub-for-the-user-tutorial/ Happy Git and Gihub for the useR – Tutorial]
* [https://owi.usgs.gov/blog/beyond-basic-git/ Beyond Basic R - Version Control with Git]


==== reshape2 ====
== Visual Studio ==
Use '''acast()''' function in reshape2 package. It will convert data.frame used for analysis to a table-like data.frame good for display.
[http://blog.revolutionanalytics.com/2017/05/r-and-python-support-now-built-in-to-visual-studio-2017.html R and Python support now built in to Visual Studio 2017]
* http://lamages.blogspot.com/2013/10/creating-matrix-from-long-dataframe.html


==== [http://cran.r-project.org/web/packages/tidyr/index.html tidyr] ====
== List files using regular expression ==
An evolution of reshape2. It's designed specifically for data tidying (not general reshaping or aggregating) and works well with dplyr data pipelines.
* Extension
<pre>
list.files(pattern = "\\.txt$")
</pre>
where the dot (.) is a metacharacter. It is used to refer to any character.
* Start with
<pre>
list.files(pattern = "^Something")
</pre>


* http://blog.rstudio.org/2014/07/22/introducing-tidyr/
Using '''Sys.glob()"' as
* http://rpubs.com/seandavi/GEOMetadbSurvey2014
<pre>
* http://timelyportfolio.github.io/rCharts_factor_analytics/factors_with_new_R.html
> Sys.glob("~/Downloads/*.txt")
* [http://www.milanor.net/blog/reshape-data-r-tidyr-vs-reshape2/ tidyr vs reshape2]
[1] "/home/brb/Downloads/ip.txt"      "/home/brb/Downloads/valgrind.txt"
* Google: R tidyr
</pre>


==== [https://github.com/smbache/magrittr magrittr] ====
== Hidden tool: rsync in Rtools ==
Instead of nested statements, it is using pipe operator '''%>%'''. So the code is easier to read. Impressive!
<pre>
c:\Rtools\bin>rsync -avz "/cygdrive/c/users/limingc/Downloads/a.exe" "/cygdrive/c/users/limingc/Documents/"
sending incremental file list
a.exe


* http://rud.is/b/2015/02/04/a-step-to-the-right-in-r-assignments/
sent 323142 bytes  received 31 bytes  646346.00 bytes/sec
* http://rpubs.com/tjmahr/pipelines_2015
total size is 1198416  speedup is 3.71
* http://danielmarcelino.com/i-loved-this-crosstable/


==== outer() ====
c:\Rtools\bin>
</pre>


=== [http://cran.r-project.org/web/packages/jpeg/index.html jpeg] ===
Unforunately, if the destination is a network drive, I could get a permission denied (13) error. See also [https://superuser.com/a/69764 rsync file permissions on windows].
If we want to create the image on this wiki left hand side panel, we can use the '''jpeg''' package to read an existing plot and then edit and save it.


We can also use the jpeg package to import and manipulate a jpg image. See [http://moderndata.plot.ly/fun-with-heatmaps-and-plotly/ Fun with Heatmaps and Plotly].
== Install rgdal package (geospatial Data) on ubuntu ==
Terminal
{{Pre}}
sudo apt-get install libgdal1-dev libproj-dev # https://stackoverflow.com/a/44389304
sudo apt-get install libgdal1i # Ubuntu 16.04 https://stackoverflow.com/a/12143411
</pre>


=== cairoDevice ===
R
PS. Not sure the advantage of functions in this package compared to R's functions (eg. Cairo_svg() vs svg()) or even [http://cran.r-project.org/web/packages/Cairo/index.html Cairo] package.
{{Pre}}
install.packages("rgdal")
</pre>


For ubuntu OS, we need to install 2 libraries and 1 R package '''RGtk2'''.
== Install sf package ==
I got the following error even I have installed some libraries.  
<pre>
<pre>
sudo apt-get install libgtk2.0-dev libcairo2-dev
checking GDAL version >= 2.0.1... no
configure: error: sf is not compatible with GDAL versions below 2.0.1
</pre>
</pre>
Then I follow the instruction here
{{Pre}}
sudo apt remove libgdal-dev
sudo apt remove libproj-dev
sudo apt remove gdal-bin
sudo add-apt-repository ppa:ubuntugis/ubuntugis-stable


On Windows OS, we may got the error: '''unable to load shared object 'C:/Program Files/R/R-3.0.2/library/cairoDevice/libs/x64/cairoDevice.dll' '''. We need to follow the instruction in [http://tolstoy.newcastle.edu.au/R/e6/help/09/05/15613.html here].
sudo apt update
sudo apt-cache policy libgdal-dev # Make sure a version >= 2.0 appears


=== [http://cran.r-project.org/web/packages/iterators/ iterators] ===
sudo apt install libgdal-dev # works on ubuntu 20.04 too
Iterator is useful over for-loop if the data is already a '''collection'''. It can be used to iterate over a vector, data frame, matrix, file
                            # no need the previous lines
</pre>
 
== Database ==
* https://cran.r-project.org/web/views/Databases.html
* [http://blog.revolutionanalytics.com/2017/08/a-modern-database-interface-for-r.html A modern database interface for R]
 
=== [http://cran.r-project.org/web/packages/RSQLite/index.html RSQLite] ===
* https://cran.r-project.org/web/packages/RSQLite/vignettes/RSQLite.html
* https://github.com/rstats-db/RSQLite
 
'''Creating a new database''':
{{Pre}}
library(DBI)
 
mydb <- dbConnect(RSQLite::SQLite(), "my-db.sqlite")
dbDisconnect(mydb)
unlink("my-db.sqlite")
 
# temporary database
mydb <- dbConnect(RSQLite::SQLite(), "")
dbDisconnect(mydb)
</pre>
 
'''Loading data''':
{{Pre}}
mydb <- dbConnect(RSQLite::SQLite(), "")
dbWriteTable(mydb, "mtcars", mtcars)
dbWriteTable(mydb, "iris", iris)


Iterator can be combined to use with foreach package http://www.exegetic.biz/blog/2013/11/iterators-in-r/ has more elaboration.
dbListTables(mydb)


=== Colors ===
dbListFields(con, "mtcars")
* http://www.bauer.uh.edu/parks/truecolor.htm Interactive RGB, Alpha and Color Picker
* http://deanattali.com/blog/colourpicker-package/ Not sure what it is doing


==== [http://rpubs.com/gaston/colortools colortools] ====
dbReadTable(con, "mtcars")
Tools that allow users generate color schemes and palettes
</pre>


=== [https://github.com/kevinushey/rex rex] ===
'''Queries''':
Friendly Regular Expressions
{{Pre}}
dbGetQuery(mydb, 'SELECT * FROM mtcars LIMIT 5')


=== [http://cran.r-project.org/web/packages/formatR/index.html formatR] ===
dbGetQuery(mydb, 'SELECT * FROM iris WHERE "Sepal.Length" < 4.6')
'''The best strategy to avoid failure is to put comments in complete lines or after complete R expressions.'''


See also [http://stackoverflow.com/questions/3017877/tool-to-auto-format-r-code this discussion] on stackoverflow talks about R code reformatting.
dbGetQuery(mydb, 'SELECT * FROM iris WHERE "Sepal.Length" < :x', params = list(x = 4.6))


<pre>
res <- dbSendQuery(con, "SELECT * FROM mtcars WHERE cyl = 4")
library(formatR)
dbFetch(res)
tidy_source("Input.R", file = "output.R", width.cutoff=70)
tidy_source("clipboard")  
# default width is getOption("width") which is 127 in my case.
</pre>
</pre>


Some issues
'''Batched queries''':
* Comments appearing at the beginning of a line within a long complete statement. This will break tidy_source().
{{Pre}}
<pre>
dbClearResult(rs)
cat("abcd",
rs <- dbSendQuery(mydb, 'SELECT * FROM mtcars')
    # This is my comment
while (!dbHasCompleted(rs)) {
    "defg")
  df <- dbFetch(rs, n = 10)
  print(nrow(df))
}
 
dbClearResult(rs)
</pre>
</pre>
will result in
 
<pre>
'''Multiple parameterised queries''':
> tidy_source("clipboard")
{{Pre}}
Error in base::parse(text = code, srcfile = NULL) :
rs <- dbSendQuery(mydb, 'SELECT * FROM iris WHERE "Sepal.Length" = :x')
  3:1: unexpected string constant
dbBind(rs, param = list(x = seq(4, 4.4, by = 0.1)))
2: invisible(".BeGiN_TiDy_IdEnTiFiEr_HaHaHa# This is my comment.HaHaHa_EnD_TiDy_IdEnTiFiEr")
nrow(dbFetch(rs))
3: "defg"
#> [1] 4
  ^
dbClearResult(rs)
</pre>
 
'''Statements''':
{{Pre}}
dbExecute(mydb, 'DELETE FROM iris WHERE "Sepal.Length" < 4')
#> [1] 0
rs <- dbSendStatement(mydb, 'DELETE FROM iris WHERE "Sepal.Length" < :x')
dbBind(rs, param = list(x = 4.5))
dbGetRowsAffected(rs)
#> [1] 4
dbClearResult(rs)
</pre>
</pre>
* Comments appearing at the end of a line within a long complete statement ''won't break'' tidy_source() but tidy_source() cannot re-locate/tidy the comma sign.  
 
<pre>
=== [https://cran.r-project.org/web/packages/sqldf/ sqldf] ===
cat("abcd"
Manipulate R data frames using SQL. Depends on RSQLite. [http://datascienceplus.com/a-use-of-gsub-reshape2-and-sqldf-with-healthcare-data/ A use of gsub, reshape2 and sqldf with healthcare data]
    ,"defg"   # This is my comment
 
  ,"ghij")
=== [https://cran.r-project.org/web/packages/RPostgreSQL/index.html RPostgreSQL] ===
 
=== [[MySQL#Use_through_R|RMySQL]] ===
* http://datascienceplus.com/bringing-the-powers-of-sql-into-r/
* See [[MySQL#Installation|here]] about the installation of the required package ('''libmysqlclient-dev''') in Ubuntu.
 
=== MongoDB ===
* http://www.r-bloggers.com/r-and-mongodb/
* http://watson.nci.nih.gov/~sdavis/blog/rmongodb-using-R-with-mongo/
 
=== odbc ===
 
=== RODBC ===
 
=== DBI ===
 
=== [https://cran.r-project.org/web/packages/dbplyr/index.html dbplyr] ===
* To use databases with dplyr, you need to first install dbplyr
* https://db.rstudio.com/dplyr/
* Five commonly used backends: RMySQL, RPostgreSQ, RSQLite, ODBC, bigrquery.
* http://www.datacarpentry.org/R-ecology-lesson/05-r-and-databases.html
 
'''Create a new SQLite database''':
{{Pre}}
surveys <- read.csv("data/surveys.csv")
plots <- read.csv("data/plots.csv")
 
my_db_file <- "portal-database.sqlite"
my_db <- src_sqlite(my_db_file, create = TRUE)
 
copy_to(my_db, surveys)
copy_to(my_db, plots)
my_db
</pre>
</pre>
will become
 
<pre>
'''Connect to a database''':
cat("abcd", "defg" # This is my comment
{{Pre}}
, "ghij")  
download.file(url = "https://ndownloader.figshare.com/files/2292171",
              destfile = "portal_mammals.sqlite", mode = "wb")
 
library(dbplyr)
library(dplyr)
mammals <- src_sqlite("portal_mammals.sqlite")
</pre>
</pre>
Still bad!!
 
* Comments appearing at the end of a line within a long complete statement ''breaks'' tidy_source() function. For example,
'''Querying the database with the SQL syntax''':
<pre>
{{Pre}}
cat("</p>",
tbl(mammals, sql("SELECT year, species_id, plot_id FROM surveys"))
"<HR SIZE=5 WIDTH=\"100%\" NOSHADE>",
ifelse(codeSurv == 0,"<h3><a name='Genes'><b><u>Genes which are differentially expressed among classes:</u></b></a></h3>", #4/9/09
                    "<h3><a name='Genes'><b><u>Genes significantly associated with survival:</u></b></a></h3>"),
file=ExternalFileName, sep="\n", append=T)
</pre>
</pre>
will result in
 
<pre>
'''Querying the database with the dplyr syntax''':
> tidy_source("clipboard", width.cutoff=70)
{{Pre}}
Error in base::parse(text = code, srcfile = NULL) :
surveys <- tbl(mammals, "surveys")
  3:129: unexpected SPECIAL
surveys %>%
2: "<HR SIZE=5 WIDTH=\"100%\" NOSHADE>" ,
    select(year, species_id, plot_id)
3: ifelse ( codeSurv == 0 , "<h3><a name='Genes'><b><u>Genes which are differentially expressed among classes:</u></b></a></h3>" , %InLiNe_IdEnTiFiEr%
head(surveys, n = 10)
 
show_query(head(surveys, n = 10)) # show which SQL commands are actually sent to the database
</pre>
</pre>
* ''width.cutoff'' parameter is not always working. For example, there is no any change for the following snippet though I hope it will move the cat() to the next line.
 
<pre>
'''Simple database queries''':
if (codePF & !GlobalTest & !DoExactPermTest) cat(paste("Multivariate Permutations test was computed based on",
{{Pre}}
    NumPermutations, "random permutations"), "<BR>", " ", file = ExternalFileName,
surveys %>%
    sep = "\n", append = T)
  filter(weight < 5) %>%
  select(species_id, sex, weight)
</pre>
</pre>
* It merges lines though I don't always want to do that. For example
 
<pre>
'''Laziness''' (instruct R to stop being lazy):
cat("abcd"
{{Pre}}
    ,"defg" 
data_subset <- surveys %>%
   ,"ghij")
  filter(weight < 5) %>%
  select(species_id, sex, weight) %>%
   collect()
</pre>
</pre>
will become
 
<pre>
'''Complex database queries''':
cat("abcd", "defg", "ghij")  
{{Pre}}
plots <- tbl(mammals, "plots")
plots # # The plot_id column features in the plots table
 
surveys # The plot_id column also features in the surveys table
 
# Join databases method 1
plots %>%
  filter(plot_id == 1) %>%
  inner_join(surveys) %>%
  collect()
</pre>
</pre>


=== Download papers ===
=== NoSQL ===
==== [http://cran.r-project.org/web/packages/biorxivr/index.html biorxivr] ====
[https://ropensci.org/technotes/2018/01/25/nodbi/ nodbi: the NoSQL Database Connector]
Search and Download Papers from the bioRxiv Preprint Server


==== [http://cran.r-project.org/web/packages/aRxiv/index.html aRxiv] ====
== Github ==
Interface to the arXiv API


==== [https://cran.r-project.org/web/packages/pdftools/index.html pdftools] ====
=== R source  ===
http://ropensci.org/blog/2016/03/01/pdftools-and-jeroen
https://github.com/wch/r-source/ Daily update, interesting, should be visited every day. Clicking '''1000+ commits''' to look at daily changes.


== Different ways of using R ==
If we are interested in a certain branch (say 3.2), look for R-3-2-branch.


=== R call C/C++ ===
=== R packages (only) source (metacran) ===
Mainly talks about .C() and .Call().
* https://github.com/cran/ by [https://github.com/gaborcsardi Gábor Csárdi], the author of '''[http://igraph.org/ igraph]''' software.


* [http://cran.r-project.org/doc/manuals/R-exts.html R-Extension manual] of course.
=== Bioconductor packages source ===
* http://faculty.washington.edu/kenrice/sisg-adv/sisg-07.pdf
<strike>[https://stat.ethz.ch/pipermail/bioc-devel/2015-June/007675.html Announcement], https://github.com/Bioconductor-mirror </strike>
* http://www.stat.berkeley.edu/scf/paciorek-cppWorkshop.pdf (Very useful)
* http://www.stat.harvard.edu/ccr2005/
* http://mazamascience.com/WorkingWithData/?p=1099


=== R call Fortran 90 ===
=== Send local repository to Github in R by using reports package ===
* https://stat.ethz.ch/pipermail/r-devel/2015-March/070851.html
http://www.youtube.com/watch?v=WdOI_-aZV0Y


=== Embedding R ===
=== My collection ===
* https://github.com/arraytools
* https://gist.github.com/4383351 heatmap using leukemia data
* https://gist.github.com/4382774 heatmap using sequential data
* https://gist.github.com/4484270 biocLite


* See [http://cran.r-project.org/doc/manuals/R-exts.html#Linking-GUIs-and-other-front_002dends-to-R Writing for R Extensions] Manual Chapter 8.
=== How to download ===
* [http://www.ci.tuwien.ac.at/Conferences/useR-2004/abstracts/supplements/Urbanek.pdf Talk by Simon Urbanek] in UseR 2004.
* [http://epub.ub.uni-muenchen.de/2085/1/tr012.pdf Technical report]  by Friedrich Leisch in 2007.
* https://stat.ethz.ch/pipermail/r-help/attachments/20110729/b7d86ed7/attachment.pl


==== An very simple example (do not return from shell) from Writing R Extensions manual ====
Clone ~ Download.  
The command-line R front-end, R_HOME/bin/exec/R, is one such example. Its source code is in file <src/main/Rmain.c>.
* Command line
 
This example can be run by
<pre>R_HOME/bin/R CMD R_HOME/bin/exec/R</pre>
 
Note:
# '''R_HOME/bin/exec/R''' is the R binary. However, it couldn't be launched directly unless R_HOME and LD_LIBRARY_PATH are set up. Again, this is explained in Writing R Extension manual.
# '''R_HOME/bin/R''' is a shell-script front-end where users can invoke it. It sets up the environment for the executable. It can be copied to ''/usr/local/bin/R''. When we run ''R_HOME/bin/R'', it actually runs ''R_HOME/bin/R CMD R_HOME/bin/exec/R'' (see line 259 of ''R_HOME/bin/R'' as in R 3.0.2) so we know the important role of ''R_HOME/bin/exec/R''.
 
More examples of embedding can be found in ''tests/Embedding'' directory. Read <index.html> for more information about these test examples.
 
==== An example from Bioconductor workshop ====
* What is covered in this section is different from [[R#Create_a_standalone_Rmath_library|Create and use a standalone Rmath library]].
* Use eval() function. See R-Ext [http://cran.r-project.org/doc/manuals/R-exts.html#Embedding-R-under-Unix_002dalikes 8.1] and [http://cran.r-project.org/doc/manuals/R-exts.html#Embedding-R-under-Windows 8.2] and [http://cran.r-project.org/doc/manuals/R-exts.html#Evaluating-R-expressions-from-C 5.11].
* http://stackoverflow.com/questions/2463437/r-from-c-simplest-possible-helloworld (obtained from searching R_tryEval on google)
* http://stackoverflow.com/questions/7457635/calling-r-function-from-c
 
Example:
Create <embed.c> file
<pre>
<pre>
#include <Rembedded.h>
git clone https://gist.github.com/4484270.git
#include <Rdefines.h>
</pre>
This will create a subdirectory called '4484270' with all cloned files there.


static void doSplinesExample();
* Within R
int
<pre>
main(int argc, char *argv[])
library(devtools)
{
source_gist("4484270")
    Rf_initEmbeddedR(argc, argv);
</pre>
    doSplinesExample();
or
    Rf_endEmbeddedR(0);
First download the json file from
    return 0;
https://api.github.com/users/MYUSERLOGIN/gists
}
and then
static void
<pre>
doSplinesExample()
library(RJSONIO)
{
x <- fromJSON("~/Downloads/gists.json")
    SEXP e, result;
setwd("~/Downloads/")
    int errorOccurred;
gist.id <- lapply(x, "[[", "id")
lapply(gist.id, function(x){
  cmd <- paste0("git clone https://gist.github.com/", x, ".git")
  system(cmd)
})
</pre>
 
=== Jekyll ===
[http://statistics.rainandrhino.org/2015/12/15/jekyll-r-blogger-knitr-hyde.html An Easy Start with Jekyll, for R-Bloggers]
 
== Connect R with Arduino ==
* https://zhuhao.org/post/connect-arduino-chips-with-r/
* http://lamages.blogspot.com/2012/10/connecting-real-world-to-r-with-arduino.html
* http://jean-robert.github.io/2012/11/11/thermometer-R-using-Arduino-Java.html
* http://bio7.org/?p=2049
* http://www.rforge.net/Arduino/svn.html


    // create and evaluate 'library(splines)'
== Android App ==
    PROTECT(e = lang2(install("library"), mkString("splines")));
* [https://play.google.com/store/apps/details?id=appinventor.ai_RInstructor.R2&hl=zh_TW R Instructor] $4.84
    R_tryEval(e, R_GlobalEnv, &errorOccurred);
* [http://realxyapp.blogspot.tw/2010/12/statistical-distribution.html Statistical Distribution] (Not R related app)
    if (errorOccurred) {
* [https://datascienceplus.com/data-driven-introspection-of-my-android-mobile-usage-in-r/ Data-driven Introspection of my Android Mobile usage in R]
        // handle error
    }
    UNPROTECT(1);


    // 'options(FALSE)' ...
== Common plots tips ==
    PROTECT(e = lang2(install("options"), ScalarLogical(0)));
=== Create an empty plot ===
    // ... modified to 'options(example.ask=FALSE)' (this is obscure)
'''plot.new()'''   
    SET_TAG(CDR(e), install("example.ask"));
    R_tryEval(e, R_GlobalEnv, NULL);
    UNPROTECT(1);


    // 'example("ns")'
=== Overlay plots ===
    PROTECT(e = lang2(install("example"), mkString("ns")));
[https://finnstats.com/index.php/2021/08/15/how-to-overlay-plots-in-r/ How to Overlay Plots in R-Quick Guide with Example].
    R_tryEval(e, R_GlobalEnv, &errorOccurred);
<pre>
    UNPROTECT(1);
#Step1:-create scatterplot
}
plot(x1, y1)
#Step 2:-overlay line plot
lines(x2, y2)
#Step3:-overlay scatterplot
points(x2, y2)
</pre>
</pre>
Then build the executable. Note that I don't need to create R_HOME variable.
 
=== Save the par() and restore it ===
'''Example 1''': Don't use old.par <- par() directly. no.readonly = FALSE by default. * The '''`no.readonly = TRUE`''' argument in the [https://www.rdocumentation.org/packages/graphics/versions/3.6.2/topics/par par()] function in R is used to get the full list of graphical parameters '''that can be restored'''.
* When you call `par()` with no arguments or `par(no.readonly = TRUE)`, it returns an invisible named list of all the graphical parameters. This includes both parameters that can be set and those that are read-only.
* If we use par(old.par) where old.par <- par(), we will get several warning messages like 'In par(op) : graphical parameter "cin" cannot be set'.
<pre>
<pre>
cd
old.par <- par(no.readonly = TRUE); par(mar = c(5, 4, 4, 2) - 2)  # OR in one step
tar xzvf
old.par <- par(mar = c(5, 4, 4, 2) - 2)
cd R-3.0.1
## do plotting stuff with new settings
./configure --enable-R-shlib
par(old.par)
make
</pre>
cd tests/Embedding
'''Example 2''': Use it inside a function with the [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/on.exit on.exit(0] function.
make
<pre>
~/R-3.0.1/bin/R CMD ./Rtest
ex <- function() {
 
  old.par <- par(no.readonly = TRUE) # all par settings which
nano embed.c
                                      # could be changed.
# Using a single line will give an error and cannot not show the real problem.
  on.exit(par(old.par))
# ../../bin/R CMD gcc -I../../include -L../../lib -lR embed.c
  ## ... do lots of par() settings and plots
# A better way is to run compile and link separately
  ## ...
gcc -I../../include -c embed.c
  invisible() #-- now,  par(old.par)  will be executed
gcc -o embed embed.o -L../../lib -lR -lRblas
}
../../bin/R CMD ./embed
</pre>
'''Example 3''': It seems par() inside a function will affect the global environment. But if we use dev.off(), it will reset all parameters.
<pre>
ex <- function() { par(mar=c(5,4,4,1)) }
ex()
par()$mar
</pre>
</pre>
Note that if we want to call the executable file ./embed directly, we shall set up R environment by specifying '''R_HOME''' variable and including the directories used in linking R in '''LD_LIBRARY_PATH'''. This is based on the inform provided by [http://cran.r-project.org/doc/manuals/r-devel/R-exts.html Writing R Extensions].
<pre>
<pre>
export R_HOME=/home/brb/Downloads/R-3.0.2
ex = function() { png("~/Downloads/test.png"); par(mar=c(5,4,4,1)); dev.off()}
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/brb/Downloads/R-3.0.2/lib
ex()
./embed # No need to include R CMD in front.
par()$mar
</pre>
</pre>


Question: Create a data frame in C? Answer: [https://stat.ethz.ch/pipermail/r-devel/2013-August/067107.html Use data.frame() via an eval() call from C]. Or see the code is stats/src/model.c, as part of model.frame.default. Or using Rcpp as [https://stat.ethz.ch/pipermail/r-devel/2013-August/067109.html here].
=== Grouped boxplots ===
* [http://r-video-tutorial.blogspot.com/2013/06/box-plot-with-r-tutorial.html Step by step to create a grouped boxplots]
** 'at' parameter in boxplot() to change the equal spaced boxplots
** embed par(mar=) in boxplot()
** mtext(line=) to solve the problem the xlab overlapped with labels.
* [https://stackoverflow.com/questions/28426026/plotting-boxplots-of-multiple-y-variables-using-ggplot2-qplot-or-others ggplot2 approach] (Hint: '''facet_grid''' is used)
 
=== [https://www.samruston.co.uk/ Weather Time Line] ===
The plot looks similar to a boxplot though it is not. See a [https://www.samruston.co.uk/images/screens/screen_2.png screenshot] on Android by [https://www.samruston.co.uk/ Sam Ruston].
 
=== Horizontal bar plot ===
{{Pre}}
library(ggplot2)
dtf <- data.frame(x = c("ETB", "PMA", "PER", "KON", "TRA",
                        "DDR", "BUM", "MAT", "HED", "EXP"),
                  y = c(.02, .11, -.01, -.03, -.03, .02, .1, -.01, -.02, 0.06))
ggplot(dtf, aes(x, y)) +
  geom_bar(stat = "identity", aes(fill = x), show.legend = FALSE) +
  coord_flip() + xlab("") + ylab("Fold Change") 
</pre>


Reference http://bioconductor.org/help/course-materials/2012/Seattle-Oct-2012/AdvancedR.pdf
[[:File:Ggplot2bar.svg]]


==== Create a Simple Socket Server in R ====
=== Include bar values in a barplot ===
This example is coming from this [http://epub.ub.uni-muenchen.de/2085/1/tr012.pdf paper].
* https://stats.stackexchange.com/questions/3879/how-to-put-values-over-bars-in-barplot-in-r.
* [http://stackoverflow.com/questions/12481430/how-to-display-the-frequency-at-the-top-of-each-factor-in-a-barplot-in-r barplot(), text() and axis()] functions. The data can be from a table() object.
* [https://stackoverflow.com/questions/11938293/how-to-label-a-barplot-bar-with-positive-and-negative-bars-with-ggplot2 How to label a barplot bar with positive and negative bars with ggplot2]


Create an R function
Use text().  
<pre>
 
simpleServer <- function(port=6543)
Or use geom_text() if we are using the ggplot2 package. See an example [http://dsgeek.com/2014/09/19/Customizingggplot2charts.html here] or [https://rpubs.com/escott8908/RGC_Ch3_Gar_Graphs this].
{
  sock <- socketConnection ( port=port , server=TRUE)
  on.exit(close( sock ))
  cat("\nWelcome to R!\nR>" ,file=sock )
  while(( line <- readLines ( sock , n=1)) != "quit")
  {
    cat(paste("socket >" , line , "\n"))
    out<- capture.output (try(eval(parse(text=line ))))
    writeLines ( out , con=sock )
    cat("\nR> " ,file =sock )
  }
}
</pre>
Then run simpleServer(). Open another terminal and try to communicate with the server
<pre>
$ telnet localhost 6543
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.


Welcome to R!
For stacked barplot, see [http://t-redactyl.io/blog/2016/01/creating-plots-in-r-using-ggplot2-part-4-stacked-bar-plots.html this] post.
R> summary(iris[, 3:5])
  Petal.Length    Petal.Width          Species 
Min.  :1.000  Min.  :0.100  setosa    :50 
1st Qu.:1.600  1st Qu.:0.300  versicolor:50 
Median :4.350  Median :1.300  virginica :50 
Mean  :3.758  Mean  :1.199                 
3rd Qu.:5.100  3rd Qu.:1.800                 
Max.  :6.900  Max.  :2.500                 


R> quit
=== Grouped barplots ===
Connection closed by foreign host.
* https://www.r-graph-gallery.com/barplot/, https://www.r-graph-gallery.com/48-grouped-barplot-with-ggplot2/ (simpliest, no error bars)
{{Pre}}
library(ggplot2)
# mydata <- data.frame(OUTGRP, INGRP, value)
ggplot(mydata, aes(fill=INGRP, y=value, x=OUTGRP)) +
      geom_bar(position="dodge", stat="identity")
</pre>
* https://datascienceplus.com/building-barplots-with-error-bars/. The error bars define 2 se (95% interval) for the black-and-white version and 1 se (68% interval) for ggplots. Be careful.
{{Pre}}
> 1 - 2*(1-pnorm(1))
[1] 0.6826895
> 1 - 2*(1-pnorm(1.96))
[1] 0.9500042
</pre>
</pre>
* [http://stackoverflow.com/questions/27466035/adding-values-to-barplot-of-table-in-r two bars in one factor] (stack). The data can be a 2-dim matrix with numerical values.
* [http://stats.stackexchange.com/questions/3879/how-to-put-values-over-bars-in-barplot-in-r two bars in one factor], [https://stats.stackexchange.com/questions/14118/drawing-multiple-barplots-on-a-graph-in-r Drawing multiple barplots on a graph in R] (next to each other)
** [https://datascienceplus.com/building-barplots-with-error-bars/ Include error bars]
* [http://bl.ocks.org/patilv/raw/7360425/ Three variables] barplots
* [https://peltiertech.com/stacked-bar-chart-alternatives/ More alternatives] (not done by R)


==== [http://www.rforge.net/Rserve/doc.html Rserve] ====
=== Unicode symbols ===
Note the way of launching Rserve is like the way we launch C program when R was embedded in C. See [[R#Call_R_from_C.2FC.2B.2B|Call R from C/C++]] or [[R#An_Example_from_Bioconductor_Workshop|Example from Bioconductor workshop]].
[https://www.r-bloggers.com/2024/09/mind-reader-game-and-unicode-symbols/ Mind reader game, and Unicode symbols]


See my [[Rserve]] page.
=== Math expression ===
* [https://www.rdocumentation.org/packages/grDevices/versions/3.5.0/topics/plotmath ?plotmath]
* https://stackoverflow.com/questions/4973898/combining-paste-and-expression-functions-in-plot-labels
* Some cases
** Use [https://www.rdocumentation.org/packages/base/versions/3.6.0/topics/expression expression()] function
** Don't need the backslash; use ''eta'' instead of ''\eta''. ''eta'' will be recognized as a special keyword in expression()
** Use parentheses instead of curly braces; use ''hat(eta)'' instead of ''hat{eta}''
** Summary: use expression(hat(eta)) instead of expression(\hat{\eta})
** [] means subscript, while ^ means superscript. See [https://statisticsglobe.com/add-subscript-and-superscript-to-plot-in-r Add Subscript and Superscript to Plot in R]
** Spacing can be done with ~.
** Mix math symbols and text using paste()
** Using substitute() and paste() if we need to substitute text (this part is advanced)
{{Pre}}
# Expressions
plot(x,y, xlab = expression(hat(x)[t]),
    ylab = expression(phi^{rho + a}),
    main = "Pure Expressions")


==== (Commercial) [http://www.statconn.com/ StatconnDcom] ====
# Superscript
plot(1:10, main = expression("My Title"^2))
# Subscript
plot(1:10, main = expression("My Title"[2])) 


==== [http://rdotnet.codeplex.com/ R.NET] ====
# Expressions with Spacing
# '~' is to add space and '*' is to squish characters together
plot(1:10, xlab= expression(Delta * 'C'))
plot(x,y, xlab = expression(hat(x)[t] ~ z ~ w),
    ylab = expression(phi^{rho + a} * z * w),
    main = "Pure Expressions with Spacing")


==== RJava ====
# Expressions with Text
plot(x,y,
    xlab = expression(paste("Text here ", hat(x), " here ", z^rho, " and here")),
    ylab = expression(paste("Here is some text of ", phi^{rho})),
    main = "Expressions with Text")


==== RCaller ====
# Substituting Expressions
plot(x,y,
    xlab = substitute(paste("Here is ", pi, " = ", p), list(p = py)),
    ylab = substitute(paste("e is = ", e ), list(e = ee)),
    main = "Substituted Expressions")
</pre>
 
=== Impose a line to a scatter plot ===
* abline + lsfit # least squares
{{Pre}}
plot(cars)
abline(lsfit(cars[, 1], cars[, 2]))
# OR
abline(lm(cars[,2] ~ cars[,1]))
</pre>
* abline + line # robust line fitting
{{Pre}}
plot(cars)
(z <- line(cars))
abline(coef(z), col = 'green')
</pre>
* lines
{{Pre}}
plot(cars)
fit <- lm(cars[,2] ~ cars[,1])
lines(cars[,1], fitted(fit), col="blue")
lines(stats::lowess(cars), col='red')
</pre>


==== RApache ====
=== How to actually make a quality scatterplot in R: axis(), mtext() ===
* http://www.stat.ucla.edu/~jeroen/files/seminar.pdf
[https://www.r-bloggers.com/2021/08/how-to-actually-make-a-quality-scatterplot-in-r/ How to actually make a quality scatterplot in R]


==== littler ====
=== 3D scatterplot ===
http://dirk.eddelbuettel.com/code/littler.html
* [http://sthda.com/english/wiki/scatterplot3d-3d-graphics-r-software-and-data-visualization Scatterplot3d: 3D graphics - R software and data visualization]. [https://stackoverflow.com/a/24510286 how to add legend to scatterplot3d in R] and consider '''xpd=TRUE'''.
* [[R_web#plotly|R web > plotly]]


[http://stackoverflow.com/questions/3205302/difference-between-rscript-and-littler Difference between Rscript and littler]
=== Rotating x axis labels for barplot ===
https://stackoverflow.com/questions/10286473/rotating-x-axis-labels-in-r-for-barplot
{{Pre}}
barplot(mytable,main="Car makes",ylab="Freqency",xlab="make",las=2)
</pre>


==== RInside: Embed R in C++ ====
=== Set R plots x axis to show at y=0 ===
See [[R#RInside|RInside]]
https://stackoverflow.com/questions/3422203/set-r-plots-x-axis-to-show-at-y-0
{{Pre}}
plot(1:10, rnorm(10), ylim=c(0,10), yaxs="i")
</pre>
 
=== Different colors of axis labels in barplot ===
See [https://stackoverflow.com/questions/18839731/vary-colors-of-axis-labels-in-r-based-on-another-variable Vary colors of axis labels in R based on another variable]


(''From RInside documentation'') The RInside package makes it easier to embed R in your C++ applications. There is no code you would execute directly from the R environment. Rather, you write C++ programs that embed R which is illustrated by some the included examples.
Method 1: Append labels for the 2nd, 3rd, ... color gradually because 'col.axis' argument cannot accept more than one color.
{{Pre}}
tN <- table(Ni <- stats::rpois(100, lambda = 5))
r <- barplot(tN, col = rainbow(20))
axis(1, 1, LETTERS[1], col.axis="red", col="red")
axis(1, 2, LETTERS[2], col.axis="blue", col = "blue")
</pre>


The included examples are armadillo, eigen, mpi, qt, standard, threads and wt.
Method 2: text() which can accept multiple colors in 'col' parameter but we need to find out the (x, y) by ourselves.
{{Pre}}
barplot(tN, col = rainbow(20), axisnames = F)
text(4:6, par("usr")[3]-2 , LETTERS[4:6], col=c("black","red","blue"), xpd=TRUE)
</pre>


To run 'make' when we don't have a global R, we should modify the file <Makefile>. Also if we just want to create one executable file, we can do, for example, 'make rinside_sample1'.
=== Use text() to draw labels on X/Y-axis including rotation ===
* adj = 1 means top/right alignment.  For left-bottom alignment, set adj = 0. The default is to center the text. [[https://www.rdocumentation.org/packages/graphics/versions/3.4.3/topics/text ?text]
* [https://www.rdocumentation.org/packages/graphics/versions/3.4.3/topics/par par("usr")] gives the extremes of the user coordinates of the plotting region of the form c(x1, x2, y1, y2).
** par("usr") is determined *after* a plot has been created
** [http://sphaerula.com/legacy/R/placingTextInPlots.html Example of using the "usr" parameter]
* https://datascienceplus.com/building-barplots-with-error-bars/
{{Pre}}
par(mar = c(5, 6, 4, 5) + 0.1)
plot(..., xaxt = "n") # "n" suppresses plotting of the axis; need mtext() and axis() to supplement
text(x = barCenters, y = par("usr")[3] - 1, srt = 45,
    adj = 1, labels = myData$names, xpd = TRUE)
</pre>
* https://www.r-bloggers.com/rotated-axis-labels-in-r-plots/


To run any executable program, we need to specify '''LD_LIBRARY_PATH''' variable, something like
=== Vertically stacked plots with the same x axis ===
<pre>export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/brb/Downloads/R-3.0.2/lib </pre>
https://stackoverflow.com/questions/11794436/stacking-multiple-plots-vertically-with-the-same-x-axis-but-different-y-axes-in


The real build process looks like (check <Makefile> for completeness)
=== Include labels on the top axis/margin: axis() and mtext() ===
<pre>
<pre>
g++ -I/home/brb/Downloads/R-3.0.2/include \
plot(1:4, rnorm(4), axes = FALSE)
    -I/home/brb/Downloads/R-3.0.2/library/Rcpp/include \
axis(3, at=1:4, labels = LETTERS[1:4], tick = FALSE, line = -0.5) # las, cex.axis
    -I/home/brb/Downloads/R-3.0.2/library/RInside/include -g -O2 -Wall \
box()
    -I/usr/local/include  \
mtext("Groups selected", cex = 0.8, line = 1.5) # default side = 3
    rinside_sample0.cpp  \
    -L/home/brb/Downloads/R-3.0.2/lib -lR  -lRblas -lRlapack \
    -L/home/brb/Downloads/R-3.0.2/library/Rcpp/lib -lRcpp \
    -Wl,-rpath,/home/brb/Downloads/R-3.0.2/library/Rcpp/lib \
    -L/home/brb/Downloads/R-3.0.2/library/RInside/lib -lRInside \
    -Wl,-rpath,/home/brb/Downloads/R-3.0.2/library/RInside/lib \
    -o rinside_sample0
</pre>
</pre>
See also [[#15_Questions_All_R_Users_Have_About_Plots| 15_Questions_All_R_Users_Have_About_Plots]]


Hello World example of embedding R in C++.
This can be used to annotate each plot with the script name, date, ...
<pre>
<pre>
#include <RInside.h>                   // for the embedded R via RInside
mtext(text=paste("Prepared on", format(Sys.time(), "%d %B %Y at %H:%M")),
      adj=.99,  # text align to right
      cex=.75, side=3, las=1, line=2)
</pre>


int main(int argc, char *argv[]) {
ggplot2 uses '''breaks''' instead of '''at''' parameter. See [[Ggplot2#Add_axis_on_top_or_right_hand_side|ggplot2 &rarr; Add axis on top or right hand side]], [[Ggplot2#ggplot2::scale_-_axes.2Faxis.2C_legend|ggplot2 &rarr; scale_x_continus(name, breaks, labels)]] and the [https://ggplot2.tidyverse.org/reference/scale_continuous.html scale_continuous documentation].


    RInside R(argc, argv);              // create an embedded R instance
=== Legend tips ===
[https://r-coder.com/add-legend-r/ Add legend to a plot in R]


    R["txt"] = "Hello, world!\n"; // assign a char* (string) to 'txt'
[https://stackoverflow.com/a/36842578 Increase/decrease legend font size] '''cex''' & [[Ggplot2#Legend_size|ggplot2]] package case.
{{Pre}}
plot(rnorm(100))
# op <- par(cex=2)
legend("topleft", legend = 1:4, col=1:4, pch=1, lwd=2, lty = 1, cex =2)
# par(op)
</pre>


    R.parseEvalQ("cat(txt)");          // eval the init string, ignoring any returns
'''legend inset'''. Default is 0. % (from 0 to 1) to draw the legend away from x and y axis. The inset argument with [https://stackoverflow.com/a/10528078 negative values moves the legend outside the plot].
<pre>
legend("bottomright", inset=.05, )
</pre>


    exit(0);
'''legend without a box'''
}
<pre>
legend(, bty = "n")
</pre>
</pre>


The above can be compared to the Hello world example in Qt.
'''Add a legend title'''
<pre>
<pre>
#include <QApplication.h>
legend(, title = "")
#include <QPushButton.h>
</pre>
 
[https://stackoverflow.com/a/60971923 Add a common legend to multiple plots]. Use the layout function.


int main( int argc, char **argv )
=== Superimpose a density plot or any curves ===
{
Use '''lines()'''.
    QApplication app( argc, argv );


    QPushButton hello( "Hello world!", 0 );
Example 1
    hello.resize( 100, 30 );
{{Pre}}
plot(cars, main = "Stopping Distance versus Speed")
lines(stats::lowess(cars))


    app.setMainWidget( &hello );
plot(density(x), col = "#6F69AC", lwd = 3)
    hello.show();
lines(density(y), col = "#95DAC1", lwd = 3)
lines(density(z), col = "#FFEBA1", lwd = 3)
</pre>


    return app.exec();
Example 2
}
{{Pre}}
require(survival)
n = 10000
beta1 = 2; beta2 = -1
lambdaT = 1 # baseline hazard
lambdaC = 2  # hazard of censoring
set.seed(1234)
x1 = rnorm(n,0)
x2 = rnorm(n,0)
# true event time
T = rweibull(n, shape=1, scale=lambdaT*exp(-beta1*x1-beta2*x2))
C <- rweibull(n, shape=1, scale=lambdaC) 
time = pmin(T,C) 
status <- 1*(T <= C)
status2 <- 1-status
plot(survfit(Surv(time, status2) ~ 1),
    ylab="Survival probability",
    main = 'Exponential censoring time')
xseq <- seq(.1, max(time), length =100)
func <- function(x) 1-pweibull(x, shape = 1, scale = lambdaC)
lines(xseq, func(xseq), col = 'red') # survival function of Weibull
</pre>
</pre>


==== [http://www.rfortran.org/ RFortran] ====
Example 3. Use ggplot(df, aes(x = x, color = factor(grp))) + geom_density(). Then each density curve will represent data from each "grp".
RFortran is an open source project with the following aim:


''To provide an easy to use Fortran software library that enables Fortran programs to transfer data and commands to and from R.''
=== log scale ===
If we set y-axis to use log-scale, then what we display is the value log(Y) or log10(Y) though we still label the values using the input. For example, when we plot c(1, 10, 100) using the log scale, it is like we draw log10(c(1, 10, 100)) = c(0,1,2) on the plot but label the axis using the true values c(1, 10, 100).


It works only on Windows platform with Microsoft Visual Studio installed:(
[[:File:Logscale.png]]


=== Call R from other languages ===
=== Custom scales ===
==== JRI ====
[https://rcrastinate.rbind.io/post/using-custom-scales-with-the-scales-package/ Using custom scales with the 'scales' package]
http://www.rforge.net/JRI/


==== ryp2 ====
== Time series ==
http://rpy.sourceforge.net/rpy2.html
* [https://www.amazon.com/Applied-Time-Analysis-R-Second/dp/1498734227 Applied Time Series Analysis with R]
* [http://www.springer.com/us/book/9780387759586 Time Series Analysis With Applications in R]


=== Create a standalone Rmath library ===
=== Time series stock price plot ===
R has many math and statistical functions. We can easily use these functions in our C/C++/Fortran. The definite guide of doing this is on Chapter 9 "The standalone Rmath library" of [http://cran.r-project.org/doc/manuals/R-admin.html#The-standalone-Rmath-library R-admin manual].
* http://blog.revolutionanalytics.com/2015/08/plotting-time-series-in-r.html (ggplot2, xts, [https://rstudio.github.io/dygraphs/ dygraphs])
* [https://datascienceplus.com/visualize-your-portfolios-performance-and-generate-a-nice-report-with-r/ Visualize your Portfolio’s Performance and Generate a Nice Report with R]
* https://timelyportfolio.github.io/rCharts_time_series/history.html


Here is my experience based on R 3.0.2 on Windows OS.
{{Pre}}
library(quantmod)
getSymbols("AAPL")
getSymbols("IBM") # similar to AAPL
getSymbols("CSCO") # much smaller than AAPL, IBM
getSymbols("DJI") # Dow Jones, huge
chart_Series(Cl(AAPL), TA="add_TA(Cl(IBM), col='blue', on=1); add_TA(Cl(CSCO), col = 'green', on=1)",
    col='orange', subset = '2017::2017-08')


==== Create a static library <libRmath.a> and a dynamic library <Rmath.dll> ====
tail(Cl(DJI))
Suppose we have downloaded R source code and build R from its source. See [[R#Build_R_from_its_source|Build_R_from_its_source]]. Then the following 2 lines will generate files <libRmath.a> and <Rmath.dll> under C:\R\R-3.0.2\src\nmath\standalone directory.
</pre>
<pre>
 
cd C:\R\R-3.0.2\src\nmath\standalone
=== tidyquant: Getting stock data ===
make -f Makefile.win
[http://varianceexplained.org/r/stock-changes/ The 'largest stock profit or loss' puzzle: efficient computation in R]
</pre>
 
=== Timeline plot ===
* https://stackoverflow.com/questions/20695311/chronological-timeline-with-points-in-time-and-format-date
* [https://github.com/shosaco/vistime vistime] - Pretty Timelines in R
 
=== Clockify ===
[https://datawookie.dev/blog/2021/09/clockify-time-tracking-from-r/ Clockify]


==== Use Rmath library in our code ====
== Circular plot ==
<pre>
* http://freakonometrics.hypotheses.org/20667 which uses [https://cran.r-project.org/web/packages/circlize/ circlize] package; see also the '''ComplexHeatmap''' package.
set CPLUS_INCLUDE_PATH=C:\R\R-3.0.2\src\include
* https://www.biostars.org/p/17728/
set LIBRARY_PATH=C:\R\R-3.0.2\src\nmath\standalone
* [https://cran.r-project.org/web/packages/RCircos/ RCircos] package from CRAN.
# It is not LD_LIBRARY_PATH in above.
* [http://www.bioconductor.org/packages/release/bioc/html/OmicCircos.html OmicCircos] from Bioconductor.


# Created <RmathEx1.cpp> from the book "Statistical Computing in C++ and R" web site
== Word cloud ==
# http://math.la.asu.edu/~eubank/CandR/ch4Code.cpp
* [http://www.sthda.com/english/wiki/text-mining-and-word-cloud-fundamentals-in-r-5-simple-steps-you-should-know Text mining and word cloud fundamentals in R : 5 simple steps you should know]
# It is OK to save the cpp file under any directory.
* [https://www.displayr.com/alternatives-word-cloud/ 7 Alternatives to Word Clouds for Visualizing Long Lists of Data]
* [https://www.littlemissdata.com/blog/steam-data-art1 Data + Art STEAM Project: Initial Results]
* [https://github.com/lepennec/ggwordcloud?s=09 ggwordcloud]


# Force to link against the static library <libRmath.a>
== Text mining ==
g++ RmathEx1.cpp -lRmath -lm -o RmathEx1.exe
* [https://cran.r-project.org/web/packages/tm/index.html tm] package. It was used by [https://github.com/jtleek/swfdr/blob/master/getPvalues.R R code] of [https://doi.org/10.1093/biostatistics/kxt007 An estimate of the science-wise false discovery rate and application to the top medical literature].
# OR
g++ RmathEx1.cpp -Wl,-Bstatic -lRmath -lm -o RmathEx1.exe


# Force to link against dynamic library <Rmath.dll>
== World map ==
g++ RmathEx1.cpp Rmath.dll -lm -o RmathEx1Dll.exe
[https://www.enchufa2.es/archives/visualising-ssh-attacks-with-r.html Visualising SSH attacks with R] ([https://cran.r-project.org/package=rworldmap rworldmap] and [https://cran.r-project.org/package=rgeolocate rgeolocate] packages)
</pre>
Test the executable program. Note that the executable program ''RmathEx1.exe'' can be transferred to and run in another computer without R installed. Isn't it cool!
<pre>
c:\R>RmathEx1
Enter a argument for the normal cdf:
1
Enter a argument for the chi-squared cdf:
1
Prob(Z <= 1) = 0.841345
Prob(Chi^2 <= 1)= 0.682689
</pre>


Below is the cpp program <RmathEx1.cpp>.
== Diagram/flowchart/Directed acyclic diagrams (DAGs) ==
<pre>
* [https://finnstats.com/index.php/2021/06/29/transition-plot-in-r-change-in-time-visualization/ Transition plot in R-change in time visualization]
//RmathEx1.cpp
 
#define MATHLIB_STANDALONE
=== [https://cran.r-project.org/web/packages/DiagrammeR/index.html DiagrammeR] ===
#include <iostream>
* [https://blog.rstudio.com/2015/05/01/rstudio-v0-99-preview-graphviz-and-diagrammer/ Graphviz and DiagrammeR]
#include "Rmath.h"
* http://rich-iannone.github.io/DiagrammeR/,
** [http://rich-iannone.github.io/DiagrammeR/io.html#r-markdown rmarkdown]
** [http://rich-iannone.github.io/DiagrammeR/graphviz_and_mermaid.html graphviz and mermaid] doc and examples
* https://donlelek.github.io/2015-03-31-dags-with-r/
* [https://mikeyharper.uk/flowcharts-in-r-using-diagrammer/ Data-driven flowcharts in R using DiagrammeR]
 
=== [https://cran.r-project.org/web/packages/diagram/ diagram] ===
Functions for Visualising Simple Graphs (Networks), Plotting Flow Diagrams


using std::cout; using std::cin; using std::endl;
=== DAGitty (browser-based and R package) ===
* http://dagitty.net/
* https://cran.r-project.org/web/packages/dagitty/index.html


int main()
=== dagR ===
{
* https://cran.r-project.org/web/packages/dagR
  double x1, x2;
  cout << "Enter a argument for the normal cdf:" << endl;
  cin >> x1;
  cout << "Enter a argument for the chi-squared cdf:" << endl;
  cin >> x2;


  cout << "Prob(Z <= " << x1 << ") = " <<
=== Gmisc ===
    pnorm(x1, 0, 1, 1, 0)  << endl;
[http://gforge.se/2020/08/easy-flowchart/ Easiest flowcharts eveR?]
  cout << "Prob(Chi^2 <= " << x2 << ")= " <<
    pchisq(x2, 1, 1, 0) << endl;
  return 0;
}
</pre>


=== Calling R.dll directly ===
=== Concept Maps ===
See Chapter 8.2.2 of [http://cran.r-project.org/doc/manuals/R-exts.html#Calling-R_002edll-directly|Writing R Extensions]. This is related to embedding R under Windows. The file <R.dll> on Windows is like <libR.so> on Linux.
[https://github.com/rstudio/concept-maps/ concept-maps] where the diagrams are generated from https://app.diagrams.net/.


=== Create HTML 5 web and slides ===
=== flow ===
See [[#Create HTML5 web and slides|here]]
[https://cran.r-project.org/web/packages/flow/ flow], [https://predictivehacks.com/?all-tips=how-to-draw-flow-diagrams-in-r How To Draw Flow Diagrams In R]


=== Scheduling R Markdown Reports via Email ===
== Venn Diagram ==
http://www.analyticsforfun.com/2016/01/scheduling-r-markdown-reports-via-email.html
[[Venn_diagram|Venn diagram]]


=== Create presentation file (beamer) ===
== hexbin plot ==
* http://rmarkdown.rstudio.com/beamer_presentation_format.html
* [https://datasciencetut.com/how-to-create-a-hexbin-chart-in-r/ How to create a hexbin chart in R]
* http://www.theresearchkitchen.com/archives/1017 (markdown and presentation files)
* [https://cran.r-project.org/web/packages/hextri/index.html hextri]: Hexbin Plots with Triangles. See an example on this https://www.pnas.org/content/117/48/30266#F4 paper] about the postpi method.
* http://rmarkdown.rstudio.com/


# Create Rmd file first in Rstudio by File -> R markdown. Select Presentation > choose pdf (beamer) as output format.
== Bump chart/Metro map ==
# Edit the template created by RStudio.
https://dominikkoch.github.io/Bump-Chart/
# Click 'Knit pdf' button (Ctrl+Shift+k) to create/display the pdf file.


An example of Rmd is
== Amazing/special plots ==
<pre>
See [[Amazing_plot|Amazing plot]].
---
title: "My Example"
author: You Know Me
date: Dec 32, 2014
output: beamer_presentation
---


## R Markdown
== Google Analytics ==
=== GAR package ===
http://www.analyticsforfun.com/2015/10/query-your-google-analytics-data-with.html


This is an R Markdown presentation. Markdown is a simple formatting syntax for authoring HTML, PDF, and MS Word documents.
== Linear Programming ==
For more details on using R Markdown see <http://rmarkdown.rstudio.com>.
http://www.r-bloggers.com/modeling-and-solving-linear-programming-with-r-free-book/


When you click the **Knit** button a document will be generated that includes both content as well as the output of any
== Linear Algebra ==
embedded R code chunks within the document.
* [https://jimskinner.github.io/post/elegant-linear-algebra-in-r-with-the-matrix-package/ Elegant linear algebra in R with the Matrix package]. Matrix package is used.
* [https://datascienceplus.com/linear-algebra-for-machine-learning-and-deep-learning-in-r/ Linear Algebra for Machine Learning and Deep Learning in R]. MASS library is used.


## Slide with Bullets
== Amazon Alexa ==
* http://blagrants.blogspot.com/2016/02/theres-party-at-alexas-place.html


- Bullet 1
== R and Singularity ==
- Bullet 2
https://rviews.rstudio.com/2017/03/29/r-and-singularity/
- Bullet 3. Mean is $\frac{1}{n} \sum_{i=1}^n x_i$.
$$
\mu = \frac{1}{n} \sum_{i=1}^n x_i
$$


## New slide
== Teach kids about R with Minecraft ==
http://blog.revolutionanalytics.com/2017/06/teach-kids-about-r-with-minecraft.html


![picture of BDGE](/home/brb/Pictures/BDGEFinished.png)
== Secure API keys ==
[http://blog.revolutionanalytics.com/2017/07/secret-package.html Securely store API keys in R scripts with the "secret" package]


## Slide with R Code and Output
== Credentials and secrets ==
[https://datascienceplus.com/how-to-manage-credentials-and-secrets-safely-in-r/ How to manage credentials and secrets safely in R]


```{r}
== Hide a password ==
summary(cars)
=== keyring package ===
```
* https://cran.r-project.org/web/packages/keyring/index.html
* [http://theautomatic.net/2019/06/25/how-to-hide-a-password-in-r-with-the-keyring-package/ How to hide a password in R with the Keyring package]


## Slide with Plot
=== getPass ===
[https://cran.r-project.org/web/packages/getPass/README.html getPass]


```{r, echo=FALSE}
== Vision and image recognition ==
plot(cars)
* https://www.stoltzmaniac.com/google-vision-api-in-r-rooglevision/ Google vision API IN R] – RoogleVision
```
* [http://www.bnosac.be/index.php/blog/66-computer-vision-algorithms-for-r-users Computer Vision Algorithms for R users] and https://github.com/bnosac/image
</pre>


=== Create HTML report ===
== Creating a Dataset from an Image ==
[http://www.bioconductor.org/packages/release/bioc/html/ReportingTools.html ReportingTools] (Jason Hackney) from Bioconductor.
[https://ivelasq.rbind.io/blog/reticulate-data-recreation/ Creating a Dataset from an Image in R Markdown using reticulate]


==== [http://cran.r-project.org/web/packages/htmlTable/index.html htmlTable] package ====
== Turn pictures into coloring pages ==
The htmlTable package is intended for generating tables using HTML formatting. This format is compatible with Markdown when used for HTML-output. The most basic table can easily be created by just passing a matrix or a data.frame to the htmlTable-function.
https://gist.github.com/jeroen/53a5f721cf81de2acba82ea47d0b19d0


* http://cran.r-project.org/web/packages/htmlTable/vignettes/general.html
== Numerical optimization ==
* http://gforge.se/2014/01/fast-track-publishing-using-knitr-part-iv/
[https://cran.r-project.org/web/views/NumericalMathematics.html CRAN Task View: Numerical Mathematics], [https://cran.r-project.org/web/views/Optimization.html CRAN Task View: Optimization and Mathematical Programming]


==== formattable ====
* [http://stat.ethz.ch/R-manual/R-patched/library/stats/html/uniroot.html uniroot]: One Dimensional Root (Zero) Finding. This is used in [http://onlinelibrary.wiley.com/doi/10.1002/sim.7178/full simulating survival data for predefined censoring rate]
http://www.magesblog.com/2016/01/formatting-table-output-in-r.html
* [http://stat.ethz.ch/R-manual/R-patched/library/stats/html/optimize.html optimize]: One Dimensional Optimization
==== [https://github.com/crubba/htmltab htmltab] package ====
* [http://stat.ethz.ch/R-manual/R-patched/library/stats/html/optim.html optim]: General-purpose optimization based on Nelder–Mead, quasi-Newton and conjugate-gradient algorithms.
This package is NOT used to CREATE html report but EXTRACT html table.
* [http://stat.ethz.ch/R-manual/R-patched/library/stats/html/constrOptim.html constrOptim]: Linearly Constrained Optimization
* [http://stat.ethz.ch/R-manual/R-patched/library/stats/html/nlm.html nlm]: Non-Linear Minimization
* [http://stat.ethz.ch/R-manual/R-patched/library/stats/html/nls.html nls]: Nonlinear Least Squares
* [https://blogs.rstudio.com/ai/posts/2021-04-22-torch-for-optimization/ torch for optimization]. L-BFGS optimizer.


==== [http://cran.r-project.org/web/packages/ztable/index.html ztable] package ====
== Ryacas: R Interface to the 'Yacas' Computer Algebra System ==
Makes zebra-striped tables (tables with alternating row colors) in LaTeX and HTML formats easily from a data.frame, matrix, lm, aov, anova, glm or coxph objects.
[https://blog.ephorie.de/doing-maths-symbolically-r-as-a-computer-algebra-system-cas Doing Maths Symbolically: R as a Computer Algebra System (CAS)]


=== Create academic report ===
== Game ==
[http://cran.r-project.org/web/packages/reports/index.html reports] package in CRAN and in [https://github.com/trinker/reports github] repository. The youtube video gives an overview of the package.
* [https://kbroman.org/miner_book/?s=09 R Programming with Minecraft]
* [https://cran.r-project.org/web/packages/pixelpuzzle/index.html pixelpuzzle]
* [https://www.rostrum.blog/2022/09/24/pixeltrix/ Interactive pixel art in R with {pixeltrix}]
* [https://rtaoist.blogspot.com/2021/03/r-shiny-maths-games-for-6-years-old.html Shiny math game]
* [https://cran.microsoft.com/web/packages/mazing/index.html mazing]: Utilities for Making and Plotting Mazes
* [https://github.com/jeroenjanssens/raylibr/blob/main/demo/snake.R snake] which is based on [https://github.com/jeroenjanssens/raylibr raylibr]


=== Create pdf and epub files ===
== Music ==
<syntaxhighlight lang='rsplus'>
* [https://flujoo.github.io/gm/ gm]. Require to install [https://musescore.org/en MuseScore], an open source and free notation software.
# Idea:
#        knitr        pdflatex
#  rnw -------> tex ----------> pdf
library(knitr)
knit("example.rnw") # create example.tex file
</syntaxhighlight>
* A very simple example <002-minimal.Rnw> from [http://yihui.name/knitr/demo/minimal/ yihui.name] works fine on linux.
<syntaxhighlight lang='bash'>
git clone https://github.com/yihui/knitr-examples.git
</syntaxhighlight>
* <knitr-minimal.Rnw>. I have no problem to create pdf file on Windows but still cannot generate pdf on Linux from tex file. Some people suggested to run '''sudo apt-get install texlive-fonts-recommended''' to install missing fonts. It works!


To see a real example, check out [http://www.bioconductor.org/packages/release/bioc/html/DESeq2.html DESeq2] package (inst/doc subdirectory). In addition to DESeq2, I also need to install '''DESeq, BiocStyle, airway, vsn, gplots''', and '''pasilla''' packages from Bioconductor. Note that, it is best to use sudo/admin account to install packages.
== SAS ==
[https://github.com/MangoTheCat/sasMap sasMap] Static code analysis for SAS scripts


Or starts with markdown file. Download the example <001-minimal.Rmd> and remove the last line of getting png file from internet.
= R packages =
<syntaxhighlight lang='bash'>
[[R_packages|R packages]]
# Idea:
#        knitr        pandoc
#  rmd -------> md ----------> pdf


git clone https://github.com/yihui/knitr-examples.git
= Tricks =
cd knitr-examples
R -e "library(knitr); knit('001-minimal.Rmd')"
pandoc 001-minimal.md -o 001-minimal.pdf # require pdflatex to be installed !!
</syntaxhighlight>


To create an epub file (not success yet on Windows OS, missing figures on Linux OS)
== Getting help ==
<syntaxhighlight lang='rsplus'>
* http://stackoverflow.com/questions/tagged/r and [https://stackoverflow.com/tags/r/info R page] contains resources.
# Idea:
* https://stat.ethz.ch/pipermail/r-help/
#        knitr        pandoc
* https://stat.ethz.ch/pipermail/r-devel/
#  rnw -------> tex ----------> markdown or epub


library(knitr)
== Better Coder/coding, best practices ==
knit("DESeq2.Rnw") # create DESeq2.tex
* http://www.mango-solutions.com/wp/2015/10/10-top-tips-for-becoming-a-better-coder/
system("pandoc  -f latex -t markdown -o DESeq2.md DESeq2.tex")
* [https://www.rstudio.com/rviews/2016/12/02/writing-good-r-code-and-writing-well/ Writing Good R Code and Writing Well]
</syntaxhighlight>
* [http://www.thertrader.com/2018/09/01/r-code-best-practices/ R Code – Best practices]
<pre>
* [https://stackoverflow.com/a/2258292 What best practices do you use for programming in R?]
## Windows OS, epub cannot be built
* [https://onlinelibrary.wiley.com/doi/abs/10.1002/sim.9169?campaign=woletoc Best practices in statistical computing] Sanchez 2021
pandoc:
Error:
"source" (line 41, column 7):
unexpected "k"
expecting "{document}"


## Linux OS, epub missing figures and R codes.
== [https://en.wikipedia.org/wiki/Scientific_notation#E-notation E-notation] ==
## First install texlive base and extra packages
6.022E23 (or 6.022e23) is equivalent to 6.022×10^23
## sudo apt-get install texlive-latex-base texlive-latex-extra
pandoc: Could not find media `figure/SchwederSpjotvoll-1', skipping...
pandoc: Could not find media `figure/sortedP-1', skipping...
pandoc: Could not find media `figure/figHeatmap2c-1', skipping...
pandoc: Could not find media `figure/figHeatmap2b-1', skipping...
pandoc: Could not find media `figure/figHeatmap2a-1', skipping...
pandoc: Could not find media `figure/plotCountsAdv-1', skipping...
pandoc: Could not find media `figure/plotCounts-1', skipping...
pandoc: Could not find media `figure/MA-1', skipping...
pandoc: Could not find media `figure/MANoPrior-1', skipping...
</pre>
The problems are at least
* figures need to be generated under the same directory as the source code
* figures cannot be in the format of pdf (DESeq2 generates both pdf and png files format)
* missing R codes


Convert tex to epub
== Getting user's home directory ==
* http://tex.stackexchange.com/questions/156668/tex-to-epub-conversion
See [https://cran.r-project.org/bin/windows/base/rw-FAQ.html#What-are-HOME-and-working-directories_003f What are HOME and working directories?]
{{Pre}}
# Windows
normalizePath("~")  # "C:\\Users\\brb\\Documents"
Sys.getenv("R_USER") # "C:/Users/brb/Documents"
Sys.getenv("HOME")  # "C:/Users/brb/Documents"


=== Create Word report ===
# Mac
normalizePath("~")  # [1] "/Users/brb"
Sys.getenv("R_USER") # [1] ""
Sys.getenv("HOME")  # "/Users/brb"


==== knitr + pandoc ====
# Linux
* http://www.r-statistics.com/2013/03/write-ms-word-document-using-r-with-as-little-overhead-as-possible/
normalizePath("~")  # [1] "/home/brb"
* http://www.carlboettiger.info/2012/04/07/writing-reproducibly-in-the-open-with-knitr.html
Sys.getenv("R_USER") # [1] ""
* http://rmarkdown.rstudio.com/articles_docx.html
Sys.getenv("HOME")  # [1] "/home/brb"
</pre>
 
== tempdir() ==
* The path is a per-session temporary directory. On parallel use, R processes forked by functions such as '''mclapply''' and '''makeForkCluster''' in package '''parallel''' share a per-session temporary directory.
* [https://www.r-bloggers.com/2024/07/r-set-temporary-folder-for-r-in-rstudio-server/ Set temporary folder for R in Rstudio server]
 
== Distinguish Windows and Linux/Mac, R.Version() ==
identical(.Platform$OS.type, "unix") returns TRUE on Mac and Linux.


It is better to create rmd file in RStudio. Rstudio provides a template for rmd file and it also provides a quick reference to R markdown language.
* [https://www.r-bloggers.com/identifying-the-os-from-r/ Identifying the OS from R]
* [https://stackoverflow.com/questions/4747715/how-to-check-the-os-within-r How to check the OS within R]
<pre>
<pre>
# Idea:
get_os <- function(){
#        knitr      pandoc
  sysinf <- Sys.info()
#   rmd -------> md --------> docx
   if (!is.null(sysinf)){
library(knitr)
    os <- sysinf['sysname']
knit2html("example.rmd") #Create md and html files
    if (os == 'Darwin')
      os <- "osx"
  } else { ## mystery machine
    os <- .Platform$OS.type
    if (grepl("^darwin", R.version$os))
      os <- "osx"
    if (grepl("linux-gnu", R.version$os))
      os <- "linux"
  }
  tolower(os)
}
</pre>
</pre>
and then
<pre>
<pre>
FILE <- "example"
names(R.Version())
system(paste0("pandoc -o ", FILE, ".docx ", FILE, ".md"))
#  [1] "platform"      "arch"          "os"             "system"       
#  [5] "status"        "major"          "minor"          "year"         
#  [9] "month"          "day"            "svn rev"        "language"    
# [13] "version.string" "nickname"  
getRversion()
# [1] ‘4.3.0’
</pre>
</pre>
Note. For example reason, if I play around the above 2 commands for several times, the knit2html() does not work well. However, if I click 'Knit HTML' button on the RStudio, it then works again.


Another way is
== Rprofile.site, Renviron.site (all platforms) and Rconsole (Windows only) ==
* https://cran.r-project.org/doc/manuals/r-release/R-admin.html ('''Rprofile.site'''). Put R statements.
* https://cran.r-project.org/doc/manuals/r-release/R-exts.html  ('''Renviron.site'''). Define environment variables.
* https://cran.r-project.org/doc/manuals/r-release/R-intro.html ('''Rprofile.site, Renviron.site, Rconsole''' (Windows only))
* [http://blog.revolutionanalytics.com/2015/11/how-to-store-and-use-authentication-details-with-r.html How to store and use webservice keys and authentication details]
* [http://itsalocke.com/use-rprofile-give-important-notifications/ Use your .Rprofile to give you important notifications]
* [https://rviews.rstudio.com/2017/04/19/r-for-enterprise-understanding-r-s-startup/ *R for Enterprise: Understanding R’s Startup]
* [https://support.rstudio.com/hc/en-us/articles/360047157094-Managing-R-with-Rprofile-Renviron-Rprofile-site-Renviron-site-rsession-conf-and-repos-conf *Managing R with .Rprofile, .Renviron, Rprofile.site, Renviron.site, rsession.conf, and repos.conf]
 
If we like to install R packages to a personal directory, follow [https://stat.ethz.ch/pipermail/r-devel/2015-July/071562.html this]. Just add the line
<pre>
<pre>
library(pander)
R_LIBS_SITE=F:/R/library
name = "demo"
knit(paste0(name, ".Rmd"), encoding = "utf-8")
Pandoc.brew(file = paste0(name, ".md"), output = paste0(-name, "docx"), convert = "docx")
</pre>
</pre>
to the file '''R_HOME/etc/x64/Renviron.site'''. In R, run '''Sys.getenv("R_LIBS_SITE")''' or '''Sys.getenv("R_LIBS_USER")''' to query the environment variable. See [https://stat.ethz.ch/R-manual/R-devel/library/base/html/EnvVar.html Environment Variables].


Note that once we have used knitr command to create a md file, we can use pandoc shell command to convert it to different formats:
=== What is the best place to save Rconsole on Windows platform ===
* A pdf file: pandoc -s report.md -t latex -o report.pdf
Put/create the file <Rconsole> under ''C:/Users/USERNAME/Documents'' folder so no matter how R was upgraded/downgraded, it always find my preference.
* A html file: pandoc -s report.md -o report.html (with the -c flag html files can be added easily)
 
* Openoffice: pandoc report.md -o report.odt
My preferred settings:
* Word docx: pandoc report.md -o report.docx
* Font: Consolas (it will be shown as "TT Consolas" in Rconsole)
* Size: 12
* background: black
* normaltext: white
* usertext: GreenYellow or orange (close to RStudio's Cobalt theme) or sienna1 or SpringGreen or tan1 or yellow


We can also create the epub file for reading on Kobo ereader. For example, download [https://gist.github.com/jeromyanglim/2716336 this file] and save it as example.Rmd. I need to remove the line containing the link to http://i.imgur.com/RVNmr.jpg since it creates an error when I run pandoc (not sure if it is the pandoc version I have is too old). Now we just run these 2 lines to get the epub file. Amazing!
and others (default options)
* pagebg: white
* pagetext: navy
* highlight: DarkRed
* dataeditbg: white
* dataedittext: navy (View() function)
* dataedituser: red
* editorbg: white (edit() function)
* editortext: black
 
A copy of the Rconsole is saved in [https://gist.github.com/arraytools/ed16a486e19702ae94bde4212ad59ecb github].
 
=== How R starts up ===
https://rstats.wtf/r-startup.html
 
=== startup - Friendly R Startup Configuration ===
https://github.com/henrikbengtsson/startup
 
== Saving and loading history automatically: .Rprofile & local() ==
<ul>
<li>[http://stat.ethz.ch/R-manual/R-patched/library/utils/html/savehistory.html savehistory("filename")]. It will save everything from the beginning to the command savehistory() to a text file.
<li>'''.Rprofile''' will automatically be loaded when R has started from that directory
<li>Don't do things in your .Rprofile that affect how R code runs, such as loading a package like dplyr or ggplot or setting an option such as stringsAsFactors = FALSE. See [https://www.tidyverse.org/articles/2017/12/workflow-vs-script/ Project-oriented workflow].
<li>'''.Rprofile''' has been created/used by the '''packrat''' package to restore a packrat environment. See the packrat/init.R file and [[R_packages|R packages &rarr; packrat]].
<li>[http://www.statmethods.net/interface/customizing.html Customizing Startup] from R in Action, [http://www.onthelambda.com/2014/09/17/fun-with-rprofile-and-customizing-r-startup/ Fun with .Rprofile and customizing R startup]
* You can also place a '''.Rprofile''' file in any directory that you are going to run R from or in the user home directory.
* At startup, R will source the '''Rprofile.site''' file. It will then look for a '''.Rprofile''' file to source in the current working directory. If it doesn't find it, it will look for one in the user's home directory.
<pre>
options(continue="  ") # default is "+ "
options(prompt="R> ", continue=" ")
options(editor="nano") # default is "vi" on Linux
# options(htmlhelp=TRUE)
 
local({r <- getOption("repos")
      r["CRAN"] <- "https://cran.rstudio.com"
      options(repos=r)})
 
.First <- function(){
# library(tidyverse)
cat("\nWelcome at", date(), "\n")
}
 
.Last <- function(){
cat("\nGoodbye at ", date(), "\n")
</pre>
<li>https://stackoverflow.com/questions/16734937/saving-and-loading-history-automatically
<li>The history file will always be read from the $HOME directory and the history file will be overwritten by a new session. These two problems can be solved if we define '''R_HISTFILE''' system variable.
<li>[https://www.rdocumentation.org/packages/base/versions/3.5.0/topics/eval local()] function can be used in .Rprofile file to set up the environment even no new variables will be created (change repository, install packages, load libraries, source R files, run system() function, file/directory I/O, etc)
</ul>
'''Linux''' or '''Mac'''
 
In '''~/.profile''' or '''~/.bashrc''' I put:
<pre>
<pre>
knit("example.Rmd")
export R_HISTFILE=~/.Rhistory
pandoc("example.md", format="epub")
</pre>
</pre>
 
In '''~/.Rprofile''' I put:
PS. If we don't remove the link, we will get an error message (pandoc 1.10.1 on Windows 7)
<pre>
<pre>
> pandoc("Rmd_to_Epub.md", format="epub")
if (interactive()) {
executing pandoc   -f markdown -t epub -o Rmd_to_Epub.epub "Rmd_to_Epub.utf8md"
   if (.Platform$OS.type == "unix".First <- function() try(utils::loadhistory("~/.Rhistory"))
pandoc.exe: .\.\http://i.imgur.com/RVNmr.jpg: openBinaryFile: invalid argument (Invalid argument)
  .Last <- function() try(savehistory(file.path(Sys.getenv("HOME"), ".Rhistory")))
Error in (function (input, format, ext, cfg)  : conversion failed
}
In addition: Warning message:
running command 'pandoc  -f markdown -t epub -o Rmd_to_Epub.epub "Rmd_to_Epub.utf8md"' had status 1
</pre>
</pre>


==== pander ====
'''Windows'''
Try pandoc[1] with a minimal reproducible example, you might give a try to my "[http://cran.r-project.org/web/packages/pander/ pander]" package [2] too:


If you launch R by clicking its icon from Windows Desktop, the R starts in '''C:\User\$USER\Documents''' directory. So we can create a new file '''.Rprofile''' in this directory.
<pre>
<pre>
library(pander)
if (interactive()) {
Pandoc.brew(system.file('examples/minimal.brew', package='pander'),
  .Last <- function() try(savehistory(file.path(Sys.getenv("HOME"), ".Rhistory")))
            output = tempfile(), convert = 'docx')
}
</pre>
</pre>
Where the content of the "minimal.brew" file is something you might have
got used to with Sweave - although it's using "brew" syntax instead. See
the examples of pander [3] for more details. Please note that pandoc should
be installed first, which is pretty easy on Windows.


# http://johnmacfarlane.net/pandoc/
== Disable "Save workspace image?" prompt when exit R? ==
# http://rapporter.github.com/pander/
[https://stackoverflow.com/a/4996252 How to disable "Save workspace image?" prompt in R?]
# http://rapporter.github.com/pander/#examples
 
== R release versions ==
[http://cran.r-project.org/web/packages/rversions/index.html rversions]: Query the main 'R' 'SVN' repository to find the released versions & dates.


==== R2wd ====
== getRversion() ==
Use [http://cran.r-project.org/web/packages/R2wd/ R2wd] package. However, only 32-bit R is allowed and sometimes it can not produce all 'table's.
<pre>
<pre>
> library(R2wd)
getRversion()
> wdGet()
[1] ‘4.3.0’
Loading required package: rcom
Loading required package: rscproxy
rcom requires a current version of statconnDCOM installed.
To install statconnDCOM type
    installstatconnDCOM()
 
This will download and install the current version of statconnDCOM
 
You will need a working Internet connection
because installation needs to download a file.
Error in if (wdapp[["Documents"]][["Count"]] == 0) wdapp[["Documents"]]$Add() :
  argument is of length zero
</pre>
</pre>


The solution is to launch 32-bit R instead of 64-bit R since statconnDCOM does not support 64-bit R.
== Detect number of running R instances in Windows ==
* http://stackoverflow.com/questions/15935931/detect-number-of-running-r-instances-in-windows-within-r
<pre>
C:\Program Files\R>tasklist /FI "IMAGENAME eq Rscript.exe"
INFO: No tasks are running which match the specified criteria.


==== Convert from pdf to word ====
C:\Program Files\R>tasklist /FI "IMAGENAME eq Rgui.exe"
The best rendering of advanced tables is done by converting from pdf to Word. See http://biostat.mc.vanderbilt.edu/wiki/Main/SweaveConvert


==== rtf ====
Image Name                    PID Session Name        Session#    Mem Usage
Use [http://cran.r-project.org/web/packages/rtf/ rtf] package for Rich Text Format (RTF) Output.
============================================================================
Rgui.exe                      1096 Console                    1    44,712 K


==== xtable ====
C:\Program Files\R>tasklist /FI "IMAGENAME eq Rserve.exe"
Package xtable will produce html output. If you save the file and then open it with Word, you will get serviceable results. I've had better luck copying the output from xtable and pasting it into Excel.


==== [http://cran.r-project.org/web/packages/ReporteRs/index.html ReporteRs] ====
Image Name                    PID Session Name        Session#    Mem Usage
Microsoft Word, Microsoft Powerpoint and HTML documents generation from R. The source code is hosted on https://github.com/davidgohel/ReporteRs
============================================================================
Rserve.exe                    6108 Console                    1    381,796 K
</pre>
In R, we can use
<pre>
> system('tasklist /FI "IMAGENAME eq Rgui.exe" ', intern = TRUE)
[1] ""                                                                           
[2] "Image Name                    PID Session Name        Session#    Mem Usage"
[3] "============================================================================"
[4] "Rgui.exe                      1096 Console                    1    44,804 K"


=== R Graphs Gallery ===
> length(system('tasklist /FI "IMAGENAME eq Rgui.exe" ', intern = TRUE))-3
* [https://www.facebook.com/pages/R-Graph-Gallery/169231589826661 Romain François]
</pre>
* [http://shinyapps.stat.ubc.ca/r-graph-catalog/ R Graph Catalog] written using R + Shiny. The source code is available on [https://github.com/jennybc/r-graph-catalog Github].
 
== Editor ==
http://en.wikipedia.org/wiki/R_(programming_language)#Editors_and_IDEs
 
<ul>
<li>Emacs + ESS. The ESS is useful in the case I want to tidy R code (the tidy_source() function in the formatR package sometimes gives errors; eg when I tested it on an R file like <GetComparisonResults.R> from BRB-ArrayTools v4.4 stable).
* Edit the file ''C:\Program Files\GNU Emacs 23.2\site-lisp\site-start.el'' with something like
<pre>
(setq-default inferior-R-program-name
              "c:/program files/r/r-2.15.2/bin/i386/rterm.exe")
</pre>
* [https://blog.rwhitedwarf.com/post/use_emacs_for_r/ Using Emacs for R] 2022
</ul>
* [http://www.rstudio.com/ Rstudio] - editor/R terminal/R graphics/file browser/package manager. The new version (0.98) also provides a new feature for debugging step-by-step. See also [https://www.rstudio.com/rviews/2016/11/11/easy-tricks-you-mightve-missed/ RStudio Tricks]
* [http://www.geany.org/ geany] - I like the feature that it shows defined functions on the side panel even for R code. RStudio can also do this (see the bottom of the code panel).
* [http://rgedit.sourceforge.net/ Rgedit] which includes a feature of splitting screen into two panes and run R in the bottom panel. See [http://www.stattler.com/article/using-gedit-or-rgedit-r here].
* Komodo IDE with browser preview http://www.youtube.com/watch?v=wv89OOw9roI at 4:06 and http://docs.activestate.com/komodo/4.4/editor.html


=== COM client or server ===
== GUI for Data Analysis ==
[https://www.r-bloggers.com/2023/06/update-to-data-science-software-popularity/ Update to Data Science Software Popularity] 6/7/2023


==== Client ====
=== BlueSky Statistics ===
* https://www.blueskystatistics.com/Default.asp
* [https://r4stats.com/articles/software-reviews/bluesky/ A Comparative Review of the BlueSky Statistics GUI for R]


[http://www.omegahat.org/RDCOMClient/ RDCOMClient] where [http://cran.r-project.org/web/packages/excel.link/index.html excel.link] depends on it.
=== Rcmdr ===
http://cran.r-project.org/web/packages/Rcmdr/index.html. After loading a dataset, click Statistics -> Fit models. Then select Linear regression, Linear model, GLM, Multinomial logit model, Ordinal regression model, Linear mixed model, and Generalized linear mixed model. However, Rcmdr does not include, e.g. random forest, SVM, glmnet, et al.


==== Server ====
=== Deducer ===
[http://www.omegahat.org/RDCOMServer/ RDCOMServer]
http://cran.r-project.org/web/packages/Deducer/index.html


=== Use R under proxy ===
=== jamovi ===
http://support.rstudio.org/help/kb/faq/configuring-r-to-use-an-http-proxy
* https://www.jamovi.org/
* [http://r4stats.com/2019/01/09/updated-review-jamovi/ Updated Review: jamovi User Interface to R]


=== What is the best place to save Rconsole on Windows platform ===
== Scope ==
Put it in ''C:/Users/USERNAME/Documents'' folder so no matter how R was upgraded/downgraded, it always find my preference.
See
* [http://cran.r-project.org/doc/manuals/R-intro.html#Assignment-within-functions Assignments within functions] in the '''An Introduction to R''' manual.


=== Web scraping ===
=== source() ===
http://www.slideshare.net/schamber/web-data-from-r#btnNext
* [https://twitter.com/henrikbengtsson/status/1563849697084809219?s=20&t=nStcqVabAQ_HvJ2FaBloNQ source() assigns to the global environment, not the calling environment, which might not be what you want/expect]. Instead, use source("file.R", local = TRUE) to avoid assigning functions and variables to the global environment.
* [[#How_to_exit_a_sourced_R_script|source()]] does not work like C's preprocessor where statements in header files will be literally inserted into the code. It does not work when you define a variable in a function but want to use it outside the function (even through '''source()''')


==== [http://cran.r-project.org/web/packages/pubmed.mineR/index.html pubmed.mineR] ====
{{Pre}}
Text mining of PubMed Abstracts (http://www.ncbi.nlm.nih.gov/pubmed). The algorithms are designed for two formats (text and XML) from PubMed.
## foo.R ##
cat(ArrayTools, "\n")
## End of foo.R


=== Launch Rstudio ===
# 1. Error
If multiple versions of R was detected, Rstudio can not be launched successfully. A java-like clock will be spinning without a stop. The trick is to click Ctrl key and click the Rstudio at the same time.
predict <- function() {
After done that, it will show up a selection of R to choose from.
  ArrayTools <- "C:/Program Files" # or through load() function
  source("foo.R")                  # or through a function call; foo()
}
predict()  # Object ArrayTools not found


[[File:RStudio.jpg|100px]]
# 2. OK. Make the variable global
predict <- function() {
  ArrayTools <<- "C:/Program Files'
  source("foo.R")
}
predict() 
ArrayTools


=== List files using regular expression ===
# 3. OK. Create a global variable
* Extension
ArrayTools <- "C:/Program Files"
<pre>
predict <- function() {
list.files(pattern = "\\.txt$")
  source("foo.R")
</pre>
}
where the dot (.) is a metacharacter. It is used to refer to any character.
predict()
* Start with
<pre>
list.files(pattern = "^Something")
</pre>
</pre>


Using '''Sys.glob()"' as
'''Note that any ordinary assignments done within the function are local and temporary and are lost after exit from the function.'''
<pre>
> Sys.glob("~/Downloads/*.txt")
[1] "/home/brb/Downloads/ip.txt"      "/home/brb/Downloads/valgrind.txt"
</pre>


=== Hidden tool: rsync in Rtools ===
Example 1.
<pre>
<pre>
c:\Rtools\bin>rsync -avz "/cygdrive/c/users/limingc/Downloads/a.exe" "/cygdrive/c/users/limingc/Documents/"
> ttt <- data.frame(type=letters[1:5], JpnTest=rep("999", 5), stringsAsFactors = F)
sending incremental file list
> ttt
a.exe
  type JpnTest
 
1    a    999
sent 323142 bytes  received 31 bytes  646346.00 bytes/sec
2    b    999
total size is 1198416  speedup is 3.71
3    c     999
 
4    d    999
c:\Rtools\bin>
5    e    999
> jpntest <- function() { ttt$JpnTest[1] ="N5"; print(ttt)}
> jpntest()
  type JpnTest
1    a     N5
2    b    999
3    c    999
4    d    999
5    e    999
> ttt
  type JpnTest
1    a    999
2    b    999
3   c    999
4    d    999
5    e    999
</pre>
</pre>
And rsync works best when we need to sync folder.
<pre>
c:\Rtools\bin>rsync -avz "/cygdrive/c/users/limingc/Downloads/binary" "/cygdrive/c/users/limingc/Documents/"
sending incremental file list
binary/
binary/Eula.txt
binary/cherrytree.lnk
binary/depends64.chm
binary/depends64.dll
binary/depends64.exe
binary/mtputty.exe
binary/procexp.chm
binary/procexp.exe
binary/pscp.exe
binary/putty.exe
binary/sqlite3.exe
binary/wget.exe


sent 4115294 bytes  received 244 bytes  1175868.00 bytes/sec
Example 2. [http://stackoverflow.com/questions/1236620/global-variables-in-r How can we set global variables inside a function?] The answer is to use the "<<-" operator or '''assign(, , envir = .GlobalEnv)''' function.
total size is 8036311  speedup is 1.95


c:\Rtools\bin>rm c:\users\limingc\Documents\binary\procexp.exe
Other resource: [http://adv-r.had.co.nz/Functions.html Advanced R] by Hadley Wickham.
cygwin warning:
  MS-DOS style path detected: c:\users\limingc\Documents\binary\procexp.exe
  Preferred POSIX equivalent is: /cygdrive/c/users/limingc/Documents/binary/procexp.exe
  CYGWIN environment variable option "nodosfilewarning" turns off this warning.
  Consult the user's guide for more details about POSIX paths:
    http://cygwin.com/cygwin-ug-net/using.html#using-pathnames


c:\Rtools\bin>rsync -avz "/cygdrive/c/users/limingc/Downloads/binary" "/cygdrive/c/users/limingc/Documents/"
Example 3. [https://stackoverflow.com/questions/1169534/writing-functions-in-r-keeping-scoping-in-mind Writing functions in R, keeping scoping in mind]
sending incremental file list
binary/
binary/procexp.exe


sent 1767277 bytes  received 35 bytes  3534624.00 bytes/sec
=== New environment ===
total size is 8036311  speedup is 4.55
* http://adv-r.had.co.nz/Environments.html.
* [https://www.r-bloggers.com/2011/06/environments-in-r/ Environments in R]
* load(), attach(), with().
* [https://stackoverflow.com/questions/33109379/how-to-switch-to-a-new-environment-and-stick-into-it How to switch to a new environment and stick into it?] seems not possible!


c:\Rtools\bin>
Run the same function on a bunch of R objects
{{Pre}}
mye = new.env()
load(<filename>, mye)
for(n in names(mye)) n = as_tibble(<nowiki>mye[[n]]</nowiki>)
</pre>
</pre>


Unforunately, if the destination is a network drive, I could get a permission denied (13) error. See also http://superuser.com/questions/69620/rsync-file-permissions-on-windows
Just look at the contents of rda file without saving to anywhere (?load)
 
<pre>
=== Install rgdal package on ubuntu ===
local({
 
  load("myfile.rda")
  ls()
})
</pre>
Or use '''attach()''' which is a wrapper of load(). It creates an environment and slots it into the list right after the global environment, then populates it with the objects we're attaching.
{{Pre}}
attach("all.rda") # safer and will warn about masked objects w/ same name in .GlobalEnv
ls(pos = 2)
##  also typically need to cleanup the search path:
detach("file:all.rda")
</pre>
If we want to read data from internet, '''load()''' works but not attach().
<pre>
<pre>
sudo apt-get install libgdal1-dev libproj-dev
con <- url("http://some.where.net/R/data/example.rda")
R
## print the value to see what objects were created.
> install.packages("rgdal")
print(load(con))
close(con)
# Github example
# https://stackoverflow.com/a/62954840
</pre>
</pre>
 
[https://stackoverflow.com/a/39621091 source() case].  
=== Set up Emacs on Windows ===
Edit the file ''C:\Program Files\GNU Emacs 23.2\site-lisp\site-start.el'' with something like
<pre>
<pre>
(setq-default inferior-R-program-name
myEnv <- new.env()   
              "c:/program files/r/r-2.15.2/bin/i386/rterm.exe")
source("some_other_script.R", local=myEnv)
attach(myEnv, name="sourced_scripts")
search()
ls(2)
ls(myEnv)
with(myEnv, print(x))
</pre>
</pre>


=== Database ===
=== str( , max) function ===
Use '''max.level''' parameter to avoid a long display of the structure of a complex R object. Use '''give.head = FALSE''' to hide the attributes. See [https://www.rdocumentation.org/packages/utils/versions/3.6.1/topics/str ?str]


==== [http://cran.r-project.org/web/packages/RSQLite/index.html RSQLite] ====
If we use str() on a function like str(lm), it is equivalent to args(lm)
[http://blog.sobbayi.com/sql


==== [https://cran.r-project.org/web/packages/sqldf/ sqldf] ====
For a complicated list object, it is useful to use the '''max.level''' argument; e.g. str(, max.level = 1)
Manipulate R data frames using SQL. Depends on RSQLite. [http://datascienceplus.com/a-use-of-gsub-reshape2-and-sqldf-with-healthcare-data/ A use of gsub, reshape2 and sqldf with healthcare data]


==== [https://cran.r-project.org/web/packages/RPostgreSQL/index.html RPostgreSQL] ====
For a large data frame, we can use the '''tibble()''' function; e.g. mydf %>% tibble()


==== [[MySQL#Use_through_R|RMySQL]] ====
=== tidy() function ===
* http://datascienceplus.com/bringing-the-powers-of-sql-into-r/
broom::tidy() provides a simplified form of an R object (obtained from running some analysis). See [[Tidyverse#broom|here]].


==== MongoDB ====
=== View all objects present in a package, ls() ===
* http://www.r-bloggers.com/r-and-mongodb/
https://stackoverflow.com/a/30392688. In the case of an R package created by Rcpp.package.skeleton("mypackage"), we will get
* http://watson.nci.nih.gov/~sdavis/blog/rmongodb-using-R-with-mongo/
{{Pre}}
> devtools::load_all("mypackage")
> search()
[1] ".GlobalEnv"        "devtools_shims"    "package:mypackage"
[4] "package:stats"    "package:graphics"  "package:grDevices"
[7] "package:utils"    "package:datasets"  "package:methods"
[10] "Autoloads"        "package:base"


=== Github ===
> ls("package:mypackage")
 
[1] "_mypackage_rcpp_hello_world" "evalCpp"                    "library.dynam.unload"     
==== R source  ====
[4] "rcpp_hello_world"            "system.file"
https://github.com/wch/r-source/ Daily update, interesting, should be visited every day. Clicking '''1000+ commits''' to look at daily changes.
</pre>


If we are interested in a certain branch (say 3.2), look for R-3-2-branch.
Note that the first argument of ls() (or detach()) is used to specify the environment. It can be
* an integer (the position in the ‘search’ list);
* the character string name of an element in the search list;
* an explicit ‘environment’ (including using ‘sys.frame’ to access the currently active function calls).


==== R packages (only) source (metacran) ====
== Speedup R code ==
* https://github.com/cran/ by [https://github.com/gaborcsardi Gábor Csárdi], the author of '''[http://igraph.org/ igraph]''' software.
* [http://datascienceplus.com/strategies-to-speedup-r-code/ Strategies to speedup R code] from DataScience+


==== Bioconductor packages source ====
=== Profiler ===
* [https://stat.ethz.ch/pipermail/bioc-devel/2015-June/007675.html Announcement]
* [https://www.rstudio.com/resources/videos/understand-code-performance-with-the-profiler/ Understand Code Performance with the profiler] (Video)
* https://github.com/Bioconductor-mirror
* [https://github.com/atheriel/xrprof-package xrprof] package, [https://www.infoworld.com/article/3604688/top-r-tips-and-news-from-rstudio-global-2021.amp.html Top R tips and news from RStudio Global 2021]


==== Send local repository to Github in R by using reports package ====
== && vs & ==
http://www.youtube.com/watch?v=WdOI_-aZV0Y
See https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/Logic.  
 
==== My collection ====
* https://github.com/arraytools
* https://gist.github.com/4383351 heatmap using leukemia data
* https://gist.github.com/4382774 heatmap using sequential data
* https://gist.github.com/4484270 biocLite


==== How to download ====
* The shorter form performs elementwise comparisons in much the same way as arithmetic operators. The return is a vector.
* The longer form evaluates left to right examining only the first element of each vector. The return is one value.
* '''The longer form''' evaluates left to right examining only the first element of each vector. '''Evaluation proceeds only until the result is determined.'''
* The idea of the longer form && in R seems to be the same as the && operator in linux shell; see [https://youtu.be/AVXYq8aL47Q?t=1475 here].
* [https://medium.com/biosyntax/single-or-double-and-operator-and-or-operator-in-r-442f00332d5b Single or double?: AND operator and OR operator in R]. The confusion might come from the inconsistency when choosing these operators in different languages. For example, in C, & performs bitwise AND, while && does Boolean logical AND.
* [https://www.tjmahr.com/think-of-stricter-logical-operators/ Think of && as a stricter &]


Clone ~ Download.
* Command line
<pre>
<pre>
git clone https://gist.github.com/4484270.git
c(T,F,T) & c(T,T,T)
# [1]  TRUE FALSE  TRUE
c(T,F,T) && c(T,T,T)
# [1] TRUE
c(T,F,T) && c(F,T,T)
# [1] FALSE
c(T,F,T) && c(NA,T,T)
# [1] NA
</pre>
</pre>
This will create a subdirectory called '4484270' with all cloned files there.
* Within R
<pre>
<pre>
library(devtools)
# Assume 'b' is not defined
source_gist("4484270")
> if (TRUE && b==3) cat("end")
Error: object 'b' not found
> if (FALSE && b==3) cat("end")
> # No error since the 2nd condition is never evaluated
</pre>
</pre>
or
It's useful in functions(). We don't need nested if statements. In this case if 'arg' is missing, the argument 'L' is not needed so there is not syntax error.
First download the json file from
https://api.github.com/users/MYUSERLOGIN/gists
and then
<pre>
<pre>
library(RJSONIO)
> foo <- function(arg, L) {
x <- fromJSON("~/Downloads/gists.json")
  # Suppose 'L' is meaningful only if 'arg' is provided
setwd("~/Downloads/")
  #
gist.id <- lapply(x, "[[", "id")
  # Evaluate 'L' only if 'arg' is provided
lapply(gist.id, function(x){
  #
  cmd <- paste0("git clone https://gist.github.com/", x, ".git")
  if (!missing(arg) && L) {
  system(cmd)
    print("L is true")
})
  } else {
    print("Either arg is missing or L is FALSE")
  }
}
> foo()
[1] "arg is missing or L is FALSE"
> foo("a", F)
[1] "arg is missing or L is FALSE"
> foo("a", T)
[1] "L is true"
</pre>
</pre>
Other examples: '''&&''' is more flexible than '''&'''.
<pre>
nspot <- ifelse(missing(rvm) || !rvm, nrow(exprTrain), sum(filter))


==== Jekyll ====
if (!is.null(exprTest) && any(is.na(exprTest))) { ... }
[http://statistics.rainandrhino.org/2015/12/15/jekyll-r-blogger-knitr-hyde.html An Easy Start with Jekyll, for R-Bloggers]
</pre>


=== Connect R with Arduino ===
== for-loop, control flow ==
* http://lamages.blogspot.com/2012/10/connecting-real-world-to-r-with-arduino.html
* [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/Control ?Control]
* http://jean-robert.github.io/2012/11/11/thermometer-R-using-Arduino-Java.html
* '''next''' can be used to skip the rest of the inner-most loop
* http://bio7.org/?p=2049
* [https://www.programiz.com/r/ifelse-function ifelse() Function]
* http://www.rforge.net/Arduino/svn.html


=== Android App ===
== Vectorization ==
* [https://play.google.com/store/apps/details?id=appinventor.ai_RInstructor.R2&hl=zh_TW R Instructor] $4.84
* [https://en.wikipedia.org/wiki/Vectorization_%28mathematics%29 Vectorization (Mathematics)] from wikipedia
* [http://realxyapp.blogspot.tw/2010/12/statistical-distribution.html Statistical Distribution] (Not R related app)
* [https://en.wikipedia.org/wiki/Array_programming Array programming] from wikipedia
* [https://en.wikipedia.org/wiki/SIMD Single instruction, multiple data (SIMD)] from wikipedia
* [https://stackoverflow.com/a/1422181 What is vectorization] stackoverflow
* http://www.noamross.net/blog/2014/4/16/vectorization-in-r--why.html
* https://github.com/vsbuffalo/devnotes/wiki/R-and-Vectorization
* [https://statcompute.wordpress.com/2018/09/16/why-vectorize/ Why Vectorize?] statcompute.wordpress.com
* [https://www.jimhester.com/2018/04/12/vectorize/ Beware of Vectorize] from Jim Hester
* [https://github.com/henrikbengtsson/matrixstats matrixStats]: Functions that Apply to Rows and Columns of Matrices (and to Vectors). E.g. col / rowMedians(), col / rowRanks(), and col / rowSds(). [https://github.com/HenrikBengtsson/matrixStats/wiki/Benchmark-reports Benchmark reports].


=== Time series stock price plot ===
=== sapply vs vectorization ===
* http://blog.revolutionanalytics.com/2015/08/plotting-time-series-in-r.html (ggplot2, xts, dygraphs)
[http://theautomatic.net/2019/03/13/speed-test-sapply-vs-vectorization/ Speed test: sapply vs vectorization]


=== Circular plot ===
=== lapply vs for loop ===
* http://freakonometrics.hypotheses.org/20667 which uses https://cran.r-project.org/web/packages/circlize/ circlize] package.
* [https://stackoverflow.com/a/42440872 lapply vs for loop - Performance R]
* https://www.biostars.org/p/17728/
* https://code-examples.net/en/q/286e03a
* [https://cran.r-project.org/web/packages/RCircos/ RCircos] package from CRAN.
* [https://johanndejong.wordpress.com/2016/07/07/r-are-apply-loops-faster-than-for-loops/ R: are *apply loops faster than for loops?]
* [http://www.bioconductor.org/packages/release/bioc/html/OmicCircos.html OmicCircos] from Bioconductor.


=== Venn Diagram ===
=== [https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/split split()] and sapply() ===
* limma http://www.ats.ucla.edu/stat/r/faq/venn.htm - only black and white?
split() can be used to split a vector, columns or rows. See [https://stackoverflow.com/questions/3302356/how-to-split-a-data-frame How to split a data frame?]
* VennDiagram - input has to be the numbers instead of the original vector?
<ul>
* http://manuals.bioinformatics.ucr.edu/home/R_BioCondManual#TOC-Venn-Diagrams and the [http://faculty.ucr.edu/~tgirke/Documents/R_BioCond/My_R_Scripts/overLapper.R R code] or the [http://www.bioconductor.org/packages/release/bioc/html/systemPipeR.html Bioc package systemPipeR]
<li>Split divides the data in the '''vector''' or '''data frame''' x into the groups defined by f. The syntax is
<syntaxhighlight lang='rsplus'>
{{Pre}}
# systemPipeR package method
split(x, f, drop = FALSE, )
library(systemPipeR)
</pre>
setlist <- list(A=sample(letters, 18), B=sample(letters, 16), C=sample(letters, 20), D=sample(letters, 22), E=sample(letters, 18))  
OLlist <- overLapper(setlist[1:3], type="vennsets")
vennPlot(list(OLlist))                           


# R script source method
<li>split() + cut(). [https://www.r-bloggers.com/2024/10/how-to-split-data-into-equal-sized-groups-in-r-a-comprehensive-guide-for-beginners/ How to Split Data into Equal Sized Groups in R: A Comprehensive Guide for Beginners]
source("http://faculty.ucr.edu/~tgirke/Documents/R_BioCond/My_R_Scripts/overLapper.R")
<li>[https://stackoverflow.com/a/3321659 Split a vector into chunks]. split() returns a vector/indices and the indices can be used in lapply() to subset the data. Useful for the '''split() + lapply() + do.call()''' or '''split() + sapply()''' operations.
setlist <- list(A=sample(letters, 18), B=sample(letters, 16), C=sample(letters, 20), D=sample(letters, 22), E=sample(letters, 18))  
<pre>
# or (obtained by dput(setlist))
d <- 1:10
setlist <- structure(list(A = c("o", "h", "u", "p", "i", "s", "a", "w",
chunksize <- 4
"b", "z", "n", "c", "k", "j", "y", "m", "t", "q"), B = c("h",
ceiling(1:10/4)
"r", "x", "y", "b", "t", "d", "o", "m", "q", "g", "v", "c", "u",
# [1] 1 1 1 1 2 2 2 2 3 3
"f", "z"), C = c("b", "e", "t", "u", "s", "j", "o", "k", "d",
split(d, ceiling(seq_along(d)/chunksize))
"l", "g", "i", "w", "n", "p", "a", "y", "x", "m", "z"), D = c("f",
# $`1`
"g", "b", "k", "j", "m", "e", "q", "i", "d", "o", "l", "c", "t",
# [1] 1 2 3 4
"x", "r", "s", "u", "w", "a", "z", "n"), E = c("u", "w", "o",
#
"k", "n", "h", "p", "z", "l", "m", "r", "d", "q", "s", "x", "b",
# $`2`
"v", "t"), F = c("o", "j", "r", "c", "l", "l", "u", "b", "f",
# [1] 5 6 7 8
"d", "u", "m", "y", "t", "y", "s", "a", "g", "t", "m", "x", "m"
#
)), .Names = c("A", "B", "C", "D", "E", "F"))
# $`3`
# [1]  9 10
do.call(c, lapply(split(d, ceiling(seq_along(d)/4)), function(x) sum(x)) )  
#  1  2  3
# 10 26 19


OLlist <- overLapper(setlist[1:3], type="vennsets")
# bigmemory vignette
counts <- list(sapply(OLlist$Venn_List, length))
planeindices <- split(1:nrow(x), x[,'TailNum'])
vennPlot(counts=counts)                          
planeStart <- sapply(planeindices,
</syntaxhighlight>
                    function(i) birthmonth(x[i, c('Year','Month'),
                                            drop=FALSE]))
</pre>


[[File:Vennplot.png|250px]]
<li>Split rows of a data frame/matrix; e.g. rows represents genes. The data frame/matrix is split directly.
{{Pre}}
split(mtcars,mtcars$cyl)


=== Amazing plots ===
split(data.frame(matrix(1:20, nr=10) ), ceiling(1:10/chunksize)) # data.frame/tibble works
==== New R logo 2/11/2016 ====
split.data.frame(matrix(1:20, nr=10), ceiling(1:10/chunksize))   # split.data.frame() works for matrices
* http://rud.is/b/2016/02/11/plot-the-new-svg-r-logo-with-ggplot2/
</pre>
* https://www.stat.auckland.ac.nz/~paul/Reports/Rlogo/Rlogo.html
 
<syntaxhighlight lang='rsplus'>
<li>Split columns of a data frame/matrix.  
library(sp)
{{Pre}}
library(maptools)
ma <- cbind(x = 1:10, y = (-4:5)^2, z = 11:20)
library(ggplot2)
split(ma, cbind(rep(1,10), rep(2, 10), rep(1,10))) # not an interesting example
library(ggthemes)
# $`1`
# rgeos requires the installation of GEOS from http://trac.osgeo.org/geos/
# [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20
system("curl http://download.osgeo.org/geos/geos-3.5.0.tar.bz2 | tar jx")
#
system("cd geos-3.5.0; ./configure; make; sudo make install")
# $`2`
library(rgeos)
#  [1] 16  9  4  1  0  1  4  9 16 25
</pre>
r_wkt_gist_file <- "https://gist.githubusercontent.com/hrbrmstr/07d0ccf14c2ff109f55a/raw/db274a39b8f024468f8550d7aeaabb83c576f7ef/rlogo.wkt"
if (!file.exists("rlogo.wkt")) download.file(r_wkt_gist_file, "rlogo.wkt")
rlogo <- readWKT(paste0(readLines("rlogo.wkt", warn=FALSE))) # rgeos
rlogo_shp <- SpatialPolygonsDataFrame(rlogo, data.frame(poly=c("halo", "r"))) # sp
rlogo_poly <- fortify(rlogo_shp, region="poly") # ggplot2
ggplot(rlogo_poly) +
  geom_polygon(aes(x=long, y=lat, group=id, fill=id)) +
  scale_fill_manual(values=c(halo="#b8babf", r="#1e63b5")) +
  coord_equal() +
  theme_map() +
  theme(legend.position="none")
</syntaxhighlight>


==== 3D plot ====
<li>split() + sapply() to merge columns. See below [[#Mean_of_duplicated_columns:_rowMeans.3B_compute_Means_by_each_row|Mean of duplicated columns]] for more detail.  
Using [https://chitchatr.wordpress.com/2010/06/28/fun-with-persp-function/ persp] function to create the following plot.


[[File:3dpersp.png|200px]]
<li>split() + sapply() to split a vector. See [https://www.rdocumentation.org/packages/genefilter/versions/1.54.2/topics/nsFilter nsFilter()] function which can remove duplicated probesets/rows using unique Entrez Gene IDs ('''genefilter''' package). The source code of [https://github.com/Bioconductor/genefilter/blob/b86f2cf47cf420b1444188bfe970714a7cc7f33b/R/nsFilter.R#L224 nsFilter()] and [https://github.com/Bioconductor/genefilter/blob/b86f2cf47cf420b1444188bfe970714a7cc7f33b/R/all.R#L170 findLargest()].  
<syntaxhighlight lang='rsplus'>
{{Pre}}
### Random pattern
tSsp = split.default(testStat, lls)  
# Create matrix with random values with dimension of final grid
# testStat is a vector of numerics including probeset IDs as names
  rand <- rnorm(441, mean=0.3, sd=0.1)
# lls is a vector of entrez IDs (same length as testStat)
  mat.rand <- matrix(rand, nrow=21)
# tSSp is a list of the same length as unique elements of lls.
# Create another matrix for the colors. Start by making all cells green
  fill <- matrix("green3", nr = 21, nc = 21)  
# Change colors in each cell based on corresponding mat.rand value
  fcol <- fill
  fcol[] <- terrain.colors(40)[cut(mat.rand,
    stats::quantile(mat.rand, seq(0,1, len = 41),
    na.rm=T), include.lowest = TRUE)]
# Create concave surface using expontential function
  x <- -10:10
  y <- x^2
  y <- as.matrix(y)
  y1 <- y
  for(i in 1:20){tmp <- cbind(y,y1); y1 <- tmp[,1]; y <- tmp;}
  mat <- tmp[1:21, 1:21]
# Plot it up!
  persp(1:21, 1:21, t(mat)/10, theta = 90, phi = 35,col=fcol,
    scale = FALSE, axes = FALSE, box = FALSE)


### Organized pattern
sapply(tSsp, function(x) names(which.max(x)))  
# Same as before
# return a vector of probset IDs of length of unique entrez IDs
  rand <- rnorm(441, mean=0.3, sd=0.1)
</pre>
</ul>
# Create concave surface using expontential function
  x <- -10:10
  y <- x^2
  y <- as.matrix(y)
  for(i in 1:20){tmp <- cbind(y,y); y1 <- tmp[,1]; y <- tmp;}
  mat <- tmp[1:21, 1:21]
###Organize rand by y and put into matrix form
  o <- order(rand,as.vector(mat))
  o.tmp <- cbind(rand[o], rev(sort(as.vector(mat))))
  mat.org <- matrix(o.tmp[,1], nrow=21)
  half.1 <- mat.org[,seq(1,21,2)]
  half.2 <- mat.org[,rev(seq(2,20,2))]
  full <- cbind(half.1, half.2)
  full <- t(full)
# Again, create color matrix and populate using rand values
zi <- full[-1, -1] + full[-1, -21] + full[-21,-1] + full[-21, -21]
fill <- matrix("green3", nr = 20, nc = 20)
fcol <- fill
fcol[] <- terrain.colors(40)[cut(zi,
        stats::quantile(zi, seq(0,1, len = 41), na.rm=T),
        include.lowest = TRUE)]
# Plot it up!       
persp(1:21, 1:21, t(mat)/10, theta = 90, phi = 35,col=t(fcol),
    scale = FALSE, axes = FALSE, box = FALSE)
</syntaxhighlight>


==== Christmas tree ====
=== strsplit and sapply ===
http://wiekvoet.blogspot.com/2014/12/merry-christmas.html
{{Pre}}
<syntaxhighlight lang='rsplus'>
> namedf <- c("John ABC", "Mary CDE", "Kat FGH")
# http://blogs.sas.com/content/iml/2012/12/14/a-fractal-christmas-tree/
> strsplit(namedf, " ")
# Each row is a 2x2 linear transformation
[[1]]
# Christmas tree
[1] "John" "ABC"
L <- matrix(
    c(0.03,  0,    0  ,  0.1,
        0.85,  0.00,  0.00, 0.85,
        0.8,  0.00,  0.00, 0.8,
        0.2,  -0.08,  0.15, 0.22,
        -0.2,   0.08, 0.15, 0.22,
        0.25, -0.1,  0.12, 0.25,
        -0.2,  0.1,  0.12, 0.2),
    nrow=4)
# ... and each row is a translation vector
B <- matrix(
    c(0, 0,
        0, 1.5,
        0, 1.5,
        0, 0.85,
        0, 0.85,
        0, 0.3,
        0, 0.4),
    nrow=2)


prob = c(0.02, 0.6,.08, 0.07, 0.07, 0.07, 0.07)
[[2]]
[1] "Mary" "CDE"


# Iterate the discrete stochastic map
[[3]]
N = 1e5 #5  #  number of iterations
[1] "Kat" "FGH"
x = matrix(NA,nrow=2,ncol=N)
x[,1] = c(0,2)  # initial point
k <- sample(1:7,N,prob,replace=TRUE) # values 1-7


for (i in 2:N)  
> sapply(strsplit(namedf, " "), "[", 1)
  x[,i] = crossprod(matrix(L[,k[i]],nrow=2),x[,i-1]) + B[,k[i]] # iterate
[1] "John" "Mary" "Kat"
> sapply(strsplit(namedf, " "), "[", 2)
[1] "ABC" "CDE" "FGH"
</pre>


# Plot the iteration history
=== Mean of duplicated columns: rowMeans; compute Means by each row ===
png('card.png')
<ul>
par(bg='darkblue',mar=rep(0,4))  
<li>[https://stackoverflow.com/questions/35925529/reduce-columns-of-a-matrix-by-a-function-in-r Reduce columns of a matrix by a function in R]. To use rowMedians() instead of rowMeans(), we need to install [https://cran.r-project.org/web/packages/matrixStats/index.html matrixStats] from CRAN.
plot(x=x[1,],y=x[2,],
<syntaxhighlight lang='r'>
    col=grep('green',colors(),value=TRUE),
set.seed(1)
    axes=FALSE,
x <- matrix(1:60, nr=10); x[1, 2:3] <- NA
    cex=.1,
colnames(x) <- c("b", "b", "b", "c", "a", "a"); x
    xlab='',
res <- sapply(split(1:ncol(x), colnames(x)),
    ylab='' )#,pch='.')
              function(i) rowMeans(x[, i, drop=F], na.rm = TRUE))
res  # notice the sorting of columns
      a  b  c
[1,] 46  1 31
[2,] 47 12 32
[3,] 48 13 33
[4,] 49 14 34
[5,] 50 15 35
[6,] 51 16 36
[7,] 52 17 37
[8,] 53 18 38
[9,] 54 19 39
[10,] 55 20 40


bals <- sample(N,20)
# vapply() is safter than sapply().  
points(x=x[1,bals],y=x[2,bals]-.1,
# The 3rd arg in vapply() is a template of the return value.
    col=c('red','blue','yellow','orange'),
res2 <- vapply(split(1:ncol(x), colnames(x)),  
    cex=2,
              function(i) rowMeans(x[, i, drop=F], na.rm = TRUE),
    pch=19
              rep(0, nrow(x)))
)
text(x=-.7,y=8,
    labels='Merry',
    adj=c(.5,.5),
    srt=45,
    vfont=c('script','plain'),
    cex=3,
    col='gold'
)
text(x=0.7,y=8,
    labels='Christmas',
    adj=c(.5,.5),
    srt=-45,
    vfont=c('script','plain'),
    cex=3,
    col='gold'
)
</syntaxhighlight>
</syntaxhighlight>
[[File:XMastree.png|150px]]
</li>
<li>[https://www.rdocumentation.org/packages/base/versions/3.5.2/topics/colSums colSums, rowSums, colMeans, rowMeans] (no group variable). These functions are equivalent to use of ‘apply’ with ‘FUN = mean’ or ‘FUN = sum’ with appropriate margins, but are a lot faster.
{{Pre}}
rowMeans(x, na.rm=T)
# [1] 31 27 28 29 30 31 32 33 34 35


==== Happy Thanksgiving ====
apply(x, 1, mean, na.rm=T)
[http://blog.revolutionanalytics.com/2015/11/happy-thanksgiving.html Turkey]
# [1] 31 27 28 29 30 31 32 33 34 35
</pre>
</li>
<li>[https://cran.r-project.org/web/packages/matrixStats/index.html matrixStats]: Functions that Apply to Rows and Columns of Matrices (and to Vectors)
</li>
<li>[https://www.statforbiology.com/2020/stat_r_tidyverse_columnwise/ From ''for()'' loops to the ''split-apply-combine'' paradigm for column-wise tasks: the transition for a dinosaur]  
</li>
</ul>


[[File:Turkey.png|150px]]
=== Mean of duplicated rows: colMeans and rowsum ===
<ul>
<li>[https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/colSums colMeans(x, na.rm = FALSE, dims = 1)], take mean per columns & sum over rows. It returns a vector. Other similar idea functions include '''colSums, rowSums, rowMeans'''.
{{Pre}}
x <- matrix(1:60, nr=10); x[1, 2:3] <- NA; x
rownames(x) <- c(rep("b", 2), rep("c", 3), rep("d", 4), "a") # move 'a' to the last
res <- sapply(split(1:nrow(x), rownames(x)),
              function(i) colMeans(x[i, , drop=F], na.rm = TRUE))
res <- t(res) # transpose is needed since sapply() will form the resulting matrix by columns
res  # still a matrix, rows are ordered
#  [,1] [,2] [,3] [,4] [,5] [,6]
# a 10.0 20.0 30.0 40.0 50.0 60.0
# b  1.5 12.0 22.0 31.5 41.5 51.5
# c  4.0 14.0 24.0 34.0 44.0 54.0
# d  7.5 17.5 27.5 37.5 47.5 57.5
table(rownames(x))
# a b c d
# 1 2 3 4


==== treemap ====
aggregate(x, list(rownames(x)), FUN=mean, na.rm = T) # EASY, but it becomes a data frame, rows are ordered
http://ipub.com/treemap/
#  Group.1  V1  V2  V3  V4  V5  V6
# 1      a 10.0 20.0 30.0 40.0 50.0 60.0
# 2      b  1.5 12.0 22.0 31.5 41.5 51.5
# 3      c  4.0 14.0 24.0 34.0 44.0 54.0
# 4      d  7.5 17.5 27.5 37.5 47.5 57.5
</pre>
<li>[[Arraytools#Reducing_multiple_probes.2Fprobe_sets_to_one_per_gene_symbol|Reduce multiple probes by the maximally expressed probe (set) measured by average intensity across arrays]]


[[File:TreemapPop.png|150px]]
</li>
 
<li>[https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/rowsum rowsum(x, group, reorder = TRUE, …)]. Sum over rows. It returns a matrix. This is very special. It's not the same as rowSums. There is no "colsum" function. ''It has the speed advantage over sapply+colSums OR aggregate.''
==== [https://en.wikipedia.org/wiki/Voronoi_diagram Voronoi diagram] ====
{{Pre}}
* https://www.stat.auckland.ac.nz/~paul/Reports/VoronoiTreemap/voronoiTreeMap.html
group <- rownames(x)
* http://letstalkdata.com/2014/05/creating-voronoi-diagrams-with-ggplot/
rowsum(x, group, na.rm=T)/as.vector(table(group))
 
#  [,1] [,2] [,3] [,4] [,5] [,6]
==== Silent Night ====
# a 10.0 20.0 30.0 40.0 50.0 60.0
[[File:Silentnight.png|200px]]
# b  1.5  6.0 11.0 31.5 41.5 51.5
 
# c  4.0 14.0 24.0 34.0 44.0 54.0
<syntaxhighlight lang='rsplus'>
# d  7.5 17.5 27.5 37.5 47.5 57.5
# https://aschinchon.wordpress.com/2014/03/13/the-lonely-acacia-is-rocked-by-the-wind-of-the-african-night/
</pre>
depth <- 9
</li>
angle<-30 #Between branches division
</ul>
L <- 0.90 #Decreasing rate of branches by depth
* [https://stackoverflow.com/questions/25198442/how-to-calculate-mean-median-per-group-in-a-dataframe-in-r How to calculate mean/median per group in a dataframe in r] where '''doBy''' and '''dplyr''' are recommended.
nstars <- 300 #Number of stars to draw
* [https://cran.r-project.org/web/packages/matrixStats/index.html matrixStats]: Functions that Apply to Rows and Columns of Matrices (and to Vectors)
mstars <- matrix(runif(2*nstars), ncol=2)
* [https://cran.r-project.org/web/packages/doBy/ doBy] package
branches <- rbind(c(1,0,0,abs(jitter(0)),1,jitter(5, amount = 5)), data.frame())
* [http://stackoverflow.com/questions/7881660/finding-the-mean-of-all-duplicates use ave() and unique()]
colnames(branches) <- c("depth", "x1", "y1", "x2", "y2", "inertia")
* [http://stackoverflow.com/questions/17383635/average-between-duplicated-rows-in-r data.table package]
for(i in 1:depth)
* [http://stackoverflow.com/questions/10180132/consolidate-duplicate-rows plyr package]
{
<ul>
   df <- branches[branches$depth==i,]
<li>'''by()''' function. [https://thomasadventure.blog/posts/calculating-change-from-baseline-in-r/ Calculating change from baseline in R]
   for(j in 1:nrow(df))
</li>
   {
<li>See [https://finnstats.com/index.php/2021/06/20/aggregate-function-in-r/ '''aggregate''' Function in R- A powerful tool for data frames] & [https://finnstats.com/index.php/2021/06/01/summarize-in-r-data-summarization-in-r/ summarize in r, Data Summarization In R] </li>
    branches <- rbind(branches, c(df[j,1]+1, df[j,4], df[j,5], df[j,4]+L^(2*i+1)*sin(pi*(df[j,6]+angle)/180), df[j,5]+L^(2*i+1)*cos(pi*(df[j,6]+angle)/180), df[j,6]+angle+jitter(10, amount = 8)))
<li>[http://www.statmethods.net/management/aggregate.html aggregate()] function. Too slow! http://slowkow.com/2015/01/28/data-table-aggregate/. [http://www.win-vector.com/blog/2015/10/dont-use-statsaggregate/ Don't use aggregate] post.  
    branches <- rbind(branches, c(df[j,1]+1, df[j,4], df[j,5], df[j,4]+L^(2*i+1)*sin(pi*(df[j,6]-angle)/180), df[j,5]+L^(2*i+1)*cos(pi*(df[j,6]-angle)/180), df[j,6]-angle+jitter(10, amount = 8)))
{{Pre}}
   }
> attach(mtcars)
}
dim(mtcars)
nodes <- rbind(as.matrix(branches[,2:3]), as.matrix(branches[,4:5]))
[1] 32 11
png("image.png", width = 1200, height = 600)
> head(mtcars)
plot.new()
                  mpg cyl disp  hp drat    wt  qsec vs am gear carb
par(mai = rep(0, 4), bg = "gray12")
Mazda RX4        21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
plot(nodes, type="n", xlim=c(-7, 3), ylim=c(0, 5))
Mazda RX4 Wag    21.0   6  160 110 3.90 2.875 17.02  0  1   4    4
for (i in 1:nrow(mstars))
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1   4    1
{
Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
   points(x=10*mstars[i,1]-7, y=5*mstars[i,2], col = "blue4", cex=.7, pch=16)
Hornet Sportabout 18.7  8  360 175 3.15 3.440 17.02  0  0    3    2
   points(x=10*mstars[i,1]-7, y=5*mstars[i,2], col = "blue",  cex=.3, pch=16)
Valiant          18.1   6 225 105 2.76 3.460 20.22  1  0    3    1
   points(x=10*mstars[i,1]-7, y=5*mstars[i,2], col = "white", cex=.1, pch=16)
> with(mtcars, table(cyl, vs))
}
  vs
# The moon
cyl  0  1
points(x=-5, y=3.5, cex=40, pch=16, col="lightyellow")
  4 1 10
# The tree
   6  3  4
for (i in 1:nrow(branches)) {lines(x=branches[i,c(2,4)], y=branches[i,c(3,5)], col = paste("gray", as.character(sample(seq(from=50, to=round(50+5*branches[i,1]), by=1), 1)), sep = ""), lwd=(65/(1+3*branches[i,1])))}
  8 14  0
rm(branches)
> aggdata <-aggregate(mtcars, by=list(cyl,vs), FUN=mean, na.rm=TRUE)
dev.off()
> print(aggdata)
</syntaxhighlight>
  Group.1 Group.2      mpg cyl  disp      hp    drat      wt    qsec vs
1      4      0 26.00000  4 120.30  91.0000 4.430000 2.140000 16.70000  0
2      6      0 20.56667   6 155.00 131.6667 3.806667 2.755000 16.32667  0
3      8      0 15.10000   8 353.10 209.2143 3.229286 3.999214 16.77214  0
4      4      1 26.73000   4 103.62  81.8000 4.035000 2.300300 19.38100  1
5       6      1 19.12500  6 204.55 115.2500 3.420000 3.388750 19.21500  1
        am    gear    carb
1 1.0000000 5.000000 2.000000
2 1.0000000 4.333333 4.666667
3 0.1428571 3.285714 3.500000
4 0.7000000 4.000000 1.500000
5 0.0000000 3.500000 2.500000
> detach(mtcars)


=== Google Analytics ===
# Another example: select rows with a minimum value from a certain column (yval in this case)
==== GAR package ====
> mydf <- read.table(header=T, text='
http://www.analyticsforfun.com/2015/10/query-your-google-analytics-data-with.html
id xval yval
A 1  1
A -2  2
B 3  3
B 4  4
C 5  5
')
> x = mydf$xval
> y = mydf$yval
> aggregate(mydf[, c(2,3)], by=list(id=mydf$id), FUN=function(x) x[which.min(y)])
  id xval yval
1  A    1    1
2  B    3    3
3  C    5    5
</pre>
</li>
</ul>


=== Linear Programming ===
=== Mean by Group ===
http://www.r-bloggers.com/modeling-and-solving-linear-programming-with-r-free-book/
[https://statisticsglobe.com/mean-by-group-in-r Mean by Group in R (2 Examples) | dplyr Package vs. Base R]
 
<pre>
=== Read rrd file ===
aggregate(x = iris$Sepal.Length,                # Specify data column
* https://en.wikipedia.org/wiki/RRDtool
          by = list(iris$Species),              # Specify group indicator
* http://oss.oetiker.ch/rrdtool/
          FUN = mean)                          # Specify function (i.e. mean)
* https://github.com/pldimitrov/Rrd
</pre>
* http://plamendimitrov.net/blog/2014/08/09/r-package-for-working-with-rrd-files/
<pre>
library(dplyr)
iris %>%                                        # Specify data frame
  group_by(Species) %>%                        # Specify group indicator
  summarise_at(vars(Sepal.Length),              # Specify column
              list(name = mean))              # Specify function
</pre>
* [https://www.rdocumentation.org/packages/stats/versions/3.6.2/topics/ave ave(x, ..., FUN)],
* aggregate(x, by, FUN),
* by(x, INDICES, FUN): return is a list
* tapply(): return results as a matrix or array. Useful for [https://en.wikipedia.org/wiki/Jagged_array ragged array].
 
== Apply family ==
Vectorize, aggregate, apply, by, eapply, lapply, mapply, rapply, replicate, scale, sapply, split, tapply, and vapply.
 
The following list gives a hierarchical relationship among these functions.
* '''apply'''(X, MARGIN, FUN, ...) – Apply a Functions Over Array Margins
* '''lapply'''(X, FUN, ...) – Apply a Function over a List (including a data frame) or Vector X.
** '''sapply'''(X, FUN, ..., simplify = TRUE, USE.NAMES = TRUE) – Apply a Function over a List or Vector
*** '''replicate'''(n, expr, simplify = "array")
** '''mapply'''(FUN, ..., MoreArgs = NULL, SIMPLIFY = TRUE, USE.NAMES = TRUE) – Multivariate version of sapply
*** '''Vectorize'''(FUN, vectorize.args = arg.names, SIMPLIFY = TRUE, USE.NAMES = TRUE) - Vectorize a Scalar Function
*** '''Map'''(FUN, ...) A wrapper to mapply with SIMPLIFY = FALSE, so it is guaranteed to return a list.
** '''vapply'''(X, FUN, FUN.VALUE, ..., USE.NAMES = TRUE) – similar to sapply, but has a pre-specified type of return value
** '''rapply'''(object, f, classes = "ANY", deflt = NULL, how = c("unlist", "replace", "list"), ...) – A recursive version of lapply
* '''tapply'''(V, INDEX, FUN = NULL, ..., default = NA, simplify = TRUE) – Apply a Function Over a [https://en.wikipedia.org/wiki/Jagged_array "Ragged" Array]. V is typically a vector where split() will be applied. INDEX is a list of one or more factors.
** '''aggregate'''(D, by, FUN, ..., simplify = TRUE, drop = TRUE) - Apply a function to each '''columns''' of subset data frame split by factors. FUN (such as mean(), weighted.mean(), sum()) is a simple function applied to a vector. D is typically a data frame. This is used to '''summarize''' data.
** '''by'''(D, INDICES, FUN, ..., simplify = TRUE) - Apply a Function to each '''subset data frame''' split by factors. FUN (such as summary(), lm()) is applied to a data frame. D is typically a data frame.
* '''eapply'''(env, FUN, ..., all.names = FALSE, USE.NAMES = TRUE) – Apply a Function over values in an environment
 
[https://www.queryhome.com/tech/76799/r-difference-between-apply-vs-sapply-vs-lapply-vs-tapply Difference between apply vs sapply vs lapply vs tapply?]
* apply - When you want to apply a function to the rows or columns or both of a matrix and output is a one-dimensional if only row or column is selected else it is a 2D-matrix
* lapply - When you want to apply a function to each element of a list in turn and get a list back.
* sapply - When you want to apply a function to each element of a list in turn, but you want a vector back, rather than a list.
* tapply - When you want to apply a function to subsets of a vector and the subsets are defined by some other vector, usually a factor.


=== Amazon Alexa ===
Some short examples:
* http://blagrants.blogspot.com/2016/02/theres-party-at-alexas-place.html
* [http://people.stern.nyu.edu/ylin/r_apply_family.html stern.nyu.edu].  
* [http://www.datasciencemadesimple.com/apply-function-r/ Apply Function in R – apply vs lapply vs sapply vs mapply vs tapply vs rapply vs vapply] from datasciencemadesimple.com.
* [https://stackoverflow.com/a/7141669 How to use which one (apply family) when?]


== Tricks ==
=== Apply vs for loop ===
Note that, apply's performance is not always better than a for loop. See
* http://tolstoy.newcastle.edu.au/R/help/06/05/27255.html (answered by Brian Ripley)
* https://stat.ethz.ch/pipermail/r-help/2014-October/422455.html (has one example)
* [https://johanndejong.wordpress.com/2016/07/07/r-are-apply-loops-faster-than-for-loops/ R: are *apply loops faster than for loops?]. The author said '' 'an important reason for using *apply() functions may instead be that they fit the functional programming paradigm better, where everything is done using function calls and side effects are reduced'... The scope of the variables defined within f is limited to f, and variables defined outside f cannot be modified inside f (except using the special scoping assignment operator <<-).  ''
** [http://adv-r.had.co.nz/Functional-programming.html Functional programming]
* [https://privefl.github.io/blog/why-loops-are-slow-in-r/ Why loops are slow in R]
* [https://stackoverflow.com/a/18763102 Why is `unlist(lapply)` faster than `sapply`?]


=== Getting help ===
=== Progress bar ===
* http://stackoverflow.com/questions/tagged/r
[http://peter.solymos.org/code/2016/09/11/what-is-the-cost-of-a-progress-bar-in-r.html What is the cost of a progress bar in R?]
* https://stat.ethz.ch/pipermail/r-help/
* https://stat.ethz.ch/pipermail/r-devel/


=== Better Coder ===
The package 'pbapply' creates a text-mode progress bar - it works on any platforms. On Windows platform, check out [http://www.theanalystatlarge.com/for-loop-tracking-windows-progress-bar/ this post]. It uses  winProgressBar() and setWinProgressBar() functions.
* http://www.mango-solutions.com/wp/2015/10/10-top-tips-for-becoming-a-better-coder/


=== Change default R repository ===
[https://www.jottr.org/2020/07/04/progressr-erum2020-slides/ e-Rum 2020 Slides on Progressr] by Henrik Bengtsson. [https://www.jottr.org/2021/06/11/progressr-0.8.0/ progressr 0.8.0: RStudio's progress bar, Shiny progress updates, and absolute progress], [https://www.r-bloggers.com/2022/06/progressr-0-10-1-plyr-now-supports-progress-updates-also-in-parallel/ progressr 0.10.1: Plyr Now Supports Progress Updates also in Parallel]
Edit global Rprofile file. On *NIX platforms, it's located in /usr/lib/R/library/base/R/Rprofile although local .Rprofile settings take precedence.


For example, I can specify the R mirror I like by creating a single line <.Rprofile> file under my home directory.
=== simplify option in sapply() ===
<pre>
<pre>
options(repos = "http://cran.rstudio.com/")
library(KEGGREST)
 
names1 <- keggGet(c("hsa05340", "hsa05410"))
names2 <- sapply(names1, function(x) x$GENE)
length(names2)  # same if we use lapply() above
# [1] 2
 
names3 <- keggGet(c("hsa05340"))
names4 <- sapply(names3, function(x) x$GENE)
length(names4)  # may or may not be what we expect
# [1] 76
names4 <- sapply(names3, function(x) x$GENE, simplify = FALSE)
length(names4)  # same if we use lapply() w/o simplify
# [1] 1
</pre>
</pre>


=== Change the default web browser ===
=== lapply and its friends Map(), Reduce(), Filter() from the base package for manipulating lists ===
When I run help.start() function in LXLE, it cannot find its default web browser (seamonkey).
* Examples of using lapply() + split() on a data frame. See [http://rollingyours.wordpress.com/category/r-programming-apply-lapply-tapply/ rollingyours.wordpress.com].
<syntaxhighlight lang='rsplus'>
<ul>
> help.start()
<li>mapply() [https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/mapply documentation]. [https://stackoverflow.com/questions/9519543/merge-two-lists-in-r Use mapply() to merge lists].
If the browser launched by 'xdg-open' is already running, it is *not*
<pre>
    restarted, and you must switch to its window.
mapply(rep, 1:4, 4:1)
Otherwise, be patient ...
mapply(rep, times = 1:4, x = 4:1)
> /usr/bin/xdg-open: 461: /usr/bin/xdg-open: x-www-browser: not found
mapply(function(x, y) seq_len(x) + y,
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: firefox: not found
      c(a =  1, b = 2, c = 3),  # names from first
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: mozilla: not found
      c(A = 10, B = 0, C = -10))
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: epiphany: not found
mapply(c, firstList, secondList, SIMPLIFY=FALSE)
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: konqueror: not found
</pre>
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: chromium-browser: not found
</li>
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: google-chrome: not found
<li>[https://bensstats.wordpress.com/2020/10/06/robservations-3-finding-the-expected-value-of-the-maximum-of-two-bivariate-normal-variables-with-simulation/ Finding the Expected value of the maximum of two Bivariate Normal variables with simulation] sapply + mapply.
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: links2: not found
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: links: not found
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: lynx: not found
/usr/bin/xdg-open: 461: /usr/bin/xdg-open: w3m: not found
xdg-open: no method available for opening 'http://127.0.0.1:27919/doc/html/index.html'
</syntaxhighlight>
 
The solution is to put
<pre>
<pre>
options(browser='seamonkey')
z <- mapply(function(u, v) { max(u, v) },
            u = x[, 1], v = x[, 2])
</pre>
</pre>
in the '''.Rprofile''' of your home directory. If the browser is not in the global PATH, we need to put the full path above.
</li>
<li>[http://www.brodrigues.co/functional_programming_and_unit_testing_for_data_munging/fprog.html Map() and Reduce()] in functional programming </li>
<li>Map(), Reduce(), and Filter() from [http://adv-r.had.co.nz/Functionals.html#functionals-fp Advanced R] by Hadley
<ul>
<li>If you have two or more lists (or data frames) that you need to process in <span style="color: red">parallel</span>, use '''Map()'''. One good example is to compute the weighted.mean() function that requires two input objects. Map() is similar to '''mapply()''' function and is more concise than '''lapply()'''. [http://adv-r.had.co.nz/Functionals.html#functionals-loop Advanced R] has a comment that Map() is better than mapply().
{{Pre}}
# Syntax: Map(f, ...)
 
xs <- replicate(5, runif(10), simplify = FALSE)
ws <- replicate(5, rpois(10, 5) + 1, simplify = FALSE)
Map(weighted.mean, xs, ws)


For one-time only purpose, we can use the ''browser'' option in help.start() function:
# instead of a more clumsy way
<syntaxhighlight lang='rsplus'>
lapply(seq_along(xs), function(i) {
> help.start(browser="seamonkey")
  weighted.mean(xs[[i]], ws[[i]])
If the browser launched by 'seamonkey' is already running, it is *not*
})
    restarted, and you must switch to its window.
</pre>
Otherwise, be patient ...
</li>
</syntaxhighlight>
<li>Reduce() reduces a vector, x, to a single value by <span style="color: red">recursively</span> calling a function, f, two arguments at a time. A good example of using '''Reduce()''' function is to read a list of matrix files and merge them. See [https://stackoverflow.com/questions/29820029/how-to-combine-multiple-matrix-frames-into-one-using-r How to combine multiple matrix frames into one using R?]
{{Pre}}
# Syntax: Reduce(f, x, ...)
 
> m1 <- data.frame(id=letters[1:4], val=1:4)
> m2 <- data.frame(id=letters[2:6], val=2:6)
> merge(m1, m2, "id", all = T)
  id val.x val.y
1  a    1    NA
2  b    2    2
3  c    3    3
4  d    4    4
5  e    NA    5
6  f    NA    6
> m <- list(m1, m2)
> Reduce(function(x,y) merge(x,y, "id",all=T), m)
  id val.x val.y
1  a    1    NA
2  b    2    2
3  c    3    3
4  d    4    4
5  e    NA    5
6  f    NA    6
</pre>
</li>
</ul>
</li>
</ul>
* [https://statcompute.wordpress.com/2018/09/08/playing-map-and-reduce-in-r-subsetting/ Playing Map() and Reduce() in R – Subsetting] - using parallel and future packages. [https://statcompute.wordpress.com/2018/09/22/union-multiple-data-frames-with-different-column-names/ Union Multiple Data.Frames with Different Column Names]
 
=== sapply & vapply ===
* [http://stackoverflow.com/questions/12339650/why-is-vapply-safer-than-sapply This] discusses why '''vapply''' is safer and faster than sapply.
* [http://adv-r.had.co.nz/Functionals.html#functionals-loop Vector output: sapply and vapply] from Advanced R (Hadley Wickham).
* [http://theautomatic.net/2018/11/13/those-other-apply-functions/ THOSE “OTHER” APPLY FUNCTIONS…]. rapply(), vapply() and eapply() are covered.
* [http://theautomatic.net/2019/03/13/speed-test-sapply-vs-vectorization/ Speed test: sapply vs. vectorization]
* sapply can be used in plotting; for example, [https://cran.r-project.org/web/packages/glmnet/vignettes/relax.pdf#page=13 glmnet relax vignette] uses '''sapply(myList, lines, col="grey") ''' to draw multiple lines simultaneously on a list of matrices.


We can work made a change (or create the file) ~/.Renviron or etc/Renviron. See
See parallel::parSapply() for a parallel version of sapply(1:n, function(x)). We can this technique to speed up [https://github.com/SRTRdevhub/C_Statistic_Github/blob/master/Simulation_Demonstration.Rmd#L115 this example].
* [https://stat.ethz.ch/pipermail/r-help/2003-August/037484.html Changing default browser in options()].
* https://stat.ethz.ch/R-manual/R-devel/library/utils/html/browseURL.html


=== Rconsole, Rprofile.site, Renviron.site files ===
=== rapply - recursive version of lapply ===
* https://cran.r-project.org/doc/manuals/r-release/R-admin.html ('''Rprofile.site''')
* http://4dpiecharts.com/tag/recursive/
* https://cran.r-project.org/doc/manuals/r-release/R-intro.html ('''Rprofile.site, Renviron.site, Rconsole''' (Windows only))
* [https://github.com/wch/r-source/search?utf8=%E2%9C%93&q=rapply Search in R source code]. Mainly [https://github.com/wch/r-source/blob/trunk/src/library/stats/R/dendrogram.R r-source/src/library/stats/R/dendrogram.R].
* https://cran.r-project.org/doc/manuals/r-release/R-exts.html  ('''Renviron.site''')
* [http://blog.revolutionanalytics.com/2015/11/how-to-store-and-use-authentication-details-with-r.html How to store and use webservice keys and authentication details]
* [http://itsalocke.com/use-rprofile-give-important-notifications/ Use your .Rprofile to give you important notifications]


If we like to install R packages to a personal directory, follow [https://stat.ethz.ch/pipermail/r-devel/2015-July/071562.html this]. Just add the line
=== replicate ===
<pre>
https://www.datacamp.com/community/tutorials/tutorial-on-loops-in-r
R_LIBS_SITE=F:/R/library
{{Pre}}
> replicate(5, rnorm(3))
          [,1]      [,2]      [,3]      [,4]        [,5]
[1,]  0.2509130 -0.3526600 -0.3170790  1.064816 -0.53708856
[2,] 0.5222548  1.5343319  0.6120194 -1.811913 -1.09352459
[3,] -1.9905533 -0.8902026 -0.5489822  1.308273  0.08773477
</pre>
</pre>
to the file '''R_HOME/etc/x64/Renviron.site'''.


Note that on Windows OS, R/etc contains
See [[#parallel_package|parSapply()]] for a parallel version of replicate().
<pre>
$ ls -l /c/Progra~1/r/r-3.2.0/etc
total 142
-rw-r--r--    1  Administ    1043 Jun 20  2013 Rcmd_environ
-rw-r--r--    1  Administ    1924 Mar 17  2010 Rconsole
-rw-r--r--    1  Administ      943 Oct  3  2011 Rdevga
-rw-r--r--    1  Administ      589 May 20  2013 Rprofile.site
-rw-r--r--    1  Administ  251894 Jan 17  2015 curl-ca-bundle.crt
drwxr-xr-x    1  Administ        0 Jun  8 10:30 i386
-rw-r--r--    1  Administ    1160 Dec 31  2014 repositories
-rw-r--r--    1  Administ    30188 Mar 17  2010 rgb.txt
drwxr-xr-x    3  Administ        0 Jun  8 10:30 x64


$ ls /c/Progra~1/r/r-3.2.0/etc/i386
=== Vectorize ===
Makeconf
* [https://www.rdocumentation.org/packages/base/versions/3.5.3/topics/Vectorize Vectorize(FUN, vectorize.args = arg.names, SIMPLIFY = TRUE, USE.NAMES = TRUE)]: creates a function wrapper that vectorizes a scalar function. Its value is a list or vector or array. It calls '''mapply()'''.
{{Pre}}
> rep(1:4, 4:1)
[1] 1 1 1 1 2 2 2 3 3 4
> vrep <- Vectorize(rep.int)
> vrep(1:4, 4:1)
[[1]]
[1] 1 1 1 1


$ cat /c/Progra~1/r/r-3.2.0/etc/Rconsole
[[2]]
# Optional parameters for the console and the pager
[1] 2 2 2
# The system-wide copy is in R_HOME/etc.
# A user copy can be installed in `R_USER'.


## Style
[[3]]
# This can be `yes' (for MDI) or `no' (for SDI).
[1] 3 3
  MDI = yes
# MDI = no


# the next two are only relevant for MDI
[[4]]
toolbar = yes
[1] 4
statusbar = no
</pre>
* [http://biolitika.si/vectorizing-functions-in-r-is-easy.html Vectorizing functions in R is easy]
{{Pre}}
> rweibull(1, 1, c(1, 2)) # no error but not sure what it gives?
[1] 2.17123
> Vectorize("rweibull")(n=1, shape = 1, scale = c(1, 2))
[1] 1.6491761 0.9610109
</pre>
* https://blogs.msdn.microsoft.com/gpalem/2013/03/28/make-vectorize-your-friend-in-r/ 
{{Pre}}
myfunc <- function(a, b) a*b
myfunc(1, 2) # 2
myfunc(3, 5) # 15
myfunc(c(1,3), c(2,5)) # 2 15
Vectorize(myfunc)(c(1,3), c(2,5)) # 2 15


## Font.
myfunc2 <- function(a, b) if (length(a) == 1) a * b else NA
# Please use only fixed width font.
myfunc2(1, 2) # 2
# If font=FixedFont the system fixed font is used; in this case
myfunc2(3, 5) # 15
# points and style are ignored. If font begins with "TT ", only
myfunc2(c(1,3), c(2,5)) # NA
# True Type fonts are searched for.
Vectorize(myfunc2)(c(1, 3), c(2, 5)) # 2 15
font = TT Courier New
Vectorize(myfunc2)(c(1, 3, 6), c(2, 5)) # 2 15 12
points = 10
                                        # parameter will be re-used
style = normal # Style can be normal, bold, italic
</pre>


# Dimensions (in characters) of the console.
== plyr and dplyr packages ==
rows = 25
[https://peerj.com/collections/50-practicaldatascistats/ Practical Data Science for Stats - a PeerJ Collection]
columns = 80
# Dimensions (in characters) of the internal pager.
pgrows = 25
pgcolumns = 80
# should options(width=) be set to the console width?
setwidthonresize = yes


# memory limits for the console scrolling buffer, in chars and lines
[http://www.jstatsoft.org/v40/i01/paper The Split-Apply-Combine Strategy for Data Analysis] (plyr package) in J. Stat Software.
# NB: bufbytes is in bytes for R < 2.7.0, chars thereafter.
bufbytes = 250000
buflines = 8000


# Initial position of the console (pixels, relative to the workspace for MDI)
[http://seananderson.ca/courses/12-plyr/plyr_2012.pdf A quick introduction to plyr] with a summary of apply functions in R and compare them with functions in plyr package.
# xconsole = 0
# yconsole = 0


# Dimension of MDI frame in pixels
# plyr has a common syntax -- easier to remember
# Format (w*h+xorg+yorg) or use -ve w and h for offsets from right bottom
# plyr requires less code since it takes care of the input and output format
# This will come up maximized if w==0
# plyr can easily be run in parallel -- faster
# MDIsize = 0*0+0+0
# MDIsize = 1000*800+100+0
# MDIsize = -50*-50+50+50  # 50 pixels space all round


# The internal pager can displays help in a single window
Tutorials
# or in multiple windows (one for each topic)
* [http://dplyr.tidyverse.org/articles/dplyr.html Introduction to dplyr] from http://dplyr.tidyverse.org/.
# pagerstyle can be set to `singlewindow' or `multiplewindows'
* A video of [http://cran.r-project.org/web/packages/dplyr/index.html dplyr] package can be found on [http://vimeo.com/103872918 vimeo].
pagerstyle = multiplewindows
* [http://www.dataschool.io/dplyr-tutorial-for-faster-data-manipulation-in-r/ Hands-on dplyr tutorial for faster data manipulation in R] from dataschool.io.


## Colours for console and pager(s)
Examples of using dplyr:
# (see rwxxxx/etc/rgb.txt for the known colours).
* [http://wiekvoet.blogspot.com/2015/03/medicines-under-evaluation.html Medicines under evaluation]
background = White
* [http://rpubs.com/seandavi/GEOMetadbSurvey2014 CBI GEO Metadata Survey]
normaltext = NavyBlue
* [http://datascienceplus.com/r-for-publication-by-page-piccinini-lesson-3-logistic-regression/ Logistic Regression] by Page Piccinini. mutate(), inner_join() and %>%.
usertext = Red
* [http://rpubs.com/turnersd/plot-deseq-results-multipage-pdf DESeq2 post analysis] select(), gather(), arrange() and %>%.  
highlight = DarkRed


## Initial position of the graphics window
=== [https://cran.r-project.org/web/packages/tibble/ tibble] ===
## (pixels, <0 values from opposite edge)
[https://www.r-bloggers.com/2024/08/tidy-dataframes-but-not-tibbles/ Tidy DataFrames but not Tibbles]
xgraphics = -25
ygraphics = 0


## Language for messages
Tibble objects
language =
* it does not have row names (cf data frame),
* it never changes the type of the inputs (e.g. it never converts strings to factors!),
* it never changes the names of variables


## Default setting for console buffering: 'yes' or 'no'
To show all rows or columns of a tibble object,
buffered = yes
</pre>
and on Linux
<pre>
<pre>
brb@brb-T3500:~$ whereis R
print(tbObj, n= Inf)
R: /usr/bin/R /etc/R /usr/lib/R /usr/bin/X11/R /usr/local/lib/R /usr/share/R /usr/share/man/man1/R.1.gz


brb@brb-T3500:~$ ls /usr/lib/R
print(tbObj, width = Inf)
bin  COPYING  etc  lib  library  modules  site-library  SVN-REVISION
</pre>


brb@brb-T3500:~$ ls /usr/lib/R/etc
If we try to do a match on some column of a tibble object, we will get zero matches. The issue is we cannot use an index to get a tibble column.
javaconf  ldpaths  Makeconf  Renviron  Renviron.orig  Renviron.site  Renviron.ucf  repositories  Rprofile.site


brb@brb-T3500:~$ ls /usr/local/lib/R
'''Subsetting''': to [https://stackoverflow.com/questions/21618423/extract-a-dplyr-tbl-column-as-a-vector extract a column from a tibble object], use '''[[''' or '''$''' or dplyr::pull(). [https://www.datanovia.com/en/lessons/select-data-frame-columns-in-r/ Select Data Frame Columns in R].
site-library
{{Pre}}
</pre>
TibbleObject$VarName
and
# OR
<pre>
TibbleObject[["VarName"]]
brb@brb-T3500:~$ cat /usr/lib/R/etc/Rprofile.site
# OR
##                                              Emacs please make this -*- R -*-
pull(TibbleObject, VarName) # won't be a tibble object anymore
## empty Rprofile.site for R on Debian
##
## Copyright (C) 2008 Dirk Eddelbuettel and GPL'ed
##
## see help(Startup) for documentation on ~/.Rprofile and Rprofile.site


# ## Example of .Rprofile
# For multiple columns, use select()
# options(width=65, digits=5)
dplyr::select(TibbleObject, -c(VarName1, VarName2)) # still a tibble object
# options(show.signif.stars=FALSE)
# OR
# setHook(packageEvent("grDevices", "onLoad"),
dplyr::select(TibbleObject, 2:5) #  
#        function(...) grDevices::ps.options(horizontal=FALSE))
# set.seed(1234)
# .First <- function() cat("\n  Welcome to R!\n\n")
# .Last <- function()  cat("\n  Goodbye!\n\n")
 
# ## Example of Rprofile.site
# local({
#  # add MASS to the default packages, set a CRAN mirror
#  old <- getOption("defaultPackages"); r <- getOption("repos")
#  r["CRAN"] <- "http://my.local.cran"
#  options(defaultPackages = c(old, "MASS"), repos = r)
#})
brb@brb-T3500:~$ cat /usr/lib/R/etc/Renviron.site
##                                              Emacs please make this -*- R -*-
## empty Renviron.site for R on Debian
##
## Copyright (C) 2008 Dirk Eddelbuettel and GPL'ed
##
## see help(Startup) for documentation on ~/.Renviron and Renviron.site
 
# ## Example ~/.Renviron on Unix
# R_LIBS=~/R/library
# PAGER=/usr/local/bin/less
 
# ## Example .Renviron on Windows
# R_LIBS=C:/R/library
# MY_TCLTK="c:/Program Files/Tcl/bin"
 
# ## Example of setting R_DEFAULT_PACKAGES (from R CMD check)
# R_DEFAULT_PACKAGES='utils,grDevices,graphics,stats'
# # this loads the packages in the order given, so they appear on
# # the search path in reverse order.
brb@brb-T3500:~$
</pre>
</pre>


=== R release versions ===
'''Convert a data frame to a tibble''' See [http://www.sthda.com/english/wiki/tibble-data-format-in-r-best-and-modern-way-to-work-with-your-data Tibble Data Format in R: Best and Modern Way to Work with Your Data]
[http://cran.r-project.org/web/packages/rversions/index.html rversions]: Query the main 'R' 'SVN' repository to find the released versions & dates.
 
=== R package managment ===
==== Package related functions from package 'utils' ====
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/available.packages.html available.packages()]; see packageStatus().
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/download.packages.html download.packages()]
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/packageStatus.html packageStatus(), update(), upgrade()]. packageStatus() will return a list with two components:
# inst - a data frame with columns as the matrix returned by '''installed.packages''' plus "Status", a factor with levels c("ok", "upgrade"). Note: the manual does not mention "unavailable" case (but I do get it) in R 3.2.0?
# avail - a data frame with columns as the matrix returned by '''available.packages''' plus "Status", a factor with levels c("installed", "not installed", "unavailable"). Note: I don't get the "unavailable" case in R 3.2.0?
<pre>
<pre>
> x <- packageStatus()
my_data <- as_tibble(iris)
> names(x)
class(my_data)
[1] "inst"  "avail"
> dim(x[['inst']])
[1] 225  17
> x[['inst']][1:3, ]
              Package                            LibPath Version Priority              Depends Imports
acepack      acepack C:/Program Files/R/R-3.1.2/library 1.3-3.3    <NA>                  <NA>    <NA>
adabag        adabag C:/Program Files/R/R-3.1.2/library    4.0    <NA> rpart, mlbench, caret    <NA>
affxparser affxparser C:/Program Files/R/R-3.1.2/library  1.38.0    <NA>          R (>= 2.6.0)    <NA>
          LinkingTo                                                        Suggests Enhances
acepack        <NA>                                                            <NA>    <NA>
adabag          <NA>                                                            <NA>    <NA>
affxparser      <NA> R.oo (>= 1.18.0), R.utils (>= 1.32.4),\nAffymetrixDataTestFiles    <NA>
                      License License_is_FOSS License_restricts_use OS_type MD5sum NeedsCompilation Built
acepack    MIT + file LICENSE            <NA>                  <NA>    <NA>  <NA>              yes 3.1.2
adabag            GPL (>= 2)            <NA>                  <NA>    <NA>  <NA>              no 3.1.2
affxparser        LGPL (>= 2)            <NA>                  <NA>    <NA>  <NA>            <NA> 3.1.1
                Status
acepack            ok
adabag              ok
affxparser unavailable
> dim(x[['avail']])
[1] 6538  18
> x[['avail']][1:3, ]
                Package Version Priority                        Depends        Imports LinkingTo
A3                  A3  0.9.2    <NA> R (>= 2.15.0), xtable, pbapply          <NA>      <NA>
ABCExtremes ABCExtremes    1.0    <NA>      SpatialExtremes, combinat          <NA>      <NA>
ABCanalysis ABCanalysis  1.0.1    <NA>                    R (>= 2.10) Hmisc, plotrix      <NA>
                      Suggests Enhances    License License_is_FOSS License_restricts_use OS_type Archs
A3          randomForest, e1071    <NA> GPL (>= 2)            <NA>                  <NA>    <NA>  <NA>
ABCExtremes                <NA>    <NA>      GPL-2            <NA>                  <NA>    <NA>  <NA>
ABCanalysis                <NA>    <NA>      GPL-3            <NA>                  <NA>    <NA>  <NA>
            MD5sum NeedsCompilation File                                      Repository        Status
A3            <NA>            <NA> <NA> http://cran.rstudio.com/bin/windows/contrib/3.1 not installed
ABCExtremes  <NA>            <NA> <NA> http://cran.rstudio.com/bin/windows/contrib/3.1 not installed
ABCanalysis  <NA>            <NA> <NA> http://cran.rstudio.com/bin/windows/contrib/3.1 not installed
</pre>
</pre>
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/packageDescription.html packageVersion(), packageDescription()]
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/install.packages.html install.packages()], [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/remove.packages.html remove.packages()].
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/installed.packages.html installed.packages()]; see packageStatus().
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/update.packages.html update.packages(), old.packages(), new.packages()]
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/setRepositories.html setRepositories()]
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/contrib.url.html contrib.url()]
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/chooseCRANmirror.html chooseCRANmirror()], [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/chooseBioCmirror.html chooseBioCmirror()]
* [http://stat.ethz.ch/R-manual/R-devel/library/utils/html/globalVariables.html suppressForeignCheck()]


==== install.packages() ====
=== llply() ===
By default, install.packages() will check versions and install uninstalled packages shown in 'Depends', 'Imports', and 'LinkingTo' fields. See [http://cran.r-project.org/doc/manuals/r-release/R-exts.html R-exts] manual.
llply is equivalent to lapply except that it will preserve labels and can display a progress bar. This is handy if we want to do a crazy thing.
 
If we want to install packages listed in 'Suggests' field, we should specify it explicitly by using ''dependencies'' argument:
<pre>
<pre>
install.packages(XXXX, dependencies = c("Depends", "Imports", "Suggests", "LinkingTo"))
LLID2GOIDs <- lapply(rLLID, function(x) get("org.Hs.egGO")[[x]])
# OR
install.packages(XXXX, dependencies = TRUE)
</pre>
</pre>
For example, if I use a plain install.packages() command to install [http://cran.r-project.org/web/packages/downloader/index.html downloader] package
where rLLID is a list of entrez ID. For example,  
<pre>
<pre>
install.packages("downloader")
get("org.Hs.egGO")[["6772"]]
</pre>
</pre>  
it will only install 'digest' and 'downloader' packages. If I use
returns a list of 49 GOs.
<pre>
install.packages("downloader", dependencies=TRUE)
</pre>
it will also install 'testhat' package.


The '''install.packages''' function source code can be found in R -> src -> library -> utils -> R -> [https://github.com/wch/r-source/blob/trunk/src/library/utils/R/packages2.R packages2.R] file from [https://github.com/wch/r-source Github] repository (put 'install.packages' in the search box).
=== ddply() ===
http://lamages.blogspot.com/2012/06/transforming-subsets-of-data-in-r-with.html


==== install a tar.gz from a local directory ====
=== ldply() ===
<syntaxhighlight lang='bash'>
[http://rpsychologist.com/an-r-script-to-automatically-look-at-pubmed-citation-counts-by-year-of-publication/ An R Script to Automatically download PubMed Citation Counts By Year of Publication]
R CMD INSTALL <package-name>.tar.gz
</syntaxhighlight>
Or in R:
<syntaxhighlight lang='rsplus'>
install.packages(<pathtopackage>, repos = NULL, type="source")
</syntaxhighlight>


==== Query an R package installed locally ====
=== Performance/speed comparison ===
<pre>
[https://www.r-bloggers.com/2023/01/performance-comparison-of-converting-list-to-data-frame-with-r-language/ Performance comparison of converting list to data.frame with R language]
packageDescription("MASS")
packageVersion("MASS")
</pre>


==== Query an R package (from CRAN) basic information ====
== Using R's set.seed() to set seeds for use in C/C++ (including Rcpp) ==
<pre>
http://rorynolan.rbind.io/2018/09/30/rcsetseed/
packageStatus() # Summarize information about installed packages


available.packages() # List Available Packages at CRAN-like Repositories
=== get_seed() ===
See the same blog
{{Pre}}
get_seed <- function() {
  sample.int(.Machine$integer.max, 1)
}
</pre>
</pre>
The '''available.packages()''' command is useful for understanding package dependency. Use '''setRepositories()''' or 'RGUI -> Packages -> select repositories' to select repositories and '''options()$repos''' to check or change the repositories.
Note: .Machine$integer.max = 2147483647 = 2^31 - 1.


Also the '''packageStatus()''' is another useful function for query how many packages are in the repositories, how many have been installed, and individual package status (installed or not, needs to be upgraded or not).
=== Random seeds ===
By default, R uses the exact time in milliseconds of the computer's clock when R starts up to generate a seed. See [https://stat.ethz.ch/R-manual/R-patched/library/base/html/Random.html ?Random].  
<pre>
<pre>
> options()$repos
set.seed(as.numeric(Sys.time()))


> packageStatus()  
set.seed(as.numeric(Sys.Date()))  # same seed for each day
Number of installed packages:
</pre>
                                   
                                      ok upgrade unavailable
  C:/Program Files/R/R-3.0.1/library 110      0          1


Number of available packages (each package counted only once):
=== .Machine and the largest integer, double ===
                                                                                 
See [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/.Machine ?.Machine].  
                                                                                    installed not installed
{{Pre}}
  http://watson.nci.nih.gov/cran_mirror/bin/windows/contrib/3.0                            76          4563
                          Linux/Mac  32-bit Windows 64-bit Windows
  http://www.stats.ox.ac.uk/pub/RWin/bin/windows/contrib/3.0                                0            5
double.eps              2.220446e-16  2.220446e-16  2.220446e-16
  http://www.bioconductor.org/packages/2.12/bioc/bin/windows/contrib/3.0                  16           625
double.neg.eps          1.110223e-16   1.110223e-16  1.110223e-16
   http://www.bioconductor.org/packages/2.12/data/annotation/bin/windows/contrib/3.0        4          686
double.xmin            2.225074e-308  2.225074e-308  2.225074e-308
> tmp <- available.packages()
double.xmax            1.797693e+308 1.797693e+308  1.797693e+308
> str(tmp)
double.base            2.000000e+00  2.000000e+00  2.000000e+00
  chr [1:5975, 1:17] "A3" "ABCExtremes" "ABCp2" "ACCLMA" "ACD" "ACNE" "ADGofTest" "ADM3" "AER" ...
double.digits          5.300000e+01   5.300000e+01  5.300000e+01
- attr(*, "dimnames")=List of 2
double.rounding        5.000000e+00  5.000000e+00  5.000000e+00
   ..$ : chr [1:5975] "A3" "ABCExtremes" "ABCp2" "ACCLMA" ...
double.guard            0.000000e+00   0.000000e+00  0.000000e+00
   ..$ : chr [1:17] "Package" "Version" "Priority" "Depends" ...
double.ulp.digits      -5.200000e+01  -5.200000e+01  -5.200000e+01
> tmp[1:3,]
double.neg.ulp.digits  -5.300000e+01  -5.300000e+01  -5.300000e+01
            Package      Version Priority Depends                    Imports LinkingTo Suggests           
double.exponent        1.100000e+01  1.100000e+01  1.100000e+01
A3          "A3"          "0.9.2" NA      "xtable, pbapply"          NA      NA        "randomForest, e1071"
double.min.exp        -1.022000e+03  -1.022000e+03  -1.022000e+03
ABCExtremes "ABCExtremes" "1.0"   NA      "SpatialExtremes, combinat" NA      NA        NA                 
double.max.exp          1.024000e+03   1.024000e+03  1.024000e+03
ABCp2      "ABCp2"      "1.1"  NA      "MASS"                      NA      NA        NA                 
integer.max             2.147484e+09  2.147484e+09  2.147484e+09
             Enhances License      License_is_FOSS License_restricts_use OS_type Archs MD5sum NeedsCompilation File
sizeof.long             8.000000e+00  4.000000e+00  4.000000e+00
A3          NA      "GPL (>= 2)" NA              NA                    NA      NA    NA    NA              NA 
sizeof.longlong        8.000000e+00  8.000000e+00  8.000000e+00
ABCExtremes NA      "GPL-2"      NA              NA                    NA      NA    NA    NA              NA 
sizeof.longdouble      1.600000e+01  1.200000e+01  1.600000e+01
ABCp2      NA      "GPL-2"      NA              NA                    NA      NA    NA    NA              NA 
sizeof.pointer          8.000000e+00  4.000000e+00  8.000000e+00
             Repository                                                   
A3          "http://watson.nci.nih.gov/cran_mirror/bin/windows/contrib/3.0"
ABCExtremes "http://watson.nci.nih.gov/cran_mirror/bin/windows/contrib/3.0"
ABCp2      "http://watson.nci.nih.gov/cran_mirror/bin/windows/contrib/3.0"
</pre>
</pre>
And the following commands find which package depends on Rcpp and also which are from bioconductor repository.
 
=== NA when overflow ===
<pre>
<pre>
> pkgName <- "Rcpp"
tmp <- 156287L
> rownames(tmp)[grep(pkgName, tmp[,"Depends"])]
tmp*tmp
> tmp[grep("Rcpp", tmp[,"Depends"]), "Depends"]
# [1] NA
 
# Warning message:
> ind <- intersect(grep(pkgName, tmp[,"Depends"]), grep("bioconductor", tmp[, "Repository"]))
# In tmp * tmp : NAs produced by integer overflow
> rownames(grep)[ind]
.Machine$integer.max
NULL
# [1] 2147483647
> rownames(tmp)[ind]
[1] "ddgraph"            "DESeq2"            "GeneNetworkBuilder" "GOSemSim"          "GRENITS"         
[6] "mosaics"            "mzR"                "pcaMethods"        "Rdisop"            "Risa"             
[11] "rTANDEM"   
</pre>
</pre>


==== Install personal R packages after upgrade R, .libPaths() ====
== How to select a seed for simulation or randomization ==
Scenario: We already have installed many R packages under R 3.1.X in the user's directory. Now we upgrade R to a new version (3.2.X). We like to have these packages available in R 3.2.X.
* [https://sciprincess.wordpress.com/2019/03/14/how-to-select-a-seed-for-simulation-or-randomization/ How to select a seed for simulation or randomization]
* [https://www.makeuseof.com/tag/lesson-gamers-rng/ What Is RNG? A Lesson for Gamers ]


<span style="color:#0000FF">For Windows OS, refer to [http://cran.r-project.org/bin/windows/base/rw-FAQ.html#What_0027s-the-best-way-to-upgrade_003f R for Windows FAQ]</span>
== set.seed() allow alphanumeric seeds ==
https://stackoverflow.com/a/10913336


The follow method works on Linux and Windows.
== set.seed(), for loop and saving random seeds ==
 
<ul>
<span style="color:#FF0000">Make sure only one instance of R is running</span>
<li>[https://www.jottr.org/2020/09/21/detect-when-the-random-number-generator-was-used/ Detect When the Random Number Generator Was Used]
<pre>
<pre>
# Step 1. update R's built-in packages and install them on my personal directory
if (interactive()) {
update.packages(ask=FALSE, checkBuilt = TRUE, repos="http://cran.rstudio.com")
  invisible(addTaskCallback(local({
    last <- .GlobalEnv$.Random.seed
   
    function(...) {
      curr <- .GlobalEnv$.Random.seed
      if (!identical(curr, last)) {
        msg <- "NOTE: .Random.seed changed"
        if (requireNamespace("crayon", quietly=TRUE)) msg <- crayon::blurred(msg)
        message(msg)
        last <<- curr
      }
      TRUE
    }
  }), name = "RNG tracker"))
}
</pre>
</li>
<li>http://r.789695.n4.nabble.com/set-seed-and-for-loop-td3585857.html. This question is legitimate when we want to debug on a certain iteration.
<pre>
set.seed(1001)
data <- vector("list", 30)
seeds <- vector("list", 30)  
for(i in 1:30) {
  seeds[[i]] <- .Random.seed
  data[[i]] <- runif(5)
}
# If we save and load .Random.seed from a file using scan(), make
# sure to convert its type from doubles to integers.
# Otherwise, .Random.seed will complain!


# Step 2. update Bioconductor packages
.Random.seed <- seeds[[23]] # restore
.libPaths() # The first one is my personal directory
data.23 <- runif(5)  
# [1] "/home/brb/R/x86_64-pc-linux-gnu-library/3.2"
data.23
# [2] "/usr/local/lib/R/site-library"
data[[23]]  
# [3] "/usr/lib/R/site-library"
# [4] "/usr/lib/R/library"
 
Sys.getenv("R_LIBS_USER") # equivalent to .libPaths()[1]
ul <- unlist(strsplit(Sys.getenv("R_LIBS_USER"), "/"))
src <- file.path(paste(ul[1:(length(ul)-1)], collapse="/"), "3.1")
des <- file.path(paste(ul[1:(length(ul)-1)], collapse="/"), "3.2")
pkg <- dir(src, full.names = TRUE)
if (!file.exists(des)) dir.create(des)  # If 3.2 subdirectory does not exist yet!
file.copy(pkg, des, overwrite=FALSE, recursive = TRUE)
source("http://www.bioconductor.org/biocLite.R")
biocLite(ask = FALSE)
</pre>
</pre>
</li>
</ul>
* [https://www.rdocumentation.org/packages/impute/versions/1.46.0/topics/impute.knn impute.knn]
* Duncan Murdoch: ''This works in this example, but wouldn't work with all RNGs, because some of them save state outside of .Random.seed.  See ?.Random.seed for details.''
* Uwe Ligges's comment: ''set.seed() actually generates a seed. See ?set.seed that points us to .Random.seed (and relevant references!) which contains the actual current seed.''
* Petr Savicky's comment is also useful in the situation when it is not difficult to re-generate the data.
* [http://www.questionflow.org/2019/08/13/local-randomness-in-r/ Local randomness in R].


<span style="color:#0000FF">From Robert Kabacoff (R in Action)</span>
== sample() ==
* If you have a customized '''Rprofile.site file''' (see appendix B), save a copy outside of R.
=== sample() inaccurate on very large populations, fixed in R 3.6.0 ===
* Launch your current version of R and issue the following statements
* [https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17494 The default method for generating from a discrete uniform distribution (used in ‘sample(), for instance) has been changed]. In prior versions, the probability of generating each integer could vary from equal by up to 0.04% (or possibly more if generating more than a million different integers). See also [https://www.r-bloggers.com/whats-new-in-r-3-6-0/amp/ What's new in R 3.6.0] by David Smith.  
<pre>
{{Pre}}
oldip <- installed.packages()[,1]
# R 3.5.3
save(oldip, file="path/installedPackages.Rdata")
set.seed(123)
</pre>
m <- (2/5)*2^32
where ''path'' is a directory outside of R.
m > 2^31
* Download and install the newer version of R.
# [1] FALSE
* If you saved a customized version of the Rprofile.site file in step 1, copy it into the new installation.
log10(m)
* Launch the new version of R, and issue the following statements
# [1] 9.23502
<pre>
x <- sample(m, 1000000, replace = TRUE)
load("path/installedPackages.Rdata")
table(x %% 2)
newip <- installed.packages()[,1]
#      0      1
for(i in setdiff(oldip, newip))
# 400070 599930
  install.packages(i)
</pre>
</pre>
where path is the location specified in step 2.
* [https://blog.daqana.com/en/fast-sampling-support-in-dqrng/ Fast sampling support in dqrng]
* Delete the old installation (optional).
* Differences of the output of sample()  
{{Pre}}
# R 3.5.3
# docker run --net=host -it --rm r-base:3.5.3
> set.seed(1234)
> sample(5)
[1] 1 3 2 4 5


This approach will install only packages that are available from the CRAN. It won’t find packages obtained from other locations. In fact, the process will display a list of packages that can’t be installed For example for packages obtained from Bioconductor, use the following method to update packages
# R 3.6.0
<pre>
# docker run --net=host -it --rm r-base:3.6.0
source(http://bioconductor.org/biocLite.R)
> set.seed(1234)
biocLite(PKGNAME)
> sample(5)
[1] 4 5 2 3 1
> RNGkind(sample.kind = "Rounding")
Warning message:
In RNGkind(sample.kind = "Rounding") : non-uniform 'Rounding' sampler used
> set.seed(1234)
> sample(5)
[1] 1 3 2 4 5
</pre>
</pre>


==== List vignettes from a package ====
=== Getting different results with set.seed() in RStudio ===
<syntaxhighlight lang='rsplus'>
[https://community.rstudio.com/t/getting-different-results-with-set-seed/31624/2 Getting different results with set.seed()].  ''It's possible that you're loading an R package that is changing the requested random number generator; RNGkind().''
vignette(package=PACKAGENAME)
</syntaxhighlight>


==== List data from a package ====
=== dplyr::sample_n() ===
<syntaxhighlight lang='rsplus'>
The function has a parameter [https://dplyr.tidyverse.org/reference/sample.html weight]. For example if we have some download statistics for each day and we want to do sampling based on their download numbers, we can use this function.
data(package=PACKAGENAME)
</syntaxhighlight>


==== List installed packages and versions ====
== Regular Expression ==
* http://heuristicandrew.blogspot.com/2015/06/list-of-user-installed-r-packages-and.html
See [[Regular_expression|here]].
* [http://cran.r-project.org/web/packages/checkpoint/index.html checkpoint] package


<syntaxhighlight lang='rsplus'>
== Read rrd file ==
ip <- as.data.frame(installed.packages()[,c(1,3:4)])
* https://en.wikipedia.org/wiki/RRDtool
rownames(ip) <- NULL
* http://oss.oetiker.ch/rrdtool/
unique(ip$Priority)
* https://github.com/pldimitrov/Rrd
# [1] <NA>        base        recommended
* http://plamendimitrov.net/blog/2014/08/09/r-package-for-working-with-rrd-files/
# Levels: base recommended
ip <- ip[is.na(ip$Priority),1:2,drop=FALSE]
print(ip, row.names=FALSE)
</syntaxhighlight>


==== Query the names of outdated packages ====
== on.exit() ==
Examples of using on.exit(). In all these examples, '''add = TRUE''' is used in the on.exit() call to ensure that each exit action is added to the list of actions to be performed when the function exits, rather than replacing the previous actions.
<ul>
<li>Database connections
<pre>
<pre>
psi <- packageStatus()$inst
library(RSQLite)
subset(psi, Status == "upgrade", drop = FALSE)
sqlite_get_query <- function(db, sql) {
#                    Package                                  LibPath    Version    Priority                Depends
  conn <- dbConnect(RSQLite::SQLite(), db)
# RcppArmadillo RcppArmadillo C:/Users/brb/Documents/R/win-library/3.2 0.5.100.1.0        <NA>                  <NA>
  on.exit(dbDisconnect(conn), add = TRUE)
# Matrix              Matrix      C:/Program Files/R/R-3.2.0/library      1.2-0 recommended R (>= 2.15.2), methods
   dbGetQuery(conn, sql)
#                                            Imports LinkingTo                Suggests
}
# RcppArmadillo                      Rcpp (>= 0.11.0)     Rcpp RUnit, Matrix, pkgKitten
# Matrix        graphics, grid, stats, utils, lattice      <NA>              expm, MASS
#                                            Enhances    License License_is_FOSS License_restricts_use OS_type MD5sum
# RcppArmadillo                                  <NA> GPL (>= 2)           <NA>                  <NA>    <NA>   <NA>
# Matrix        MatrixModels, graph, SparseM, sfsmisc GPL (>= 2)           <NA>                  <NA>    <NA>  <NA>
#              NeedsCompilation Built  Status
# RcppArmadillo              yes 3.2.0 upgrade
# Matrix                    yes 3.2.0 upgrade
</pre>
</pre>
 
<li>File connections
The above output does not show the package version from the latest packages on CRAN. So the following snippet does that.
<pre>
read_chars <- function(file_name) {
  conn <- file(file_name, "r")
  on.exit(close(conn), add = TRUE)
  readChar(conn, file.info(file_name)$size)
}
</pre>
<li>Temporary files
<pre>
<pre>
psi <- packageStatus()$inst
history_lines <- function() {
pl <- unname(psi$Package[psi$Status == "upgrade"]) # List package names
  f <- tempfile()
 
  on.exit(unlink(f), add = TRUE)
out <- cbind(subset(psi, Status == "upgrade")[, c("Package", "Version")], ap[match(pl, ap$Package), "Version"])
  savehistory(f)
colnames(out)[2:3] <- c("OldVersion", "NewVersion")
  readLines(f, encoding = "UTF-8")
rownames(out) <- NULL
}
out
#        Package  OldVersion  NewVersion
# 1 RcppArmadillo 0.5.100.1.0 0.5.200.1.0
# 2        Matrix      1.2-0      1.2-1
</pre>
</pre>
 
<li>Printing messages
To consider also the packages from Bioconductor, we have the following code. Note that "3.1" means the Bioconductor version and "3.2" is the R version. See [http://bioconductor.org/about/release-announcements/#release-versions Bioconductor release versions] page.
<pre>
<pre>
psic <- packageStatus(repos = c(contrib.url(getOption("repos")),
myfun = function(x) {
                                "http://bioconductor.org/packages/3.1/bioc/bin/windows/contrib/3.2",
  on.exit(print("first"))
                                "http://www.bioconductor.org/packages/3.1/data/annotation/bin/windows/contrib/3.2"))$inst
  on.exit(print("second"), add = TRUE)
subset(psic, Status == "upgrade", drop = FALSE)
  return(x)
pl <- unname(psic$Package[psic$Status == "upgrade"])
}
</pre>
</ul>


# ap <- as.data.frame(available.packages()[, c(1,2,3)], stringsAsFactors = FALSE)
== file, connection ==
ap  <- as.data.frame(available.packages(c(contrib.url(getOption("repos")),
* [https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/cat cat()] and [https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/scan scan()] (read data into a vector or list from the console or file)
                                "http://bioconductor.org/packages/3.1/bioc/bin/windows/contrib/3.2",
* read() and write()
                                "http://www.bioconductor.org/packages/3.1/data/annotation/bin/windows/contrib/3.2"))[, c(1:3)],  
* read.table() and write.table()
                      stringAsFactors = FALSE)
{{Pre}}
out = file('tmp.txt', 'w')
writeLines("abcd", out)
writeLines("eeeeee", out)
close(out)
readLines('tmp.txt')
unlink('tmp.txt')
args(writeLines)
# function (text, con = stdout(), sep = "\n", useBytes = FALSE)


out <- cbind(subset(psic, Status == "upgrade")[, c("Package", "Version")], ap[match(pl, ap$Package), "Version"])
foo <- function() {
colnames(out)[2:3] <- c("OldVersion", "NewVersion")
  con <- file()
rownames(out) <- NULL
  ...
out
  on.exit(close(con))
#        Package  OldVersion  NewVersion
  ...
# 1        limma      3.24.5      3.24.9
}
# 2 RcppArmadillo 0.5.100.1.0 0.5.200.1.0
</pre>
# 3        Matrix      1.2-0      1.2-1
[https://r.789695.n4.nabble.com/Why-I-get-this-error-Error-in-close-connection-f-invalid-connection-td904413.html Error in close.connection(f) : invalid connection]. If we want to use '''close(con)''', we have to specify how to '''open''' the connection; such as
<pre>
con <- gzfile(FileName, "r") # Or gzfile(FileName, open = 'r')
x <- read.delim(con)
close(x)
</pre>
</pre>


==== Fishing for packages in CRAN ====
=== withr package ===
* http://blog.revolutionanalytics.com/2015/06/fishing-for-packages-in-cran.html
https://cran.r-project.org/web/packages/withr/index.html . Reverse suggested by [https://cran.r-project.org/web/packages/languageserver/index.html languageserver].


==== Query top downloaded packages ====
== Clipboard (?connections), textConnection(), pipe() ==
* [https://github.com/metacran/cranlogs cranlogs] package - Download Logs from the RStudio CRAN Mirror
<ul>
* http://blog.revolutionanalytics.com/2015/06/working-with-the-rstudio-cran-logs.html
<li>On Windows, we can use readClipboard() and writeClipboard().
 
{{Pre}}
==== Top new packages in 2015 ====
source("clipboard")
* [http://opiateforthemass.es/articles/R-packages-in-2015/ 2015 R packages roundup] by CHRISTOPH SAFFERLING
read.table("clipboard")
* [http://gforge.se/2016/01/r-trends-in-2015/ R trends in 2015] by MAX GORDON
</pre></li>
<li>Clipboard -> R. Reading/writing clipboard on macOS. Use [https://www.rdocumentation.org/packages/base/versions/3.5.0/topics/textConnection textConnection()] function:
{{Pre}}
x <- read.delim(textConnection("<USE_KEYBOARD_TO_PASTE_FROM_CLIPBOARD>"))
# Or on Mac
x <- read.delim(pipe("pbpaste"))
# safely ignore the warning: incomplete final line found by readTableHeader on 'pbpaste'
</pre>
An example is to copy data from [https://stackoverflow.com/questions/28426026/plotting-boxplots-of-multiple-y-variables-using-ggplot2-qplot-or-others?answertab=active#tab-top this post]. In this case we need to use read.table() instead of read.delim().
</li>
<li>R -> clipboard on Mac. Note: '''pbcopy''' and '''pbpaste''' are macOS terminal commands. See [http://osxdaily.com/2007/03/05/manipulating-the-clipboard-from-the-command-line/ pbcopy & pbpaste: Manipulating the Clipboard from the Command Line].  
* pbcopy: takes standard input and places it in the clipboard buffer
* pbpaste: takes data from the clipboard buffer and writes it to the standard output
{{Pre}}
clip <- pipe("pbcopy", "w")
write.table(apply(x, 1, mean), file = clip, row.names=F, col.names=F)
# write.table(data.frame(Var1, Var2), file = clip, row.names=F, quote=F, sep="\t")
close(clip)
</pre>
<li>
<li>Clipboard -> Excel.
* Method 1: Paste icon -> Text import wizard -> Delimit (Tab, uncheck Space) or Fixed width depending on the situation -> Finish.
* Method 2: Ctrl+v first. Then choose Data -> Text to Columns. Fixed width -> Next -> Next -> Finish.
</li>
<li>On Linux, we need to install "xclip". See [https://stackoverflow.com/questions/45799496/r-copy-from-clipboard-in-ubuntu-linux R Copy from Clipboard in Ubuntu Linux]. It seems to work.
{{Pre}}
# sudo apt-get install xclip
read.table(pipe("xclip -selection clipboard -o",open="r"))
</pre>
</li>
</ul>


==== Warning: cannot remove prior installation of package ====
=== clipr ===
http://stackoverflow.com/questions/15932152/unloading-and-removing-a-loaded-package-withouth-restarting-r
[https://cran.rstudio.com/web/packages/clipr/ clipr]: Read and Write from the System Clipboard


Instance 1.
== read/manipulate binary data ==
<pre>
* x <- readBin(fn, raw(), file.info(fn)$size)
# Install the latest hgu133plus2cdf package
* rawToChar(x[1:16])
# Remove/Uninstall hgu133plus2.db package
* See Biostrings C API
# Put/Install an old version of IRanges (eg version 1.18.2 while currently it is version 1.18.3)
# Test on R 3.0.1
library(hgu133plus2cdf) # hgu133pluscdf does not depend or import IRanges
source("http://bioconductor.org/biocLite.R")
biocLite("hgu133plus2.db", ask=FALSE) # hgu133plus2.db imports IRanges
# Warning:cannot remove prior installation of package 'IRanges'
# Open Windows Explorer and check IRanges folder. Only see libs subfolder.
</pre>


Note:
== String Manipulation ==
* In the above example, all packages were installed under C:\Program Files\R\R-3.0.1\library\.
* [https://www.gastonsanchez.com/r4strings/ Handling Strings with R](ebook) by Gaston Sanchez.
* In another instance where I cannot reproduce the problem, new R packages were installed under C:\Users\xxx\Documents\R\win-library\3.0\. The different thing is IRanges package CAN be updated but if I use packageVersion("IRanges") command in R, it still shows the old version.
* [http://blog.revolutionanalytics.com/2018/06/handling-strings-with-r.html A guide to working with character data in R] (6/22/2018)
* The above were tested on a desktop.
* Chapter 7 of the book 'Data Manipulation with R' by Phil Spector.
* Chapter 7 of the book 'R Cookbook' by Paul Teetor.
* Chapter 2 of the book 'Using R for Data Management, Statistical Analysis and Graphics' by Horton and Kleinman.
* http://www.endmemo.com/program/R/deparse.php. '''It includes lots of examples for each R function it lists.'''
* [http://theautomatic.net/2019/05/17/four-ways-to-reverse-a-string-in-r/ Four ways to reverse a string in R]
* [https://statisticaloddsandends.wordpress.com/2022/05/05/a-short-note-on-the-startswith-function/ A short note on the startsWith function]


Instance 2.
=== format(): padding with zero ===
<pre>
<pre>
# On a fresh R 3.2.0, I install Bioconductor's depPkgTools & lumi packages. Then I close R, re-open it,
ngenes <- 10
# and install depPkgTools package again.
genenames <- paste0("bm", gsub(" ", "0", format(1:ngenes))); genenames
> source("http://bioconductor.org/biocLite.R")
#  [1] "bm01" "bm02" "bm03" "bm04" "bm05" "bm06" "bm07" "bm08" "bm09" "bm10"
Bioconductor version 3.1 (BiocInstaller 1.18.2), ?biocLite for help
> biocLite("pkgDepTools")
BioC_mirror: http://bioconductor.org
Using Bioconductor version 3.1 (BiocInstaller 1.18.2), R version 3.2.0.
Installing package(s) ‘pkgDepTools’
trying URL 'http://bioconductor.org/packages/3.1/bioc/bin/windows/contrib/3.2/pkgDepTools_1.34.0.zip'
Content type 'application/zip' length 390579 bytes (381 KB)
downloaded 381 KB
 
package ‘pkgDepTools’ successfully unpacked and MD5 sums checked
Warning: cannot remove prior installation of package ‘pkgDepTools’
 
The downloaded binary packages are in
        C:\Users\brb\AppData\Local\Temp\RtmpYd2l7i\downloaded_packages
> library(pkgDepTools)
Error in library(pkgDepTools) : there is no package called ‘pkgDepTools’
</pre>
</pre>
The pkgDepTools library folder appears in C:\Users\brb\Documents\R\win-library\3.2, but it is empty. The weird thing is if I try the above steps again, I cannot reproduce the problem.
==== Warning: Unable to move temporary installation ====
The problem seems to happen only on virtual machines (Virtualbox).
* '''Warning: unable to move temporary installation `C:\Users\brb\Documents\R\win-library\3.0\fileed8270978f5\quadprog`  to `C:\Users\brb\Documents\R\win-library\3.0\quadprog`''' when I try to run 'install.packages("forecast").
* '''Warning: unable to move temporary installation ‘C:\Users\brb\Documents\R\win-library\3.2\file5e0104b5b49\plyr’ to ‘C:\Users\brb\Documents\R\win-library\3.2\plyr’ ''' when I try to run 'biocLite("lumi")'. The other dependency packages look fine although I am not sure if any unknown problem can happen (it does, see below).
Here is a note of my trouble shooting.
# If I try to ignore the warning and load the lumi package. I will get an error.
# If I try to run biocLite("lumi") again, it will only download & install lumi without checking missing 'plyr' package. Therefore, when I try to load the lumi package, it will give me an error again.
# Even I install the plyr package manually, library(lumi) gives another error - missing mclust package.
<pre>
> biocLite("lumi")
trying URL 'http://bioconductor.org/packages/3.1/bioc/bin/windows/contrib/3.2/BiocInstaller_1.18.2.zip'
Content type 'application/zip' length 114097 bytes (111 KB)
downloaded 111 KB
...
package ‘lumi’ successfully unpacked and MD5 sums checked


The downloaded binary packages are in
=== noquote() ===
        C:\Users\brb\AppData\Local\Temp\RtmpyUjsJD\downloaded_packages
[https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/noquote noqute] Print character strings without quotes.
Old packages: 'BiocParallel', 'Biostrings', 'caret', 'DESeq2', 'gdata', 'GenomicFeatures', 'gplots', 'Hmisc', 'Rcpp', 'RcppArmadillo', 'rgl',
  'stringr'
Update all/some/none? [a/s/n]: a
also installing the dependencies ‘Rsamtools’, ‘GenomicAlignments’, ‘plyr’, ‘rtracklayer’, ‘gridExtra’, ‘stringi’, ‘magrittr’


trying URL 'http://bioconductor.org/packages/3.1/bioc/bin/windows/contrib/3.2/Rsamtools_1.20.1.zip'
=== stringr package ===
Content type 'application/zip' length 8138197 bytes (7.8 MB)
* https://stringr.tidyverse.org/index.html
downloaded 7.8 MB
* [https://stringr.tidyverse.org/articles/from-base.html Vignette compares stringr functions to their base R equivalents]
...
* When I try to use trimws() on data obtained from readxl::read_excell(), I find trimws() does not work but [https://stringr.tidyverse.org/reference/str_trim.html stringr::str_trim()] works. [https://stackoverflow.com/questions/45050617/trimws-bug-leading-whitespace-not-removed trimws bug? leading whitespace not removed].
package ‘Rsamtools’ successfully unpacked and MD5 sums checked
package ‘GenomicAlignments’ successfully unpacked and MD5 sums checked
package ‘plyr’ successfully unpacked and MD5 sums checked
Warning: unable to move temporary installation ‘C:\Users\brb\Documents\R\win-library\3.2\file5e0104b5b49\plyr’
        to ‘C:\Users\brb\Documents\R\win-library\3.2\plyr’
package ‘rtracklayer’ successfully unpacked and MD5 sums checked
package ‘gridExtra’ successfully unpacked and MD5 sums checked
package ‘stringi’ successfully unpacked and MD5 sums checked
package ‘magrittr’ successfully unpacked and MD5 sums checked
package ‘BiocParallel’ successfully unpacked and MD5 sums checked
package ‘Biostrings’ successfully unpacked and MD5 sums checked
Warning: cannot remove prior installation of package ‘Biostrings’
package ‘caret’ successfully unpacked and MD5 sums checked
package ‘DESeq2’ successfully unpacked and MD5 sums checked
package ‘gdata’ successfully unpacked and MD5 sums checked
package ‘GenomicFeatures’ successfully unpacked and MD5 sums checked
package ‘gplots’ successfully unpacked and MD5 sums checked
package ‘Hmisc’ successfully unpacked and MD5 sums checked
package ‘Rcpp’ successfully unpacked and MD5 sums checked
package ‘RcppArmadillo’ successfully unpacked and MD5 sums checked
package ‘rgl’ successfully unpacked and MD5 sums checked
package ‘stringr’ successfully unpacked and MD5 sums checked


The downloaded binary packages are in
=== glue package ===
        C:\Users\brb\AppData\Local\Temp\RtmpyUjsJD\downloaded_packages
<ul>
> library(lumi)
<li>[https://cran.r-project.org/web/packages/glue/index.html glue]. Useful in a loop and some function like ggtitle() or ggsave(). Inside the curly braces {R-Expression}, the expression is evaluated.
Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]) :
<syntaxhighlight lang='r'>
  there is no package called ‘plyr’
library(glue)
Error: package or namespace load failed for ‘lumi’
name <- "John"
> search()
age <- 30
[1] ".GlobalEnv"            "package:BiocInstaller" "package:Biobase"      "package:BiocGenerics"  "package:parallel"      "package:stats"       
glue("My name is {name} and I am {age} years old.")
[7] "package:graphics"      "package:grDevices"    "package:utils"        "package:datasets"      "package:methods"      "Autoloads"           
# My name is John and I am 30 years old.
[13] "package:base"       
> biocLite("lumi")
BioC_mirror: http://bioconductor.org
Using Bioconductor version 3.1 (BiocInstaller 1.18.2), R version 3.2.0.
Installing package(s) ‘lumi’
trying URL 'http://bioconductor.org/packages/3.1/bioc/bin/windows/contrib/3.2/lumi_2.20.1.zip'
Content type 'application/zip' length 18185326 bytes (17.3 MB)
downloaded 17.3 MB


package ‘lumi’ successfully unpacked and MD5 sums checked
price <- 9.99
quantity <- 3
total <- glue("The total cost is {round(price * quantity, 2)}.")
# Inside the curly braces {}, the expression round(price * quantity, 2) is evaluated.
print(total)
# The total cost is 29.97.
</syntaxhighlight>
The syntax of glue() in R is quite similar to Python's print() function when using formatted strings. In Python, you typically use [https://www.pythontutorial.net/python-basics/python-f-strings/ f-strings] to embed variables inside strings.
<syntaxhighlight lang='python'>
name = "John"
age = 30
print(f"My name is {name} and I am {age} years old.")
# My name is John and I am 30 years old.


The downloaded binary packages are in
price = 9.99
        C:\Users\brb\AppData\Local\Temp\RtmpyUjsJD\downloaded_packages
quantity = 3
> search()
total = f"The total cost is {price * quantity:.2f}."
[1] ".GlobalEnv"            "package:BiocInstaller" "package:Biobase"      "package:BiocGenerics"  "package:parallel"      "package:stats"       
print(total)
[7] "package:graphics"      "package:grDevices"    "package:utils"        "package:datasets"      "package:methods"      "Autoloads"           
# The total cost is 29.97.
[13] "package:base"       
</syntaxhighlight>
> library(lumi)
Error in loadNamespace(i, c(lib.loc, .libPaths()), versionCheck = vI[[i]]) :
  there is no package called ‘plyr’
Error: package or namespace load failed for ‘lumi’
> biocLite("plyr")
BioC_mirror: http://bioconductor.org
Using Bioconductor version 3.1 (BiocInstaller 1.18.2), R version 3.2.0.
Installing package(s) ‘plyr’
trying URL 'http://cran.rstudio.com/bin/windows/contrib/3.2/plyr_1.8.2.zip'
Content type 'application/zip' length 1128621 bytes (1.1 MB)
downloaded 1.1 MB


package ‘plyr’ successfully unpacked and MD5 sums checked
</li>
<li>[https://en.wikipedia.org/wiki/String_interpolation String interpolation] </li>
</ul>


The downloaded binary packages are in
=== Raw data type ===
        C:\Users\brb\AppData\Local\Temp\RtmpyUjsJD\downloaded_packages
[https://twitter.com/hadleywickham/status/1387747735441395712 Fun with strings], [https://en.wikipedia.org/wiki/Cyrillic_alphabets Cyrillic alphabets]
<pre>
a1 <- "А"
a2 <- "A"
a1 == a2
# [1] FALSE
charToRaw("А")
# [1] d0 90
charToRaw("A")
# [1] 41
</pre>


> library(lumi)
=== number of characters limit ===
Error in loadNamespace(j <- i[[1L]], c(lib.loc, .libPaths()), versionCheck = vI[[j]]) :
[https://twitter.com/eddelbuettel/status/1438326822635180036 It's a limit on a (single) input line in the REPL]
  there is no package called ‘mclust’
Error: package or namespace load failed for ‘lumi’


> ?biocLite
=== Comparing strings to numeric ===
Warning messages:
[https://stackoverflow.com/a/57348393 ">" coerces the number to a string before comparing].
1: In read.dcf(file.path(p, "DESCRIPTION"), c("Package", "Version")) :
<syntaxhighlight lang='r' inline>"10" < 2 # TRUE</syntaxhighlight>
  cannot open compressed file 'C:/Users/brb/Documents/R/win-library/3.2/Biostrings/DESCRIPTION', probable reason 'No such file or directory'
2: In find.package(if (is.null(package)) loadedNamespaces() else package,  :
  there is no package called ‘Biostrings’
> library(lumi)
Error in loadNamespace(j <- i[[1L]], c(lib.loc, .libPaths()), versionCheck = vI[[j]]) :
  there is no package called ‘mclust’
In addition: Warning messages:
1: In read.dcf(file.path(p, "DESCRIPTION"), c("Package", "Version")) :
  cannot open compressed file 'C:/Users/brb/Documents/R/win-library/3.2/Biostrings/DESCRIPTION', probable reason 'No such file or directory'
2: In find.package(if (is.null(package)) loadedNamespaces() else package,  :
  there is no package called ‘Biostrings’
Error: package or namespace load failed for ‘lumi’
</pre>


[http://r.789695.n4.nabble.com/unable-to-move-temporary-installation-td4521714.html Other people also have the similar problem]. The possible cause is the virus scanner locks the file and R cannot move them.
== HTTPs connection ==
HTTPS connection becomes default in R 3.2.2. See
* http://blog.rstudio.org/2015/08/17/secure-https-connections-for-r/
* http://blog.revolutionanalytics.com/2015/08/good-advice-for-security-with-r.html


Some possible solutions:
[http://developer.r-project.org/blosxom.cgi/R-devel/2016/12/15#n2016-12-15 R 3.3.2 patched] The internal methods of ‘download.file()and ‘url()’ now report if they are unable to follow the redirection of a ‘http://’ URL to a ‘https://’ URL (rather than failing silently)
# Delete ALL folders under R/library (e.g. C:/Progra~1/R/R-3.2.0/library) folder and install the main package again using install.packages() or biocLite().
# For specific package like 'lumi' from Bioconductor, we can [[R#Bioconductor.27s_pkgDepTools_package|find out all dependency packages]] and then install them one by one.
# Find out and install the top level package which misses dependency packages.
## This is based on the fact that install.packages() or biocLite() '''sometimes''' just checks & installs the 'Depends' and 'Imports' packages and '''won't install all packages recursively'''
## we can do a small experiment by removing a package which is not directly dependent/imported by another package; e.g. 'iterators' is not dependent/imported by 'glment' directly but indirectly. So if we run '''remove.packages("iterators"); install.packages("glmnet")''', then the 'iterator' package is still missing.
## A real example is if the missing packages are 'Biostrings', 'limma', 'mclust' (these are packages that 'minfi' directly depends/imports although they should be installed when I run biocLite("lumi") command), then I should just run the command '''remove.packages("minfi"); biocLite("minfi")'''. If we just run biocLite("lumi") or biocLite("methylumi"), the missing packages won't be installed.


==== Error in download.file(url, destfile, method, mode = "wb", ...) and cache ====
== setInternet2 ==
HTTP status was '404 Not Found'
There was a bug in ftp downloading in R 3.2.2 (r69053) Windows though it is fixed now in R 3.2 patch.


Tested on an existing R-3.2.0 session. Note that VariantAnnotation 1.14.4 was just uploaded to Bioc.
Read the [https://stat.ethz.ch/pipermail/r-devel/2015-August/071595.html discussion] reported on 8/8/2015. The error only happened on ftp not http connection. The final solution is explained in [https://stat.ethz.ch/pipermail/r-devel/2015-August/071623.html this post]. The following demonstrated the original problem.
<pre>
<pre>
> biocLite("COSMIC.67")
url <- paste0("ftp://ftp.ncbi.nlm.nih.gov/genomes/ASSEMBLY_REPORTS/All/",
BioC_mirror: http://bioconductor.org
              "GCF_000001405.13.assembly.txt")
Using Bioconductor version 3.1 (BiocInstaller 1.18.3), R version 3.2.0.
f1 <- tempfile()
Installing package(s) ‘COSMIC.67’
download.file(url, f1)
also installing the dependency ‘VariantAnnotation’
</pre>
 
It seems the bug was fixed in R 3.2-branch. See [https://github.com/wch/r-source/commit/3a02ed3a50ba17d9a093b315bf5f31ffc0e21b89 8/16/2015] patch r69089 where a new argument INTERNET_FLAG_PASSIVE was added to [https://msdn.microsoft.com/en-us/library/windows/desktop/aa385098%28v=vs.85%29.aspx InternetOpenUrl()] function of [https://msdn.microsoft.com/en-us/library/windows/desktop/aa385473%28v=vs.85%29.aspx wininet] library. [http://slacksite.com/other/ftp.html This article] and [http://stackoverflow.com/questions/1699145/what-is-the-difference-between-active-and-passive-ftp this post] explain differences of active and passive FTP.  
trying URL 'http://bioconductor.org/packages/3.1/bioc/bin/windows/contrib/3.2/VariantAnnotation_1.14.3.zip'
Error in download.file(url, destfile, method, mode = "wb", ...) :
  cannot open URL 'http://bioconductor.org/packages/3.1/bioc/bin/windows/contrib/3.2/VariantAnnotation_1.14.3.zip'
In addition: Warning message:
In download.file(url, destfile, method, mode = "wb", ...) :
  cannot open: HTTP status was '404 Not Found'
Warning in download.packages(pkgs, destdir = tmpd, available = available,  :
  download of package ‘VariantAnnotation’ failed
installing the source package ‘COSMIC.67’


trying URL 'http://bioconductor.org/packages/3.1/data/experiment/src/contrib/COSMIC.67_1.4.0.tar.gz'
The following R command will show the exact svn revision for the R you are currently using.
Content type 'application/x-gzip' length 40999037 bytes (39.1 MB)
<pre>
R.Version()$"svn rev"
</pre>
</pre>


However, when I tested on a new R-3.2.0 (just installed in VM), the COSMIC package installation is successful. That VariantAnnotation version 1.14.4 was installed (this version was just updated today from Bioconductor).
If setInternet2(T), then https protocol is supported in download.file().  


The cause of the error is the '''[https://github.com/wch/r-source/blob/trunk/src/library/utils/R/packages.R available.package()]''' function will read the rds file first from cache in a tempdir (C:\Users\XXXX\AppData\Local\Temp\RtmpYYYYYY). See lines 51-55 of <packages.R>.
When setInternet(T) is enabled by default, download.file() does not work for ftp protocol (this is used in getGEO() function of the GEOquery package). If I use setInternet(F), download.file() works again for ftp protocol.  
<pre>
dest <- file.path(tempdir(),
                  paste0("repos_", URLencode(repos, TRUE), ".rds"))
if(file.exists(dest)) {
    res0 <- readRDS(dest)
} else {
    ...
</pre>
Since my R was opened 1 week ago, the rds file it reads today contains old information. Note that Bioconductor does not hold the source code or binary code for the old version of packages. This explains why biocLite() function broke. When I restart R, the original problem is gone.


If we look at the source code of available.packages(), we will see we could use '''cacheOK''' option in download.file() function.
The setInternet2() function is defined in [https://github.com/wch/r-source/commits/trunk/src/library/utils/R/windows/sysutils.R R> src> library> utils > R > windows > sysutils.R].
<pre>
download.file(url, destfile, method, cacheOK = FALSE, quiet = TRUE, mode ="wb")
</pre>


==== Error in unloadNamespace(package) ====
'''R up to 3.2.2'''
<pre>
<pre>
> d3heatmap(mtcars, scale = "column", colors = "Blues")
setInternet2 <- function(use = TRUE) .Internal(useInternet2(use))
Error: 'col_numeric' is not an exported object from 'namespace:scales'
> packageVersion("scales")
[1] ‘0.2.5’
> library(scales)
Error in unloadNamespace(package) :
  namespace ‘scales’ is imported by ‘ggplot2’ so cannot be unloaded
In addition: Warning message:
package ‘scales’ was built under R version 3.2.1
Error in library(scales) :
  Package ‘scales’ version 0.2.4 cannot be unloaded
> search()
[1] ".GlobalEnv"            "package:d3heatmap"      "package:ggplot2"     
[4] "package:microbenchmark" "package:COSMIC.67"      "package:BiocInstaller"
[7] "package:stats"          "package:graphics"      "package:grDevices"   
[10] "package:utils"          "package:datasets"      "package:methods"     
[13] "Autoloads"              "package:base"
</pre>
</pre>
If I open a new R session, the above error will not happen!
See also
* <src/include/Internal.h> (declare do_setInternet2()),  
* <src/main/names.c> (show do_setInternet2() in C)
* <src/main/internet.c>  (define do_setInternet2() in C).


The problem occurred because the 'scales' package version required by the d3heatmap package/function is old. See [https://github.com/rstudio/d3heatmap/issues/16 this post]. And when I upgraded the 'scales' package, it was ''locked'' by the package was ''imported'' by the ''ggplot2'' package.
Note that: setInternet2(T) becomes default in R 3.2.2. To revert to the previous default use setInternet2(FALSE). See the <doc/NEWS.pdf> file.  If we use setInternet2(F), then it solves the bug of getGEO() error. But it disables the https file download using the download.file() function. In R < 3.2.2, it is also possible to download from https by setIneternet2(T).


==== Unload a package ====
'''R 3.3.0'''
See an example below.
<pre>
<pre>
require(splines)
setInternet2 <- function(use = TRUE) {
detach(package:splines, unload=TRUE)
    if(!is.na(use)) stop("use != NA is defunct")
    NA
}
</pre>
</pre>


==== [http://www.r-pkg.org/ METACRAN] - Search and browse all CRAN/R packages ====
Note that setInternet2.Rd says As from \R 3.3.0 it changes nothing, and only \code{use = NA} is accepted. Also NEWS.Rd says setInternet2() has no effect and will be removed in due course.
* Source code on https://github.com/metacran. The 'PACKAGES' file is updated regularly to Github.
* [https://stat.ethz.ch/pipermail/r-devel/2015-May/thread.html Announcement] on R/mailing list
* Author's homepage on http://gaborcsardi.org/.


==== New R packages as reported by [http://dirk.eddelbuettel.com/cranberries/ CRANberries] ====
== Finite, Infinite and NaN Numbers: is.finite(), is.infinite(), is.nan() ==
http://blog.revolutionanalytics.com/2015/07/mranspackages-spotlight.html
In R, basically all mathematical functions (including basic Arithmetic), are supposed to work properly with +/-, '''Inf''' and '''NaN''' as input or output.


<pre>
See [https://stat.ethz.ch/R-manual/R-devel/library/base/html/is.finite.html ?is.finite].
#----------------------------
# SCRAPE CRANBERRIES FILES TO COUNT NEW PACKAGES AND PLOT
#
library(ggplot2)
# Build a vextor of the directories of interest
year <- c("2013","2014","2015")
month <- c("01","02","03","04","05","06","07","08","09","10","11","12")
span <-c(rep(month,2),month[1:7])
dir <- "http://dirk.eddelbuettel.com/cranberries"


url2013 <- file.path(dir,"2013",month)
[https://datasciencetut.com/how-to-replace-inf-values-with-na-in-r/ How to replace Inf with NA in All or Specific Columns of the Data Frame]
url2014 <- file.path(dir,"2014",month)
url2015 <- file.path(dir,"2015",month[1:7])
url <- c(url2013,url2014,url2015)


# Read each directory and count the new packages
== replace() function ==
new_p <- vector()
* [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/replace replace](vector, index, values)  
for(i in url){
* https://stackoverflow.com/a/11811147
  raw.data <- readLines(i)
  new_p[i] <- length(grep("New package",raw.data,value=TRUE))
}


# Plot
== File/path operations ==
time <- seq(as.Date("2013-01-01"), as.Date("2015-07-01"), by="months")
* list.files(, include.dirs =F, recursive = T, pattern = "\\.csv$", all.files = TRUE)
new_pkgs <- data.frame(time,new_p)
* file.info()
* dir.create()
* file.create()
* file.copy()
* file.exists()
<ul>
<li>'''basename'''() - remove the parent path, '''dirname'''() - returns the part of the path up to but excluding the last path separator
<pre>
> file.path("~", "Downloads")
[1] "~/Downloads"
> dirname(file.path("~", "Downloads"))
[1] "/home/brb"
> basename(file.path("~", "Downloads"))
[1] "Downloads"
</pre>
</li></ul>
* '''path.expand'''("~/.Renviron")  # "/home/brb/.Renviron"
<ul>
<li> '''normalizePath'''() # Express File Paths in Canonical Form
<pre>
> cat(normalizePath(c(R.home(), tempdir())), sep = "\n")
/usr/lib/R
/tmp/RtmpzvDhAe
</pre>
</li>
<li>[https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/system.file system.file()] - Finds the full file names of files in packages etc
<pre>
> system.file("extdata", "ex1.bam", package="Rsamtools")
[1] "/home/brb/R/x86_64-pc-linux-gnu-library/4.0/Rsamtools/extdata/ex1.bam"
</pre>
</li></ul>
* tools::file_path_sans_ext() - [https://stackoverflow.com/a/29114021 remove the file extension] or the sub() function.


ggplot(new_pkgs, aes(time,y=new_p)) +
== read/download/source a file from internet ==
  geom_line() + xlab("") + ylab("Number of new packages") +
=== Simple text file http ===
  geom_smooth(method='lm') + ggtitle("New R packages as reported by CRANberries")  
<pre>
retail <- read.csv("http://robjhyndman.com/data/ausretail.csv",header=FALSE)
</pre>
</pre>


=== R package dependencies ===
=== Zip, RData, gz file and url() function ===
* Package tools' functions package.dependencies(), pkgDepends(), etc are deprecated now, mostly in favor of package_dependencies() which is both more flexible and efficient. See [https://cran.rstudio.com/doc/manuals/r-release/NEWS.html R 3.3.0 News].
<pre>
x <- read.delim(gzfile("filename.txt.gz"), nrows=10)
</pre>
<pre>
con = gzcon(url('http://www.systematicportfolio.com/sit.gz', 'rb'))
source(con)
close(con)
</pre>
Here url() function is like file(),  gzfile(), bzfile(), xzfile(), unz(), pipe(), fifo(), socketConnection(). They are used to create connections. By default, the connection is not opened (except for ‘socketConnection’), but may be opened by setting a non-empty value of argument ‘open’. See ?url.


==== Bioconductor's [http://www.bioconductor.org/packages/release/bioc/html/pkgDepTools.html pkgDepTools] package ====
Another example is [https://stackoverflow.com/a/9548672 Read gzipped csv directly from a url in R]
The is an example of querying the dependencies of the notorious 'lumi' package which often broke the installation script. I am using R 3.2.0 and Bioconductor 3.1.  
<pre>
con <- gzcon(url(paste("http://dumps.wikimedia.org/other/articlefeedback/",
                      "aa_combined-20110321.csv.gz", sep="")))
txt <- readLines(con)
dat <- read.csv(textConnection(txt))
</pre>


The '''getInstallOrder''' function is useful to get a list of all (recursive) dependency packages.
Another example of using url() is
<pre>
<pre>
source("http://bioconductor.org/biocLite.R")
load(url("http:/www.example.com/example.RData"))
if (!require(pkgDepTools)) {
</pre>
  biocLite("pkgDepTools", ask = FALSE)
  library(pkgDepTools)
}
MkPlot <- FALSE


library(BiocInstaller)
This does not work with load(), dget(), read.table() for files on '''OneDrive'''. In fact, I cannot use wget with shared files from OneDrive. The following trick works: [https://mangolassi.it/topic/19276/how-to-configure-a-onedrive-file-for-use-with-wget How to configure a OneDrive file for use with wget].
biocUrl <- biocinstallRepos()["BioCsoft"]
biocDeps <- makeDepGraph(biocUrl, type="source", dosize=FALSE) # pkgDepTools defines its makeDepGraph()


PKG <- "lumi"
'''Dropbox''' is easy and works for load(), wget, ...
if (MkPlot) {
  if (!require(Biobase)) {
    biocLite("Biobase", ask = FALSE)
    library(Biobase)
  }
  if (!require(Rgraphviz))  {
    biocLite("Rgraphviz", ask = FALSE)
    library(Rgraphviz)
  }
  categoryNodes <- c(PKG, names(acc(biocDeps, PKG)[[1]])) 
  categoryGraph <- subGraph(categoryNodes, biocDeps)
  nn <- makeNodeAttrs(categoryGraph, shape="ellipse")
  plot(categoryGraph, nodeAttrs=nn)  # Complete but plot is too complicated & font is too small.
}


system.time(allDeps <- makeDepGraph(biocinstallRepos(), type="source",
[https://stackoverflow.com/a/46875562 R download .RData] or [https://stackoverflow.com/a/56670130 Directly loading .RData from github] from Github.
                          keep.builtin=TRUE, dosize=FALSE)) # takes a little while
#    user  system elapsed
# 175.737  10.994 186.875
# Warning messages:
# 1: In .local(from, to, graph) : edges replaced: ‘SNPRelate|gdsfmt’
# 2: In .local(from, to, graph) :
#  edges replaced: ‘RCurl|methods’, ‘NA|bitops’


# When needed.only=TRUE, only those dependencies not currently installed are included in the list.
=== zip function ===
x1 <- sort(getInstallOrder(PKG, allDeps, needed.only=TRUE)$packages); x1
This will include 'hallmarkFiles' root folder in the files inside zip.
[1] "affy"                              "affyio"                         
<pre>
[3] "annotate"                          "AnnotationDbi"                   
zip(zipfile = 'myFile.zip',  
[5] "base64"                            "beanplot"                       
     files = dir('hallmarkFiles', full.names = TRUE))
[7] "Biobase"                          "BiocParallel"                   
[9] "biomaRt"                          "Biostrings"                     
[11] "bitops"                            "bumphunter"                     
[13] "colorspace"                        "DBI"                             
[15] "dichromat"                        "digest"                         
[17] "doRNG"                            "FDb.InfiniumMethylation.hg19"      
[19] "foreach"                          "futile.logger"                   
[21] "futile.options"                    "genefilter"                     
[23] "GenomeInfoDb"                      "GenomicAlignments"               
[25] "GenomicFeatures"                  "GenomicRanges"                   
[27] "GEOquery"                          "ggplot2"                         
[29] "gtable"                            "illuminaio"                     
[31] "IRanges"                          "iterators"                       
[33] "labeling"                          "lambda.r"                       
[35] "limma"                            "locfit"                         
[37] "lumi"                              "magrittr"                       
[39] "matrixStats"                      "mclust"                         
[41] "methylumi"                        "minfi"                           
[43] "multtest"                          "munsell"                         
[45] "nleqslv"                          "nor1mix"                         
[47] "org.Hs.eg.db"                      "pkgmaker"                       
[49] "plyr"                              "preprocessCore"                 
[51] "proto"                            "quadprog"                       
[53] "RColorBrewer"                      "Rcpp"                           
[55] "RCurl"                            "registry"                       
[57] "reshape"                          "reshape2"                       
[59] "rngtools"                          "Rsamtools"                       
[61] "RSQLite"                          "rtracklayer"                     
[63] "S4Vectors"                        "scales"                         
[65] "siggenes"                          "snow"                           
[67] "stringi"                          "stringr"                         
[69] "TxDb.Hsapiens.UCSC.hg19.knownGene" "XML"                             
[71] "xtable"                            "XVector"                         
[73] "zlibbioc"                       
 
# When needed.only=FALSE the complete list of dependencies is given regardless of the set of currently installed packages.
x2 <- sort(getInstallOrder(PKG, allDeps, needed.only=FALSE)$packages); x2
[1] "affy"                              "affyio"                            "annotate"                       
[4] "AnnotationDbi"                    "base64"                            "beanplot"                       
[7] "Biobase"                          "BiocGenerics"                      "BiocInstaller"                   
[10] "BiocParallel"                      "biomaRt"                          "Biostrings"                     
[13] "bitops"                            "bumphunter"                        "codetools"                       
[16] "colorspace"                        "DBI"                              "dichromat"                       
[19] "digest"                            "doRNG"                            "FDb.InfiniumMethylation.hg19"   
[22] "foreach"                          "futile.logger"                    "futile.options"                 
[25] "genefilter"                        "GenomeInfoDb"                      "GenomicAlignments"               
[28] "GenomicFeatures"                  "GenomicRanges"                    "GEOquery"                       
[31] "ggplot2"                          "graphics"                          "grDevices"                       
[34] "grid"                              "gtable"                            "illuminaio"                     
[37] "IRanges"                          "iterators"                        "KernSmooth"                     
[40] "labeling"                          "lambda.r"                          "lattice"                         
[43] "limma"                            "locfit"                            "lumi"                           
[46] "magrittr"                          "MASS"                              "Matrix"                         
[49] "matrixStats"                      "mclust"                            "methods"                         
[52] "methylumi"                        "mgcv"                              "minfi"                           
[55] "multtest"                          "munsell"                          "nleqslv"                         
[58] "nlme"                              "nor1mix"                          "org.Hs.eg.db"                   
[61] "parallel"                          "pkgmaker"                          "plyr"                           
[64] "preprocessCore"                    "proto"                            "quadprog"                       
[67] "RColorBrewer"                      "Rcpp"                              "RCurl"                           
[70] "registry"                          "reshape"                          "reshape2"                       
[73] "rngtools"                          "Rsamtools"                        "RSQLite"                         
[76] "rtracklayer"                      "S4Vectors"                        "scales"                         
[79] "siggenes"                          "snow"                              "splines"                         
[82] "stats"                            "stats4"                            "stringi"                         
[85] "stringr"                          "survival"                          "tools"                           
[88] "TxDb.Hsapiens.UCSC.hg19.knownGene" "utils"                            "XML"                             
[91] "xtable"                            "XVector"                          "zlibbioc"


> sort(setdiff(x2, x1)) # Not all R's base packages are included; e.g. 'base', 'boot', ...
# Verify/view the files. 'list = TRUE' won't extract
[1] "BiocGenerics"  "BiocInstaller" "codetools"    "graphics"      "grDevices"   
unzip('testZip.zip', list = TRUE)
[6] "grid"          "KernSmooth"    "lattice"      "MASS"          "Matrix"     
[11] "methods"      "mgcv"          "nlme"          "parallel"      "splines"     
[16] "stats"        "stats4"        "survival"      "tools"        "utils" 
</pre>
</pre>
[[File:Lumi rgraphviz.svg|200px]]


==== [http://cran.r-project.org/web/packages/miniCRAN/ miniCRAN package]  ====
=== [http://cran.r-project.org/web/packages/downloader/index.html downloader] package ===
'''miniCRAN''' package can be used to identify package dependencies or create a local CRAN repository. It can be used on repositories other than CRAN, such as Bioconductor.
This package provides a wrapper for the download.file function, making it possible to download files over https on Windows, Mac OS X, and other Unix-like platforms. The RCurl package provides this functionality (and much more) but can be difficult to install because it must be compiled with external dependencies. This package has no external dependencies, so it is much easier to install.


* http://blog.revolutionanalytics.com/2014/07/dependencies-of-popular-r-packages.html
=== Google drive file based on https using [http://www.omegahat.org/RCurl/FAQ.html RCurl] package ===
* http://www.r-bloggers.com/introducing-minicran-an-r-package-to-create-a-private-cran-repository/
{{Pre}}
* http://www.magesblog.com/2014/09/managing-r-package-dependencies.html
require(RCurl)
* [http://blog.revolutionanalytics.com/2015/10/using-minicran-in-azure-ml.html Using miniCRAN in Azure ML]
myCsv <- getURL("https://docs.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0AkuuKBh0jM2TdGppUFFxcEdoUklCQlJhM2kweGpoUUE&single=true&gid=0&output=csv")
* [http://www.mango-solutions.com/wp/2016/01/minicran-developing-internal-cran-repositories/ developing internal CRAN Repositories]
read.csv(textConnection(myCsv))
</pre>


Before we go into R, we need to install some packages from Ubuntu terminal. See [[R#Ubuntu.2FDebian_2|here]].
=== Google sheet file using [https://github.com/jennybc/googlesheets googlesheets] package ===
<syntaxhighlight lang='rsplus'>
[http://www.opiniomics.org/reading-data-from-google-sheets-into-r/ Reading data from google sheets into R]
# Consider glmnet package (today is 4/29/2015)
# Version: 2.0-2
# Depends: Matrix (≥ 1.0-6), utils, foreach
# Suggests: survival, knitr, lars
if (!require("miniCRAN"))  {
  install.packages("miniCRAN", dependencies = TRUE, repos="http://cran.rstudio.com") # include 'igraph' in Suggests.
  library(miniCRAN)
}
if (!"igraph" %in% installed.packages()[,1]) install.packages("igraph")


tags <- "glmnet"
=== Github files https using RCurl package ===
pkgDep(tags, suggests=TRUE, enhances=TRUE) # same as pkgDep(tags)
* http://support.rstudio.org/help/kb/faq/configuring-r-to-use-an-http-proxy
#  [1] "glmnet"    "Matrix"    "foreach"  "codetools" "iterators" "lattice"  "evaluate"  "digest" 
* http://tonybreyal.wordpress.com/2011/11/24/source_https-sourcing-an-r-script-from-github/
#  [9] "formatR"  "highr"    "markdown"  "stringr"  "yaml"      "mime"      "survival"  "knitr"   
<pre>
# [17] "lars"  
x = getURL("https://gist.github.com/arraytools/6671098/raw/c4cb0ca6fe78054da8dbe253a05f7046270d5693/GeneIDs.txt",
 
            ssl.verifypeer = FALSE)
dg <- makeDepGraph(tags, suggests=TRUE, enhances=TRUE) # miniCRAN defines its makeDepGraph()
read.table(text=x)
plot(dg, legendPosition = c(-1, 1), vertex.size=20)
</pre>
</syntaxhighlight>
* [http://cran.r-project.org/web/packages/gistr/index.html gistr] package


[[File:MiniCRAN dep.svg|300px]] [[File:pkgDepTools dep.svg|300px]]
== data summary table ==
[[File:Glmnet dep.svg|300px]]
=== summarytools: create summary tables for vectors and data frames ===
https://github.com/dcomtois/summarytools. R Package for quickly and neatly summarizing vectors and data frames.


We can also display the dependence for a package from the [http://cran.r-project.org/web/packages/miniCRAN/vignettes/miniCRAN-non-CRAN-repos.html Bioconductor] repository.
=== skimr: A frictionless, pipeable approach to dealing with summary statistics ===
<syntaxhighlight lang='rsplus'>
[https://ropensci.org/blog/2017/07/11/skimr/ skimr for useful and tidy summary statistics]
tags <- "DESeq2"
# Depends S4Vectors, IRanges, GenomicRanges, Rcpp (>= 0.10.1), RcppArmadillo (>= 0.3.4.4)
# Imports BiocGenerics(>= 0.7.5), Biobase, BiocParallel, genefilter, methods, locfit, geneplotter, ggplot2, Hmisc
# Suggests RUnit, gplots, knitr, RColorBrewer, BiocStyle, airway,\npasilla (>= 0.2.10), DESeq, vsn
# LinkingTo    Rcpp, RcppArmadillo
index <- function(url, type="source", filters=NULL, head=5, cols=c("Package", "Version")){
  contribUrl <- contrib.url(url, type=type)
  available.packages(contribUrl, type=type, filters=filters)
}


bioc <- local({
=== modelsummary ===
  env <- new.env()
[https://cloud.r-project.org/web/packages/modelsummary/index.html modelsummary]: Summary Tables and Plots for Statistical Models and Data: Beautiful, Customizable, and Publication-Ready
  on.exit(rm(env))
  evalq(source("http://bioconductor.org/biocLite.R", local=TRUE), env)
  biocinstallRepos() # return URLs
})


bioc
=== broom ===
#                                               BioCsoft
[[Tidyverse#broom|Tidyverse->broom]]
#            "http://bioconductor.org/packages/3.0/bioc"
#                                                BioCann
# "http://bioconductor.org/packages/3.0/data/annotation"
#                                                BioCexp
# "http://bioconductor.org/packages/3.0/data/experiment"
#                                              BioCextra
#          "http://bioconductor.org/packages/3.0/extra"
#                                                  CRAN
#                                "http://cran.fhcrc.org"
#                                              CRANextra
#                  "http://www.stats.ox.ac.uk/pub/RWin"
str(index(bioc["BioCsoft"])) # similar to cranJuly2014 object


system.time(dg <- makeDepGraph(tags, suggests=TRUE, enhances=TRUE, availPkgs = index(bioc["BioCsoft"]))) # Very quick!
=== Create publication tables using '''tables''' package ===
plot(dg, legendPosition = c(-1, 1), vertex.size=20)
See p13 for example at [http://www.ianwatson.com.au/stata/tabout_tutorial.pdf#page=13 here]
</syntaxhighlight>
[[File:deseq2 dep.svg|300px]] [[File:Lumi dep.svg|300px]]


The dependencies of [http://www.bioconductor.org/packages/release/bioc/html/GenomicFeatures.html GenomicFeature] and [http://www.bioconductor.org/packages/release/bioc/html/GenomicAlignments.html GenomicAlignments] are more complicated. So we turn the 'suggests' option to FALSE.
R's [http://cran.r-project.org/web/packages/tables/index.html tables] packages is the best solution. For example,
<syntaxhighlight lang='rsplus'>
{{Pre}}
tags <- "GenomicAlignments"
> library(tables)
dg <- makeDepGraph(tags, suggests=FALSE, enhances=FALSE, availPkgs = index(bioc["BioCsoft"]))
> tabular( (Species + 1) ~ (n=1) + Format(digits=2)*
plot(dg, legendPosition = c(-1, 1), vertex.size=20)
+          (Sepal.Length + Sepal.Width)*(mean + sd), data=iris )
</syntaxhighlight>
                                                 
[[File:Genomicfeature dep dep.svg|300px]] [[File:Genomicalignments dep.svg|300px]]
                Sepal.Length      Sepal.Width   
 
Species    n  mean        sd  mean        sd 
==== [http://mran.revolutionanalytics.com/ MRAN] (CRAN only)====
setosa      50 5.01        0.35 3.43        0.38
* http://blog.revolutionanalytics.com/2014/10/explore-r-package-connections-at-mran.html
versicolor  50 5.94        0.52 2.77        0.31
 
virginica  50 6.59        0.64 2.97        0.32
==== Reverse dependence ====
All        150 5.84        0.83 3.06        0.44
* http://romainfrancois.blog.free.fr/index.php?post/2011/10/30/Rcpp-reverse-dependency-graph
> str(iris)
 
'data.frame':   150 obs. of 5 variables:
=== Create a new R package, namespace, documentation ===
$ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
* http://cran.r-project.org/doc/contrib/Leisch-CreatingPackages.pdf (highly recommend)
$ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
* https://stat.ethz.ch/pipermail/r-devel/2013-July/066975.html
$ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
* [http://stackoverflow.com/questions/7283134/what-is-the-benefit-of-import-in-a-namespace-in-r/7283511#7283511 Benefit of import in a namespace]
$ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
* This youtube [http://www.youtube.com/watch?v=jGeCCxdZsDQ video] from Tyler Rinker teaches how to use RStudio to develop an R package and also use Git to do version control. Very useful!
$ Species    : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
* [https://github.com/jtleek/rpackages Developing R packages] by Jeff Leek in Johns Hopkins University.
</pre>
* [http://r-pkgs.had.co.nz/ R packages] book by Hadley Wickham.
and
* [http://kbroman.org/pkg_primer/ R package primer] a minimal tutorial from Karl Broman].
<pre>
 
# This example shows some of the less common options       
==== R package depends vs imports ====
> Sex <- factor(sample(c("Male", "Female"), 100, rep=TRUE))
* http://stackoverflow.com/questions/8637993/better-explanation-of-when-to-use-imports-depends
> Status <- factor(sample(c("low", "medium", "high"), 100, rep=TRUE))
* http://stackoverflow.com/questions/9893791/imports-and-depends
> z <- rnorm(100)+5
* https://stat.ethz.ch/pipermail/r-devel/2013-August/067082.html
> fmt <- function(x) {
 
  s <- format(x, digits=2)
In the namespace era Depends is never really needed. All modern packages have no technical need for Depends anymore. Loosely speaking the only purpose of Depends today is to expose other package's functions to the user without re-exporting them.
  even <- ((1:length(s)) %% 2) == 0
 
  s[even] <- sprintf("(%s)", s[even])
load = functions exported in myPkg are available to interested parties as myPkg::foo or via direct imports - essentially this means the package can now be used
  s
 
}
attach = the namespace (and thus all exported functions) is attached to the search path - the only effect is that you have now added the exported functions to the global pool of functions - sort of like dumping them in the workspace (for all practical purposes, not technically)
> tabular( Justify(c)*Heading()*z*Sex*Heading(Statistic)*Format(fmt())*(mean+sd) ~ Status )
 
                  Status             
import a function into a package = make sure that this function works in my package regardless of the search path (so I can write fn1 instead of pkg1::fn1 and still know it will come from pkg1 and not someone's workspace or other package that chose the same name)
Sex    Statistic high  low    medium
 
Female mean      4.88  4.96  5.17
------------------------------------------------------------------------
        sd        (1.20) (0.82) (1.35)
* https://stat.ethz.ch/pipermail/r-devel/2013-September/067451.html
Male  mean      4.45  4.31  5.05
        sd        (1.01) (0.93) (0.75)
</pre>


The distinction is between "loading" and "attaching" a package. Loading
=== fgsea example ===
it (which would be done if you had MASS::loglm, or imported it)
[http://www.bioconductor.org/packages/release/bioc/vignettes/fgsea/inst/doc/fgsea-tutorial.html  vignette] & [https://github.com/ctlab/fgsea/blob/master/R/plot.R#L28 source code]
guarantees that the package is initialized and in memory, but doesn't
make it visible to the user without the explicit MASS:: prefix.
Attaching it first loads it, then modifies the user's search list so the
user can see it.


Loading is less intrusive, so it's preferred over attaching.  Both
=== (archived) ClinReport: Statistical Reporting in Clinical Trials ===
library() and require() would attach it.
https://cran.r-project.org/web/packages/ClinReport/index.html


==== Create R package with devtools and roxygen2 ====
== Append figures to PDF files ==
A useful [http://thepoliticalmethodologist.com/2014/08/14/building-and-maintaining-r-packages-with-devtools-and-roxygen2/ post] by Jacob Montgomery. Do watch the [https://www.youtube.com/watch?v=9PyQlbAEujY#t=19 youtube video] there.
[https://stackoverflow.com/a/13274272 How to append a plot to an existing pdf file]. Hint: use the recordPlot() function.


The process requires 3 components: RStudio software, devtools and [http://cran.r-project.org/web/packages/roxygen2/index.html roxygen2] (creating documentation from R code) packages.
== Save base graphics as pseudo-objects ==
[https://www.andrewheiss.com/blog/2016/12/08/save-base-graphics-as-pseudo-objects-in-r/ Save base graphics as pseudo-objects in R]. Note there are some cons with this approach.
<pre>
pdf(NULL)
dev.control(displaylist="enable")
plot(df$x, df$y)
text(40, 0, "Random")
text(60, 2, "Text")
lines(stats::lowess(df$x, df$y))
p1.base <- recordPlot()
invisible(dev.off())


==== Minimal R package for submission ====
# Display the saved plot
https://stat.ethz.ch/pipermail/r-devel/2013-August/067257.html and [http://cran.r-project.org/web/packages/policies.html CRAN Repository Policy].
grid::grid.newpage()
p1.base
</pre>


==== [https://travis-ci.org/ Travis-CI] ====
== Extracting tables from PDFs ==  
* [http://juliasilge.com/blog/Beginners-Guide-to-Travis/ A Beginner's Guide to Travis-CI]
<ul>
* [http://r-pkgs.had.co.nz/tests.html testhat] package
<li>[http://datascienceplus.com/extracting-tables-from-pdfs-in-r-using-the-tabulizer-package/ extracting Tables from PDFs in R] using Tabulizer. This needs the [https://cran.r-project.org/web/packages/rJava/index.html rJava] package. Linux works fine. Some issue came out on my macOS 10.12 Sierra. '''Library not loaded: /Library/Java/JavaVirtualMachines/jdk-9.jdk/Contents/Home/lib/server/libjvm.dylib. Referenced from: /Users/XXXXXXX/Library/R/3.5/library/rJava/libs/rJava.so'''.
</li>
<li>
[https://docs.ropensci.org/pdftools/ pdftools] - Text Extraction, Rendering and Converting of PDF Documents. [https://ropensci.org/technotes/2018/12/14/pdftools-20/ pdf_text() and pdf_data()] functions.
{{Pre}}
library(pdftools)
pdf_file <- "https://github.com/ropensci/tabulizer/raw/master/inst/examples/data.pdf"
txt <- pdf_text(pdf_file) # length = number of pages
# Suppose the table we are interested in is on page 1
cat(txt[1]) # Good but not in a data frame format


==== Submit packages to cran ====
pdf_data(pdf_file)[[1]]  # data frame/tibble format
* http://f.briatte.org/r/submitting-packages-to-cran
</pre>
* https://rmhogervorst.github.io/cleancode/blog/2016/07/09/submtting-to-cran-first-experience.html
However, it seems it does not work on [http://www.bloodjournal.org/content/109/8/3177/tab-figures-only Table S6]. Tabulizer package is better at this case.


=== Build R package faster using multicore ===
This is another example. [https://mp.weixin.qq.com/s?__biz=MzAxMDkxODM1Ng==&mid=2247490327&idx=1&sn=cca7d4423426318e0c23adb098cf0ad7&chksm=9b485bacac3fd2ba2196b380c59b5eab9d29795d3334b040f50a2fa58124ec6e3be9472829e0&scene=21#wechat_redirect 神技能-自动化批量从PDF里面提取表格]
http://www.rexamine.com/2015/07/speeding-up-r-package-installation-process/
</li>
<li>[https://www.linuxuprising.com/2019/05/how-to-convert-pdf-to-text-on-linux-gui.html?m=1 How To Convert PDF To Text On Linux (GUI And Command Line)]. It works when I tested my PDF file.
{{Pre}}
sudo apt install poppler-utils
pdftotext -layout input.pdf output.txt
pdftotext -layout -f 3 -l 4 input.pdf output.txt # from page 3 to 4.
</pre>
</li>
<li>[https://www.adobe.com/acrobat/how-to/pdf-to-excel-xlsx-converter.html Convert PDF files into Excel spreadsheets] using Adobe Acrobat. See [https://helpx.adobe.com/acrobat/how-to/extract-pages-from-pdf.html How to extract pages from a PDF]. Note the PDF file should not be opened by Excel since it is binary format Excel can't recognize.
<li>I found it is easier to use copy the column (it works) from PDF and paste them to Excel </li>
<li>[https://www.r-bloggers.com/2024/04/tabulapdf-extract-tables-from-pdf-documents/ tabulapdf: Extract Tables from PDF Documents]
</ul>


The idea is edit the '''/lib64/R/etc/Renviron''' file (where /lib64/R/etc/ is the result to a call to the R.home() function in R) and set:
== Print tables ==
<pre>
MAKE='make -j 8' # submit 8 jobs at once
</pre>
Then build R package as regular, for example,
<pre>
$ time R CMD INSTALL ~/R/stringi --preclean --configure-args='--disable-pkg-config'
</pre>


=== Detect number of running R instances in Windows ===
=== addmargins() ===
* http://stackoverflow.com/questions/15935931/detect-number-of-running-r-instances-in-windows-within-r
* [https://www.rdocumentation.org/packages/stats/versions/3.5.1/topics/addmargins addmargins]. Puts Arbitrary Margins On Multidimensional Tables Or Arrays.
<pre>
* [https://datasciencetut.com/how-to-put-margins-on-tables-or-arrays-in-r/ How to put margins on tables or arrays in R?]
C:\Program Files\R>tasklist /FI "IMAGENAME eq Rscript.exe"
INFO: No tasks are running which match the specified criteria.


C:\Program Files\R>tasklist /FI "IMAGENAME eq Rgui.exe"
=== tableone ===
* https://cran.r-project.org/web/packages/tableone/
* [https://datascienceplus.com/table-1-and-the-characteristics-of-study-population/ Table 1 and the Characteristics of Study Population]
* [https://www.jianshu.com/p/e76f2b708d45 如何快速绘制论文的表1(基本特征三线表)?]
* See Table 1 from [https://boiled-data.github.io/ClassificationDiabetes.html Tidymodels Machine Learning: Diabetes Classification]


Image Name                    PID Session Name        Session#    Mem Usage
=== Some examples ===
========================= ======== ================ =========== ============
Cox models
Rgui.exe                      1096 Console                    1    44,712 K
* [https://aacrjournals.org/clincancerres/article/27/12/3383/671420/Integrative-Genomic-Analysis-of-Gemcitabine Integrative Genomic Analysis of Gemcitabine Resistance in Pancreatic Cancer by Patient-derived Xenograft Models]
 
C:\Program Files\R>tasklist /FI "IMAGENAME eq Rserve.exe"


Image Name                    PID Session Name        Session#    Mem Usage
=== finalfit package ===
========================= ======== ================ =========== ============
* https://cran.r-project.org/web/packages/finalfit/index.html. Lots of vignettes.
Rserve.exe                    6108 Console                    1    381,796 K
** [https://cran.r-project.org/web/packages/finalfit/vignettes/survival.html Survival]. It fits both univariate and multivariate regressions and reports the results for both of them.
</pre>
* [https://finalfit.org/index.html summary_factorlist()] from the finalfit package.
In R, we can use
* [https://www.r-bloggers.com/2018/05/elegant-regression-results-tables-and-plots-in-r-the-finalfit-package/ Elegant regression results tables and plots in R: the finalfit package]
<pre>
> system('tasklist /FI "IMAGENAME eq Rgui.exe" ', intern = TRUE)
[1] ""                                                                           
[2] "Image Name                    PID Session Name        Session#    Mem Usage"
[3] "========================= ======== ================ =========== ============"
[4] "Rgui.exe                      1096 Console                    1    44,804 K"


> length(system('tasklist /FI "IMAGENAME eq Rgui.exe" ', intern = TRUE))-3
=== table1 ===
</pre>
* https://cran.r-project.org/web/packages/table1/
* [https://www.rdatagen.net/post/2023-09-26-nice-looking-table-1-with-standardized-mean-difference/ Creating a nice looking Table 1 with standardized mean differences (SMD)]. SMD is the difference in group means divided by the pooled standard deviation (and is defined differently for categorical measures). Note that the pooled standard deviation defined here is different from we see on the '''[[T-test#Two_sample_test_assuming_equal_variance|t.test]]''' when we assume equivalent variance in two samples.


=== Editor ===
=== gtsummary ===
http://en.wikipedia.org/wiki/R_(programming_language)#Editors_and_IDEs
* [https://education.rstudio.com/blog/2020/07/gtsummary/ Presentation-Ready Summary Tables with gtsummary]
* [https://www.danieldsjoberg.com/gtsummary/ gtsummary] & on [https://cloud.r-project.org/web/packages/gtsummary/index.html CRAN]
** [https://www.danieldsjoberg.com/gtsummary/articles/tbl_summary.html tbl_summary()]. The output is in the "Viewer" window.
* An example: [https://boiled-data.github.io/ClassificationDiabetes.html Tidymodels Machine Learning: Diabetes Classification]. The table is saved in a png file. The column variable is response.


* Emacs + ESS. The ESS is useful in the case I want to tidy R code (the tidy_source() function in the formatR package sometimes gives errors; eg when I tested it on an R file like <GetComparisonResults.R> from BRB-ArrayTools v4.4 stable).
=== gt* ===
* [http://www.rstudio.com/ Rstudio] - editor/R terminal/R graphics/file browser/package manager. The new version (0.98) also provides a new feature for debugging step-by-step.
* [https://cran.r-project.org/web/packages/gt/index.html gt]: Easily Create Presentation-Ready Display Tables
* [http://www.geany.org/ geany] - I like the feature that it shows defined functions on the side panel even for R code. RStudio can also do this (see the bottom of the code panel).
* [https://www.r-bloggers.com/2024/02/introduction-to-clinical-tables-with-the-gt-package/ Introduction to Clinical Tables with the {gt} Package]
* [http://rgedit.sourceforge.net/ Rgedit] which includes a feature of splitting screen into two panes and run R in the bottom panel. See [http://www.stattler.com/article/using-gedit-or-rgedit-r here].
* [https://www.youtube.com/watch?v=qFOFMed18T4 Add any Plot to your {gt} table]
* Komodo IDE with browser preview http://www.youtube.com/watch?v=wv89OOw9roI at 4:06 and http://docs.activestate.com/komodo/4.4/editor.html


=== GUI for Data Analysis ===
=== dplyr ===
https://stackoverflow.com/a/34587522. The output includes counts and proportions in a publication like fashion.


==== Rcmdr ====
=== tables::tabular() ===
http://cran.r-project.org/web/packages/Rcmdr/index.html


==== Deducer ====
=== gmodels::CrossTable() ===
http://cran.r-project.org/web/packages/Deducer/index.html
https://www.statmethods.net/stats/frequencies.html


=== Scope ===
=== base::prop.table(x, margin) ===
See [http://cran.r-project.org/doc/manuals/R-intro.html#Assignment-within-functions Assignments within functions] in the '''An Introduction to R''' manual.
[http://developer.r-project.org/blosxom.cgi/R-devel/2020/02/13#n2020-02-13 New function ‘proportions()’ and ‘marginSums()’. These should replace the unfortunately named ‘prop.table()’ and ‘margin.table()’.] for R 4.0.0.
<pre>
R> m <- matrix(1:4, 2)
R> prop.table(m, 1) # row percentage
          [,1]      [,2]
[1,] 0.2500000 0.7500000
[2,] 0.3333333 0.6666667
R> prop.table(m, 2) # column percentage
          [,1]      [,2]
[1,] 0.3333333 0.4285714
[2,] 0.6666667 0.5714286
</pre>


'''Note that any ordinary assignments done within the function are local and temporary and are lost after exit from the function.'''
=== stats::xtabs() ===


Example 1.
=== stats::ftable() ===
<pre>
{{Pre}}
> ttt <- data.frame(type=letters[1:5], JpnTest=rep("999", 5), stringsAsFactors = F)
> ftable(Titanic, row.vars = 1:3)
> ttt
                  Survived  No Yes
   type JpnTest
Class Sex    Age                 
1   a    999
1st  Male  Child            0   5
2    b    999
            Adult          118  57
3    c    999
      Female Child            0  1
4    d    999
            Adult            4 140
5    e    999
2nd  Male  Child            0  11
> jpntest <- function() { ttt$JpnTest[1] ="N5"; print(ttt)}
            Adult          154  14
> jpntest()
      Female Child            0  13
   type JpnTest
            Adult          13  80
1    a      N5
3rd  Male  Child          35  13
2    b    999
            Adult          387  75
3    c    999
      Female Child          17  14
4   d    999
            Adult          89  76
5    e    999
Crew  Male  Child            0  0
> ttt
            Adult          670 192
   type JpnTest
      Female Child            0  0
1    a    999
            Adult            3  20
2    b    999
> ftable(Titanic, row.vars = 1:2, col.vars = "Survived")
3   c    999
            Survived  No Yes
4    d    999
Class Sex                   
5    e    999
1st   Male            118  62
</pre>
      Female            4 141
 
2nd  Male            154  25
Example 2. [http://stackoverflow.com/questions/1236620/global-variables-in-r How can we set global variables inside a function?] The answer is to use the "<<-" operator or '''assign(, , envir = .GlobalEnv)''' function.
      Female          13  93
 
3rd   Male            422  88
Other resource: [http://adv-r.had.co.nz/Functions.html Advanced R] by Hadley Wickham.
      Female          106  90
 
Crew  Male            670 192
=== Speedup R code ===
      Female            3 20
* [http://datascienceplus.com/strategies-to-speedup-r-code/ Strategies to speedup R code] from DataScience+
> ftable(Titanic, row.vars = 2:1, col.vars = "Survived")
 
            Survived  No Yes
=== Vectorization ===
Sex    Class               
http://www.noamross.net/blog/2014/4/16/vectorization-in-r--why.html
Male  1st            118  62
 
      2nd            154  25
==== Mean of duplicated rows ====
      3rd            422  88
* rowsum()
      Crew          670 192
* [http://stackoverflow.com/questions/7881660/finding-the-mean-of-all-duplicates use ave() and unique()]
Female 1st              4 141
* [http://stackoverflow.com/questions/17383635/average-between-duplicated-rows-in-r data.table package]
      2nd            13  93
* [http://stackoverflow.com/questions/10180132/consolidate-duplicate-rows plyr package]
      3rd            106  90
* [http://www.statmethods.net/management/aggregate.html aggregate()] function. Too slow! http://slowkow.com/2015/01/28/data-table-aggregate/. [http://www.win-vector.com/blog/2015/10/dont-use-statsaggregate/ Don't use aggregate] post.
      Crew            3  20
<pre>
> str(Titanic)
> attach(mtcars)
table [1:4, 1:2, 1:2, 1:2] 0 0 35 0 0 0 17 0 118 154 ...
> head(mtcars)
- attr(*, "dimnames")=List of 4
                  mpg cyl disp hp drat    wt qsec vs am gear carb
  ..$ Class  : chr [1:4] "1st" "2nd" "3rd" "Crew"
Mazda RX4        21.0   6 160 110 3.90 2.620 16.46 0  1   4    4
  ..$ Sex    : chr [1:2] "Male" "Female"
Mazda RX4 Wag     21.6 160 110 3.90 2.875 17.02  0  1   4    4
  ..$ Age    : chr [1:2] "Child" "Adult"
Datsun 710        22.4 108 93 3.85 2.320 18.61 1  1   4    1
  ..$ Survived: chr [1:2] "No" "Yes"
Hornet 4 Drive    21.6 258 110 3.08 3.215 19.44 1  0   3    1
> x <- ftable(mtcars[c("cyl", "vs", "am", "gear")])
Hornet Sportabout 18.7  8 360 175 3.15 3.440 17.02 0  0    3   2
> x
Valiant          18.1   225 105 2.76 3.460 20.22 1 0    3    1
          gear  3 4 5
> aggdata <-aggregate(mtcars, by=list(cyl,vs),  
cyl vs am            
+  FUN=mean, na.rm=TRUE)
4  0  0        0  0
> print(aggdata)
      1        0 0  1
  Group.1 Group.2      mpg cyl  disp      hp     drat      wt     qsec vs
     1  0        1  2  0
1       4      0 26.00000  4 120.30 91.0000 4.430000 2.140000 16.70000 0
      1        0 6  1
2      6      0 20.56667   6 155.00 131.6667 3.806667 2.755000 16.32667 0
6   0  0        0  0  0
3      8      0 15.10000  8 353.10 209.2143 3.229286 3.999214 16.77214 0
      1        0 2 1
4       4      1 26.73000  4 103.62 81.8000 4.035000 2.300300 19.38100 1
    1 0       2  2 0
5       6      1 19.12500  6 204.55 115.2500 3.420000 3.388750 19.21500 1
      1       0  0  0
        am    gear    carb
0 0      12 0 0
1 1.0000000 5.000000 2.000000
      1       0  0 2
2 1.0000000 4.333333 4.666667
    1 0        0  0  0
3 0.1428571 3.285714 3.500000
      1       0  0  0
4 0.7000000 4.000000 1.500000
> ftable(x, row.vars = c(2, 4))
5 0.0000000 3.500000 2.500000
        cyl  4     6    8 
> detach(mtcars)
        am   0  1 0 1  0 1
vs gear                     
0 3         0  0  0 0 12 0
   4        0  0  0  2  0  0
   5        0  1  0  1  0  2
1 3        1  0  2  0  0  0
  4        2  6  2  0  0 0
   5        0  1 0  0  0  0
>
> ## Start with expressions, use table()'s "dnn" to change labels
> ftable(mtcars$cyl, mtcars$vs, mtcars$am, mtcars$gear, row.vars = c(2, 4),
        dnn = c("Cylinders", "V/S", "Transmission", "Gears"))
 
          Cylinders    4     6    
          Transmission  0  1 1 0 1
V/S Gears                             
0  3                   0  0 0 0 12 0
    4                   0  0  0 0  0
    5                   0  1 0 1 0  2
1   3                  1 2 0  0  0
    4                  2  6  2 0  0  0
    5                  0 1 0  0  0  0
</pre>
</pre>


=== Apply family ===
== tracemem, data type, copy ==
Vectorize, aggregate, apply, by, eapply, lapply, mapply, rapply, replicate, scale, sapply, split, tapply, and vapply. Check out [http://people.stern.nyu.edu/ylin/r_apply_family.html this].
[http://stackoverflow.com/questions/18359940/r-programming-vector-a1-2-avoid-copying-the-whole-vector/18361181#18361181 How to avoid copying a long vector]


* apply – Apply a Functions Over Array Margins
== Tell if the current R is running in 32-bit or 64-bit mode ==
* sapply – Apply a Function over a List or Vector
<pre>
* lapply – Apply a Function over a List or Vector
8 * .Machine$sizeof.pointer
* tapply – Apply a Function Over a "Ragged" Array
</pre>
* mapply – Multivariate version of sapply
where '''sizeof.pointer''' returns the number of *bytes* in a C SEXP type and '8' means number of bits per byte.
* rapply – A recursive version of lapply
* eapply – Apply a Function over values in an environment
 
However, apply is just a wrap of a loop. The performance is not better than a for loop. See
* http://tolstoy.newcastle.edu.au/R/help/06/05/27255.html (answered by Brian Ripley)
* https://stat.ethz.ch/pipermail/r-help/2014-October/422455.html (has one example)


The package 'pbapply' creates a text-mode progress bar - it works on any platforms. On Windows platform, check out [http://www.theanalystatlarge.com/for-loop-tracking-windows-progress-bar/ this post]. It uses  winProgressBar() and setWinProgressBar() functions.
== 32- and 64-bit ==
See [http://cran.r-project.org/doc/manuals/R-admin.html#Choosing-between-32_002d-and-64_002dbit-builds R-admin.html].
* For speed you may want to use a 32-bit build, but to handle large datasets a 64-bit build.
* Even on 64-bit builds of R there are limits on the size of R objects, some of which stem from the use of 32-bit integers (especially in FORTRAN code). For example, the dimensionas of an array are limited to 2^31 -1.
* Since R 2.15.0, it is possible to select '64-bit Files' from the standard installer even on a 32-bit version of Windows (2012/3/30).


==== Progress bar ====
== Handling length 2^31 and more in R 3.0.0 ==
[http://peter.solymos.org/code/2016/09/11/what-is-the-cost-of-a-progress-bar-in-r.html What is the cost of a progress bar in R?]


==== lapply ====
From R News for 3.0.0 release:
Examples of using lapply + split on a data frame. See [http://rollingyours.wordpress.com/category/r-programming-apply-lapply-tapply/ rollingyours.wordpress.com].


==== sapply & vapply ====
''There is a subtle change in behaviour for numeric index values 2^31 and larger. These never used to be legitimate and so were treated as NA, sometimes with a warning. They are now legal for long vectors so there is no longer a warning, and x[2^31] <- y will now extend the vector on a 64-bit platform and give an error on a 32-bit one.
[http://stackoverflow.com/questions/12339650/why-is-vapply-safer-than-sapply This] discusses why '''vapply''' is safer and faster than sapply.
''


==== rapply - recursive version of lapply ====
In R 2.15.2, if I try to assign a vector of length 2^31, I will get an error
* http://4dpiecharts.com/tag/recursive/
<pre>
* [https://github.com/wch/r-source/search?utf8=%E2%9C%93&q=rapply Search in R source code]. Mainly [https://github.com/wch/r-source/blob/trunk/src/library/stats/R/dendrogram.R r-source/src/library/stats/R/dendrogram.R].
> x <- seq(1, 2^31)
Error in from:to : result would be too long a vector
</pre>


=== plyr and dplyr packages ===
However, for R 3.0.0 (tested on my 64-bit Ubuntu with 16GB RAM. The R was compiled by myself):
[http://www.jstatsoft.org/v40/i01/paper Paper] in J. Stat Software.
<pre>
 
> system.time(x <- seq(1,2^31))
[http://seananderson.ca/courses/12-plyr/plyr_2012.pdf A quick introduction to plyr] with a summary of apply functions in R and compare them with functions in plyr package.
  user  system elapsed
 
  8.604  11.060 120.815
# plyr has a common syntax -- easier to remember
> length(x)
# plyr requires less code since it takes care of the input and output format
[1] 2147483648
# plyr can easily be run in parallel -- faster
> length(x)/2^20
 
[1] 2048
Tutorials
> gc()
* A video of [http://cran.r-project.org/web/packages/dplyr/index.html dplyr] package can be found on [http://vimeo.com/103872918 vimeo].
            used    (Mb) gc trigger    (Mb)   max used    (Mb)
* [http://www.dataschool.io/dplyr-tutorial-for-faster-data-manipulation-in-r/ Hands-on dplyr tutorial for faster data manipulation in R] from dataschool.io.
Ncells    183823    9.9    407500    21.8    350000    18.7
 
Vcells 2147764406 16386.2 2368247221 18068.3 2148247383 16389.9
Examples of using dplyr:
>
* [http://wiekvoet.blogspot.com/2015/03/medicines-under-evaluation.html Medicines under evaluation]
* [http://rpubs.com/seandavi/GEOMetadbSurvey2014 CBI GEO Metadata Survey]
* [http://datascienceplus.com/r-for-publication-by-page-piccinini-lesson-3-logistic-regression/ Logistic Regression] by Page Piccinini. mutate(), inner_join() and %>%.
* [http://rpubs.com/turnersd/plot-deseq-results-multipage-pdf DESeq2 post analysis] select(), gather(), arrange() and %>%.  
 
==== llply() ====
llply is equivalent to lapply except that it will preserve labels and can display a progress bar. This is handy if we want to do a crazy thing.
<pre>
LLID2GOIDs <- lapply(rLLID, function(x) get("org.Hs.egGO")[[x]])
</pre>
</pre>
where rLLID is a list of entrez ID. For example,  
Note:
<pre>
# 2^31 length is about 2 Giga length. It takes about 16 GB (2^31*8/2^20 MB) memory.
get("org.Hs.egGO")[["6772"]]
# On Windows, it is almost impossible to work with 2^31 length of data if the memory is less than 16 GB because virtual disk on Windows does not work well. For example, when I tested on my 12 GB Windows 7, the whole Windows system freezes for several minutes before I force to power off the machine.
</pre>
# My slide in http://goo.gl/g7sGX shows the screenshots of running the above command on my Ubuntu and RHEL machines. As you can see the linux is pretty good at handling large (> system RAM) data. That said, as long as your linux system is 64-bit, you can possibly work on large data without too much pain.
returns a list of 49 GOs.
# For large dataset, it makes sense to use database or specially crafted packages like [http://cran.r-project.org/web/packages/bigmemory/ bigmemory] or [http://cran.r-project.org/web/packages/ff/ ff] or [https://privefl.github.io/bigstatsr/ bigstatsr].
# [https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17330 [[<- for index 2^31 fails]


==== ddply() ====
== NA in index ==
http://lamages.blogspot.com/2012/06/transforming-subsets-of-data-in-r-with.html
* Question: what is seq(1, 3)[c(1, 2, NA)]?


==== ldply() ====
Answer: It will reserve the element with NA in indexing and return the value NA for it.
[http://rpsychologist.com/an-r-script-to-automatically-look-at-pubmed-citation-counts-by-year-of-publication/ An R Script to Automatically download PubMed Citation Counts By Year of Publication]


=== mclapply() ===
* Question: What is TRUE & NA?
==== paralle package is a mult-core version of lapply() ====
Answer: NA
Note that Windows OS can not take advantage of it.


Another choice for Windows OS is to use parLapply() function in parallel package.
* Question: What is FALSE & NA?
<syntaxhighlight lang='rsplus'>
Answer: FALSE
ncores <- as.integer( Sys.getenv('NUMBER_OF_PROCESSORS') )
 
cl <- makeCluster(getOption("cl.cores", ncores))
* Question: c("A", "B", NA) != "" ?
LLID2GOIDs2 <- parLapply(cl, rLLID, function(x) {
Answer: TRUE TRUE NA
                                    library(org.Hs.eg.db); get("org.Hs.egGO")[[x]]}
 
                        )
* Question: which(c("A", "B", NA) != "") ?
stopCluster(cl)
Answer: 1 2
</syntaxhighlight>
 
It does work. Cut the computing time from 100 sec to 29 sec on 4 cores.
* Question: c(1, 2, NA) != "" & !is.na(c(1, 2, NA)) ?
Answer: TRUE TRUE FALSE
 
* Question: c("A", "B", NA) != "" & !is.na(c("A", "B", NA)) ?
Answer: TRUE TRUE FALSE
 
'''Conclusion''': In order to exclude empty or NA for numerical or character data type, we can use '''which()''' or a convenience function '''keep.complete(x) <- function(x) x != "" & !is.na(x)'''. This will guarantee return logical values and not contain NAs.


The mclapply() implementation relies on forking and Windows does not support forking. mclapply from the parallel package is implemented as a serial function on Windows systems. The ''parallelsugar'' package was created based on the above idea.
Don't just use x != "" OR !is.na(x).


==== parallelsugar package ====
=== Some functions ===
* http://edustatistics.org/nathanvan/2015/10/14/parallelsugar-an-implementation-of-mclapply-for-windows/
* X %>% [https://tidyr.tidyverse.org/reference/drop_na.html tidyr::drop_na()]
* '''stats::na.omit()''' and '''stats::complete.cases()'''. [https://statisticsglobe.com/na-omit-r-example/ NA Omit in R | 3 Example Codes for na.omit (Data Frame, Vector & by Column)]


If we load parallelsugar, the default implementation of parallel::mclapply, which used fork based clusters, will be overwritten by parallelsugar::mclapply, which is implemented with socket clusters.
== Constant and 'L' ==
Add 'L' after a constant. For example,
{{Pre}}
for(i in 1L:n) { }


<syntaxhighlight lang='rsplus'>
if (max.lines > 0L) { }
library(parallel)  


system.time( mclapply(1:4, function(xx){ Sys.sleep(10) }) )
label <- paste0(n-i+1L, ": ")
##    user  system elapsed
##    0.00    0.00  40.06


library(parallelsugar)
n <- length(x);  if(n == 0L) { }
##
</pre>
## Attaching package: ‘parallelsugar’
##
## The following object is masked from ‘package:parallel’:
##
##    mclapply


system.time( mclapply(1:4, function(xx){ Sys.sleep(10) }) )
== Vector/Arrays ==
##    user  system elapsed
R indexes arrays from 1 like Fortran, not from 0 like C or Python.
##    0.04    0.08  12.98
</syntaxhighlight>


=== Regular Expression ===
=== remove integer(0) ===
* ?grep and ?regexpr in R
[https://stackoverflow.com/a/27980810 How to remove integer(0) from a vector?]
* http://biostat.mc.vanderbilt.edu/wiki/pub/Main/SvetlanaEdenRFiles/regExprTalk.pdf
* http://www.johndcook.com/r_language_regex.html
* http://en.wikibooks.org/wiki/R_Programming/Text_Processing#Regular_Expressions
* http://rpubs.com/Lionel/19068
* http://ucfagls.wordpress.com/2012/08/15/processing-sample-labels-using-regular-expressions-in-r/
* http://www.dummies.com/how-to/content/how-to-use-regular-expressions-in-r.html
* http://www.r-bloggers.com/example-8-27-using-regular-expressions-to-read-data-with-variable-number-of-words-in-a-field/
* http://www.r-bloggers.com/using-regular-expressions-in-r-case-study-in-cleaning-a-bibtex-database/
* http://cbio.ensmp.fr/~thocking/papers/2011-08-16-directlabels-and-regular-expressions-for-useR-2011/2011-useR-named-capture-regexp.pdf
* http://stackoverflow.com/questions/5214677/r-find-the-last-dot-in-a-string
* http://stackoverflow.com/questions/10294284/remove-all-special-characters-from-a-string-in-r


Not specific to R
=== Append some elements ===
* https://en.wikipedia.org/wiki/Regular_expression
[https://www.r-bloggers.com/2023/09/3-r-functions-that-i-enjoy/ append() and its after argument]
* [https://nikic.github.io/2011/12/10/PCRE-and-newlines.html PCRE and newlines] tells the differences of \r\n (newline for Windows), \r (newline for UNIX, hex 0D) and \n (newline for old Mac, hex 0A). The tab \t has hex 09.
* http://www.autohotkey.com/docs/misc/RegEx-QuickRef.htm
* http://opencompany.org/download/regex-cheatsheet.pdf


==== Syntax ====
=== setNames() ===
The following table is from [http://www.endmemo.com/program/R/grep.php endmemo.com].
Assign names to a vector


{| class="wikitable"
<pre>
! Syntax
z <- setNames(1:3, c("a", "b", "c"))
! Description
# OR
|-
z <- 1:3; names(z) <- c("a", "b", "c")
| \\d
# OR
| Digit, 0,1,2 ... 9
z <- c("a"=1, "b"=2, "c"=3) # not work if "a", "b", "c" is like x[1], x[2], x[3].
|-
</pre>
| \\D
| Not Digit
|-
| \\s
| Space
|-
| \\S
| Not Space
|-
| \\w
| Word
|-
| \\W
| Not Word
|-
| \\t
| Tab
|-
| \\n
| New line
|-
| ^
| Beginning of the string
|-
| $
| End of the string
|-
| \
| Escape special characters, e.g. \\ is "\", \+ is "+"
|-
| |
| Alternation match. e.g. /(e|d)n/ matches "en" and "dn"
|-
| •
| Any character, except \n or line terminator
|-
| [ab]
| a or b
|-
| [^ab]
| Any character except a and b
|-
| [0-9]
| All Digit
|-
| [A-Z]
| All uppercase A to Z letters
|-
| [a-z]
| All lowercase a to z letters
|-
| [A-z]
| All Uppercase and lowercase a to z letters
|-
| i+
| i at least one time
|-
| i*
| i zero or more times
|-
| i?
| i zero or 1 time
|-
| i{n}
| i occurs n times in sequence
|-
| i{n1,n2}
| i occurs n1 - n2 times in sequence
|-
| i{n1,n2}?
| non greedy match, see above example
|-
| i{n,}
| i occures >= n times
|-
| [:alnum:]
| Alphanumeric characters: [:alpha:] and [:digit:]
|-
| [:alpha:]
| Alphabetic characters: [:lower:] and [:upper:]
|-
| [:blank:]
| Blank characters: e.g. space, tab
|-
| [:cntrl:]
| Control characters
|-
| [:digit:]
| Digits: 0 1 2 3 4 5 6 7 8 9
|-
| [:graph:]
| Graphical characters: [:alnum:] and [:punct:]
|-
| [:lower:]
| Lower-case letters in the current locale
|-
| [:print:]
| Printable characters: [:alnum:], [:punct:] and space
|-
| [:punct:]
| Punctuation character: ! " # $ % & ' ( ) * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~
|-
| [:space:]
| Space characters: tab, newline, vertical tab, form feed, carriage return, space
|-
| [:upper:]
| Upper-case letters in the current locale
|-
| [:xdigit:]
| Hexadecimal digits: 0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f
|}


==== [https://stat.ethz.ch/R-manual/R-devel/library/base/html/grep.html grep()] ====
== Factor ==
=== labels argument ===
We can specify the factor levels and new labels using the factor() function.


==== [https://stat.ethz.ch/R-manual/R-devel/library/base/html/grep.html sub() and gsub()] ====
{{Pre}}
The sub function changes only the first occurrence of the regular expression, while the gsub function performs the substitution on all occurrences within the string.
sex <- factor(sex, levels = c("0", "1"), labels = c("Male", "Female"))
drug_treatment <- factor(drug_treatment, levels = c("Placebo", "Low dose", "High dose"))
health_status <- factor(health_status, levels = c("Healthy", "Alzheimer's"))


==== [https://stat.ethz.ch/R-manual/R-devel/library/base/html/grep.html regexpr() and gregexpr()] ====
factor(rev(letters[1:3]), labels = c("A", "B", "C"))
The output from these functions is a vector of starting positions of the regular expressions which were found; if no match occurred, a value of -1 is returned.
# C B A
# Levels: A B C
</pre>


The '''regexpr''' function will only provide information about the first match in its input string(s), while the
=== Create a factor/categorical variable from a continuous variable: cut() and dplyr::case_when() ===
'''gregexpr''' function returns information about all matches found.
* [https://www.spsanderson.com/steveondata/posts/2024-03-20/index.html Mastering Data Segmentation: A Guide to Using the cut() Function in R]
:<syntaxhighlight lang='r'>
cut(
    c(0, 10, 30),
    breaks = c(0, 30, 50, Inf),
    labels = c("Young", "Middle-aged", "Elderly")
)  # Default include.lowest = FALSE
# [1] <NA>  Young Young
</syntaxhighlight>
* https://dplyr.tidyverse.org/reference/case_when.html
* [https://rpubs.com/DaveRosenman/ifelsealternative Using dplyr’s mutate and case_when functions as alternative for if else statement]
* [http://www.datasciencemadesimple.com/case-statement-r-using-case_when-dplyr/ Case when in R using case_when() Dplyr – case_when in R]
* [https://predictivehacks.com/how-to-convert-continuous-variables-into-categorical-by-creating-bins/ How To Convert Continuous Variables Into Categorical By Creating Bins]
<ul>
<li>[https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/cut ?cut]
{{Pre}}
set.seed(1)
x <- rnorm(100)
facVar <- cut(x, c(min(x), -1, 1, max(x)), labels = c("low", "medium", "high"))
table(facVar, useNA = "ifany")
facVar
#  low medium  high  <NA>
#    10    74    15      1
</pre>
Note the option '''include.lowest = TRUE''' is needed when we use cut() + quantile(); otherwise the smallest data will become NA since the intervals have the format '''(a, b]'''.
<pre>
x2 <- cut(x, quantile(x, 0:2/2), include.lowest = TRUE) # split x into 2 levels
x2 <- cut(x, quantile(x, 0:3/3), include.lowest = TRUE) # split x into 3 levels


Note that in C++, the '''std::string::find()''' and Qt's '''QRegExp::indexIn()''' can do R's '''regexpr()''' does. I am not aware of any gregexpr()-equivalent function in C++.
library(tidyverse); library(magrittr)
set.seed(1)
breaks <- quantile(runif(100), probs=seq(0, 1, len=20))
x <- runif(50)
bins <- cut(x, breaks=unique(breaks), include.lowest=T, right=T)
 
data.frame(sc=x, bins=bins) %>%
  group_by(bins) %>%
  summarise(n=n()) %>%
  ggplot(aes(x = bins, y = n)) +
    geom_col(color = "black", fill = "#90AACB") +
    theme_minimal() +
    theme(axis.text.x = element_text(angle = 90)) +  
    theme(legend.position = "none") + coord_flip()
</pre>
<li>[https://www.spsanderson.com/steveondata/posts/2024-03-20/index.html A Guide to Using the cut() Function in R]
<li>[https://youtu.be/7oyiPBjLAWY?t=2480 tibble object]
{{Pre}}
library(tidyverse)
tibble(age_yrs = c(0, 4, 10, 15, 24, 55),
      age_cat = case_when(
          age_yrs < 2 ~ "baby",
          age_yrs < 13 ~ "kid",
          age_yrs < 20 ~ "teen",
          TRUE        ~ "adult")
)
</pre>
</li>
<li>[https://youtu.be/JsNqXLl3eFc?t=96 R tip: Learn dplyr’s case_when() function]
<pre>
case_when(
  condition1 ~ value1,
  condition2 ~ value2,
  TRUE ~ ValueAnythingElse
)
# Example
case_when(
  x %%2 == 0 ~ "even",
  x %%2 == 1 ~ "odd",
  TRUE ~ "Neither even or odd"
)
</pre>
<li>
</ul>


The following example is coming from the book 'Data Manipulation with R' by [http://www.stat.berkeley.edu/~spector/ Phil Spector], Chapter 7, Character Manipulation.
=== How to change one of the level to NA ===
<syntaxhighlight lang='rsplus'>
https://stackoverflow.com/a/25354985. Note that the factor level is removed.
tst = c('one x7 two b1', 'three c5 four b9', 'five six seven', 'a8 eight nine')
<pre>
wh = regexpr('[a-z][0-9]', tst)
x <- factor(c("a", "b", "c", "NotPerformed"))
wh
levels(x)[levels(x) == 'NotPerformed'] <- NA
# [1] 5 7 -1 1
</pre>
# attr(,"match.length")
# [1] 2 2 -1 2


wh1 = gregexpr('[a-z][0-9]',tst) # return a list just like strsplit()
[https://webbedfeet.netlify.app/post/creating-missing-values-in-factors/ Creating missing values in factors]
wh1


# [[1]]
=== Concatenating two factor vectors ===
# [1] 5 12
Not trivial. [https://stackoverflow.com/a/5068939 How to concatenate factors, without them being converted to integer level?].
# attr(,"match.length")
<pre>
# [1] 2 2
unlist(list(f1, f2))
# attr(,"useBytes")
# unlist(list(factor(letters[1:5]), factor(letters[5:2])))
# [1] TRUE
</pre>
#
# [[2]]
# [1]  7 15
# attr(,"match.length")
# [1] 2 2
# attr(,"useBytes")
# [1] TRUE
#
# [[3]]
# [1] -1
# attr(,"match.length")
# [1] -1
# attr(,"useBytes")
# [1] TRUE
#
# [[4]]
# [1] 1
# attr(,"match.length")
# [1] 2
# attr(,"useBytes")
# [1] TRUE


gregexpr("'", "|3'-5'") # find the apostrophe character
=== droplevels() ===
# [[1]]
[https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/droplevels droplevels()]: drop unused levels from a factor or, more commonly, from factors in a data frame.
# [1] 3 6
# attr(,"match.length")
# [1] 1 1
# attr(,"useBytes")
# [1] TRUE
</syntaxhighlight>


==== Examples ====
=== factor(x , levels = ...) vs levels(x) <- ===
* sub("^.*boundary=", "", string) will substitute a substring which starts with 0 or more characters and then 'boundary=' with an empty. Here ^ means beginning, dot means any character and star means the preceding item 0 or more times.
<span style="color: red">Note [https://stat.ethz.ch/R-manual/R-devel/library/base/html/levels.html levels(x)] is to set/rename levels, not reorder.</span> Use <s>'''relevel()'''</s> or '''factor()''' to reorder.  
* grep("\\.zip$", pkgs) or grep("\\.tar.gz$", pkgs) will search for the string ending with .zip or .tar.gz
* grep("9.11", string) will search for the string containing '9', any character (to split 9 & 11) and '11'.
* pipe metacharacter; it is translated to 'or'. flood|fire will match strings containing floor or fire.
* [^?.]$ will match anyone ([]) not (^) ending ($) with the question mark (?) or period (.).
* ^[Gg]ood|[Bb]ad will match strings starting with Good/good and anywhere containing Bad/bad.
* ^([Gg]ood|[Bb]ad) will look for strings beginning with Good/good/Bad/bad.
* ? character; it means optional. [Gg]eorge( [Ww]\.)? [Bb]ush will match strings like 'george bush', 'George W. Bush' or 'george bushes'. Note that we escape the metacharacter dot by '\.' so it becomes a literal period.
* star and plus sign. star means any number including none and plus means at least one. For example, (.*) matches 'abc(222 )' and '()'.
* [0-9]+ (.*) [0-9]+ will match one number and following by any number of characters and a number; e.g. 'afda1080 p' and '4 by 5 size'.
* gsub("[[:space:]]+", " ", "  ab  c  ") will replace multiple spaces with 1 space.
* {} refers to as interval quantifiers; specify the minimum and maximum number of match of an expression.
* [https://github.com/wch/r-source/blob/trunk/src/library/base/R/strwrap.R#L201-L211 trimws()] function to [https://github.com/wch/r-source/blob/e36b7044ba5ca3e9caebdb0fc6302675a954ae47/doc/NEWS.Rd#L599-L600 remove trailing/leading whitespace]. The function is used in [https://github.com/wch/r-source/search?p=2&q=trimws&utf8=%E2%9C%93 several places].
<source lang="rsplus">
trimws <-
function(x, which = c("both", "left", "right"))
{
    which <- match.arg(which)
    mysub <- function(re, x) sub(re, "", x, perl = TRUE)
    if(which == "left")
        return(mysub("^[ \t\r\n]+", x))
    if(which == "right")
        return(mysub("[ \t\r\n]+$", x))
    mysub("[ \t\r\n]+$", mysub("^[ \t\r\n]+", x))
}
</source>
* [http://stackoverflow.com/questions/2261079/how-to-trim-leading-and-trailing-whitespace-in-r Another solution to trim leading/trailing space] is
<source lang="rsplus">
# returns string w/o leading whitespace
trim.leading <- function (x)  sub("^\\s+", "", x)


# returns string w/o trailing whitespace
{| class="wikitable"
trim.trailing <- function (x) sub("\\s+$", "", x)
|-
| [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/levels levels()]</br>[https://www.rdocumentation.org/packages/plyr/versions/1.8.9/topics/revalue plyr::revalue()]</br>[https://rdocumentation.org/packages/forcats/versions/1.0.0/topics/fct_recode forcats::fct_recode()]
| rename levels
|-
| [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/factor factor(, levels)]
| reorder levels
|}


# returns string w/o leading or trailing whitespace
<syntaxhighlight lang='rsplus'>
trim <- function (x) gsub("^\\s+|\\s+$", "", x)
sizes <- factor(c("small", "large", "large", "small", "medium"))
</source>
sizes
#> [1] small  large  large  small  medium
#> Levels: large medium small


=== Clipboard ===
sizes2 <- factor(sizes, levels = c("small", "medium", "large")) # reorder levels but data is not changed
<pre>
sizes2
source("clipboard")
# [1] small  large  large  small  medium
read.table("clipboard")
# Levels: small medium large
</pre>


=== read/manipulate binary data ===
sizes3 <- sizes
* x <- readBin(fn, raw(), file.info(fn)$size)
levels(sizes3) <- c("small", "medium", "large") # rename, not reorder
* rawToChar(x[1:16])
                                                # large -> small
* See Biostrings C API
                                                # medium -> medium
                                                # small -> large
sizes3
# [1] large  small  small  large  medium
# Levels: small medium large
</syntaxhighlight>
A regression example.
<syntaxhighlight lang='rsplus'>
set.seed(1)
x <- sample(1:2, 500, replace = TRUE)
y <- round(x + rnorm(500), 3)
x <- as.factor(x)
sample_data <- data.frame(x, y)
# create linear model
summary(lm( y~x, sample_data))
# Coefficients:
#            Estimate Std. Error t value Pr(>|t|)   
# (Intercept)  0.96804    0.06610  14.65  <2e-16 ***
# x2          0.99620    0.09462  10.53  <2e-16 ***


=== String Manipulation ===
# Wrong way when we want to change the baseline level to '2'
* [http://gastonsanchez.com/blog/resources/how-to/2013/09/22/Handling-and-Processing-Strings-in-R.html ebook] by Gaston Sanchez.
# No change on the model fitting except the apparent change on the variable name in the printout
* Chapter 7 of the book 'Data Manipulation with R' by Phil Spector.
levels(sample_data$x) <- c("2", "1")
* Chapter 7 of the book 'R Cookbook' by Paul Teetor.
summary(lm( y~x, sample_data))
* Chapter 2 of the book 'Using R for Data Management, Statistical Analysis and Graphics' by Horton and Kleinman.
# Coefficients:
* http://www.endmemo.com/program/R/deparse.php. '''It includes lots of examples for each R function it lists.'''
#            Estimate Std. Error t value Pr(>|t|)   
# (Intercept)  0.96804    0.06610  14.65  <2e-16 ***
# x1          0.99620    0.09462  10.53  <2e-16 ***


=== HTTPs connection ===
# Correct way if we want to change the baseline level to '2'
HTTPS connection becomes default in R 3.2.2. See
# The estimate was changed by flipping the sign from the original data
* http://blog.rstudio.org/2015/08/17/secure-https-connections-for-r/
sample_data$x <- relevel(x, ref = "2")
* http://blog.revolutionanalytics.com/2015/08/good-advice-for-security-with-r.html
summary(lm( y~x, sample_data))
# Coefficients:
#            Estimate Std. Error t value Pr(>|t|)   
# (Intercept)  1.96425    0.06770  29.01  <2e-16 ***
# x1          -0.99620    0.09462  -10.53  <2e-16 ***
</syntaxhighlight>


=== setInternet2 ===
=== stats::relevel() ===
There was a bug in ftp downloading in R 3.2.2 (r69053) Windows though it is fixed now in R 3.2 patch.
[https://www.rdocumentation.org/packages/stats/versions/3.6.2/topics/relevel relevel]. This function can only be used to change the '''reference level''' of a factor variable. '''It does not directly create an arbitrary order of levels'''. That is, it is useful in lm() or aov(), etc.


Read the [https://stat.ethz.ch/pipermail/r-devel/2015-August/071595.html discussion] reported on 8/8/2015. The error only happened on ftp not http connection. The final solution is explained in [https://stat.ethz.ch/pipermail/r-devel/2015-August/071623.html this post]. The following demonstrated the original problem.
=== reorder(), levels() and boxplot() ===
<ul>
<li>[https://www.r-bloggers.com/2023/09/how-to-reorder-boxplots-in-r-a-comprehensive-guide/ How to Reorder Boxplots in R: A Comprehensive Guide] (tapply() method, simple & effective)
<li>[https://stat.ethz.ch/R-manual/R-devel/library/stats/html/reorder.factor.html reorder()].This is useful in barplot (ggplot2::geom_col()) where we want to sort the bars by a numerical variable.
<pre>
<pre>
url <- paste0("ftp://ftp.ncbi.nlm.nih.gov/genomes/ASSEMBLY_REPORTS/All/",
# Syntax:
              "GCF_000001405.13.assembly.txt")
# newFac <- with(df, reorder(fac, vec, FUN=mean)) # newFac is like fac except it has a new order
f1 <- tempfile()
 
download.file(url, f1)
(bymedian <- with(InsectSprays, reorder(spray, count, median)) )
class(bymedian)
levels(bymedian)
boxplot(count ~ bymedian, data = InsectSprays,
        xlab = "Type of spray", ylab = "Insect count",
        main = "InsectSprays data", varwidth = TRUE,
        col = "lightgray") # boxplots are sorted according to the new levels
boxplot(count ~ spray, data = InsectSprays,
        xlab = "Type of spray", ylab = "Insect count",
        main = "InsectSprays data", varwidth = TRUE,
        col = "lightgray") # not sorted
</pre>
</pre>
It seems the bug was fixed in R 3.2-branch. See [https://github.com/wch/r-source/commit/3a02ed3a50ba17d9a093b315bf5f31ffc0e21b89 8/16/2015] patch r69089 where a new argument INTERNET_FLAG_PASSIVE was added to [https://msdn.microsoft.com/en-us/library/windows/desktop/aa385098%28v=vs.85%29.aspx InternetOpenUrl()] function of [https://msdn.microsoft.com/en-us/library/windows/desktop/aa385473%28v=vs.85%29.aspx wininet] library. [http://slacksite.com/other/ftp.html This article] and [http://stackoverflow.com/questions/1699145/what-is-the-difference-between-active-and-passive-ftp this post] explain differences of active and passive FTP.
<li>[http://www.deeplytrivial.com/2020/05/statistics-sunday-my-2019-reading.html Statistics Sunday: My 2019 Reading] (reorder function)
</ul>


The following R command will show the exact svn revision for the R you are currently using.
=== factor() vs ordered() ===
<pre>
<pre>
R.Version()$"svn rev"
factor(levels=c("a", "b", "c"), ordered=TRUE)
# ordered(0)
# Levels: a < b < c
 
factor(levels=c("a", "b", "c"))
# factor(0)
# Levels: a b c
 
ordered(levels=c("a", "b", "c"))
# Error in factor(x, ..., ordered = TRUE) :
#  argument "x" is missing, with no default
</pre>
</pre>


If setInternet2(T), then https protocol is supported in download.file().  
== Data frame ==
* http://adv-r.had.co.nz/Data-structures.html#data-frames. '''A data frame is a list of equal-length vectors'''. So a data frame is not a vector nor a matrix though it looks like a matrix.
* http://blog.datacamp.com/15-easy-solutions-data-frame-problems-r/
 
=== stringsAsFactors = FALSE ===
http://www.win-vector.com/blog/2018/03/r-tip-use-stringsasfactors-false/


When setInternet(T) is enabled by default, download.file() does not work for ftp protocol (this is used in getGEO() function of the GEOquery package). If I use setInternet(F), download.file() works again for ftp protocol.  
We can use '''options(stringsAsFactors=FALSE)''' forces R to import character data as character objects.


The setInternet2() function is defined in [https://github.com/wch/r-source/commits/trunk/src/library/utils/R/windows/sysutils.R R> src> library> utils > R > windows > sysutils.R].
In R 4.0.0, [https://developer.r-project.org/Blog/public/2020/02/16/stringsasfactors/ stringAsFactors=FALSE] will be default. This also affects read.table() function.


'''R up to 3.2.2'''
=== check.names = FALSE ===
Note this option will not affect rownames. So if the rownames contains special symbols, like dash, space, parentheses, etc, they will not be modified.
<pre>
<pre>
setInternet2 <- function(use = TRUE) .Internal(useInternet2(use))
> data.frame("1a"=1:2, "2a"=1:2, check.names = FALSE)
  1a 2a
1  1  1
2  2  2
> data.frame("1a"=1:2, "2a"=1:2) # default
  X1a X2a
1  1  1
2  2  2
</pre>
 
=== Create unique rownames: make.unique() ===
<pre>
groupCodes <- c(rep("Cont",5), rep("Tre1",5), rep("Tre2",5))
rownames(mydf) <- make.unique(groupCodes)
</pre>
</pre>
See also
* <src/include/Internal.h> (declare do_setInternet2()),
* <src/main/names.c> (show do_setInternet2() in C)
* <src/main/internet.c>  (define do_setInternet2() in C).


Note that: setInternet2(T) becomes default in R 3.2.2. To revert to the previous default use setInternet2(FALSE). See the <doc/NEWS.pdf> file.  If we use setInternet2(F), then it solves the bug of getGEO() error. But it disables the https file download using the download.file() function. In R < 3.2.2, it is also possible to download from https by setIneternet2(T).
=== data.frame() will change rownames ===
<pre>
class(df2)
# [1] "matrix" "array"
rownames(df2)[c(9109, 44999)]
# [1] "A1CF"    "A1BG-AS1"
rownames(data.frame(df2))[c(9109, 44999)]
# [1] "A1CF"    "A1BG.AS1"
</pre>


'''R 3.3.0'''
=== Print a data frame without rownames ===
<pre>
<pre>
setInternet2 <- function(use = TRUE) {
# Method 1.
    if(!is.na(use)) stop("use != NA is defunct")
rownames(df1) <- NULL
    NA
 
}
# Method 2.
print(df1, row.names = FALSE)
</pre>
</pre>


Note that setInternet2.Rd says As from \R 3.3.0 it changes nothing, and only \code{use = NA} is accepted. Also NEWS.Rd says setInternet2() has no effect and will be removed in due course.
=== Convert data frame factor columns to characters ===
[https://stackoverflow.com/questions/2851015/convert-data-frame-columns-from-factors-to-characters Convert data.frame columns from factors to characters]
{{Pre}}
# Method 1:
bob <- data.frame(lapply(bob, as.character), stringsAsFactors=FALSE)


=== read/download/source a file from internet ===
# Method 2:
==== Simple text file http ====
bob[] <- lapply(bob, as.character)
<pre>
retail <- read.csv("http://robjhyndman.com/data/ausretail.csv",header=FALSE)
</pre>
</pre>


==== Zip file and url() function ====
[https://stackoverflow.com/a/2853231 To replace only factor columns]:
<pre>
<pre>
con = gzcon(url('http://www.systematicportfolio.com/sit.gz', 'rb'))
# Method 1:
source(con)
i <- sapply(bob, is.factor)
close(con)
bob[i] <- lapply(bob[i], as.character)
 
# Method 2:
library(dplyr)
bob %>% mutate_if(is.factor, as.character) -> bob
</pre>
</pre>
Here url() function is like file(),  gzfile(), bzfile(), xzfile(), unz(), pipe(), fifo(), socketConnection(). They are used to create connections. By default, the connection is not opened (except for ‘socketConnection’), but may be opened by setting a non-empty value of argument ‘open’. See ?url.


Another example of using url() is
=== Sort Or Order A Data Frame ===
[https://howtoprogram.xyz/2018/01/07/r-how-to-order-a-data-frame/ How To Sort Or Order A Data Frame In R]
# df[order(df$x), ], df[order(df$x, decreasing = TRUE), ], df[order(df$x, df$y), ]
# library(plyr); arrange(df, x), arrange(df, desc(x)), arrange(df, x, y)
# library(dplyr); df %>% arrange(x),df %>% arrange(x, desc(x)), df %>% arrange(x, y)
# library(doBy); order(~x, df), order(~ -x, df), order(~ x+y, df)
 
=== data.frame to vector ===
<pre>
<pre>
load(url("http:/www.example.com/example.RData"))
df <- data.frame(x = c(1, 2, 3), y = c(4, 5, 6))
 
class(df)
# [1] "data.frame"
class(t(df))
# [1] "matrix" "array"
class(unlist(df))
# [1] "numeric"
 
# Method 1: Convert data frame to matrix using as.matrix()
# and then Convert matrix to vector using as.vector() or c()
mat <- as.matrix(df)
vec1 <- as.vector(mat)  # [1] 1 2 3 4 5 6
vec2 <- c(mat)
 
# Method 2: Convert data frame to matrix using t()/transpose
# and then Convert matrix to vector using as.vector() or c()
vec3 <- as.vector(t(df)) # [1] 1 4 2 5 3 6
vec4 <- c(t(df))
 
# Not working
as.vector(df)
# $x
# [1] 1 2 3
# $y
# [1] 4 5 6
 
# Method 3: unlist() - easiest solution
unlist(df)
# x1 x2 x3 y1 y2 y3
#  1  2  3  4  5  6
unlist(data.frame(df), use.names = F) # OR dplyr::pull()
# [1] 1 2 3 4 5 6
</pre>
</pre>
Q: Why as.vector(df) cannot convert a data frame into a vector?


==== [http://cran.r-project.org/web/packages/downloader/index.html downloader] package ====
A: The as.vector function cannot be used directly on a data frame to convert it into a vector because a data frame is a list of vectors (i.e., its columns) and '''as.vector only removes the attributes of an object to create a vector'''. When you apply as.vector to a data frame, R does not know how to concatenate these independent columns (which could be of different types) into a single vector. Therefore, it doesn’t perform the operation. Therefore as.vector() returns the underlying list structure of the data frame instead of converting it into a vector.
This package provides a wrapper for the download.file function, making it possible to download files over https on Windows, Mac OS X, and other Unix-like platforms. The RCurl package provides this functionality (and much more) but can be difficult to install because it must be compiled with external dependencies. This package has no external dependencies, so it is much easier to install.


==== Google drive file based on https using [http://www.omegahat.org/RCurl/FAQ.html RCurl] package ====
However, when you transpose the data frame using t(), it gets converted into a matrix. A matrix in R is a vector with dimensions. Therefore, all elements of the matrix must be of the same type. If they are not, R will coerce them to be so. Once you have a matrix, as.vector() can easily convert it into a vector because all elements are of the same type.
<pre>
require(RCurl)
myCsv <- getURL("https://docs.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0AkuuKBh0jM2TdGppUFFxcEdoUklCQlJhM2kweGpoUUE&single=true&gid=0&output=csv")
read.csv(textConnection(myCsv))
</pre>


==== Github files https using RCurl package ====
=== Using cbind() to merge vectors together? ===
* http://support.rstudio.org/help/kb/faq/configuring-r-to-use-an-http-proxy
It’s a common mistake to try and create a data frame by cbind()ing vectors together. This doesn’t work because cbind() will create a matrix unless one of the arguments is already a data frame. Instead use data.frame() directly. See [http://adv-r.had.co.nz/Data-structures.html#data-frames Advanced R -> Data structures] chapter.
* http://tonybreyal.wordpress.com/2011/11/24/source_https-sourcing-an-r-script-from-github/
 
=== cbind NULL and data.frame ===
[https://9to5tutorial.com/cbind-can-t-combine-null-with-dataframe cbind can't combine NULL with dataframe]. Add as.matrix() will fix the problem.
 
=== merge ===
* [https://thomasadventure.blog/posts/r-merging-datasets/ All You Need To Know About Merging (Joining) Datasets in R]. If we like to merge/join by the rownames, we can use '''dplyr::rownames_to_column()'''; see [https://stackoverflow.com/a/42418771 dplyr left_join() by rownames].
* [https://www.geeksforgeeks.org/merge-dataframes-by-row-names-in-r/ Merge DataFrames by Row Names in R]
* [https://jozefhajnala.gitlab.io/r/r006-merge/ How to perform merges (joins) on two or more data frames with base R, tidyverse and data.table]
* [https://www.dummies.com/programming/r/how-to-use-the-merge-function-with-data-sets-in-r/ How to understand the different types of merge]
 
Special character in the matched variable can create a trouble when we use merge() or dplyr::inner_join(). I guess R internally turns df2 (a matrix but not a data frame) to a data frame (so rownames are changed if they contain special character like "-"). This still does not explain the situation when I
<pre>
<pre>
x = getURL("https://gist.github.com/arraytools/6671098/raw/c4cb0ca6fe78054da8dbe253a05f7046270d5693/GeneIDs.txt",  
class(df1); class(df2)
            ssl.verifypeer = FALSE)
# [1] "data.frame"  # 2 x 2
read.table(text=x)
# [1] "matrix" "array" # 52439 x 2
rownames(df1)
# [1] "A1CF"    "A1BG-AS1"
merge(df1, df2[c(9109, 44999), ], by=0)
#  Row.names 786-0 A498 ACH-000001 ACH-000002
# 1  A1BG-AS1    0    0  7.321358  6.908333
# 2      A1CF    0    0  3.011470  1.189578
merge(df1, df2[c(9109, 38959:44999), ], by= 0) # still correct
merge(df1, df2[c(9109, 38958:44999), ], by= 0) # same as merge(df1, df2, by=0)
#  Row.names 786-0 A498 ACH-000001 ACH-000002
# 1      A1CF    0    0    3.01147  1.189578
rownames(df2)[38958:38959]
# [1] "ITFG2-AS1"  "ADGRD1-AS1"
 
rownames(df1)[2] <- "A1BGAS1"
rownames(df2)[44999] <- "A1BGAS1"
merge(df1, df2, by= 0)
#  Row.names 786-0 A498 ACH-000001 ACH-000002
# 1  A1BGAS1    0    0  7.321358  6.908333
# 2      A1CF    0    0  3.011470  1.189578
</pre>
</pre>
* [http://cran.r-project.org/web/packages/gistr/index.html gistr] package


=== Create publication tables using '''tables''' package ===
=== is.matrix: data.frame is not necessarily a matrix ===
See p13 for example in http://www.ianwatson.com.au/stata/tabout_tutorial.pdf
See [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/matrix ?matrix]. is.matrix returns TRUE '''if x is a vector and has a "dim" attribute of length 2''' and FALSE otherwise.  


R's [http://cran.r-project.org/web/packages/tables/index.html tables] packages is the best solution. For example,
An example that is a data frame (is.data.frame() returns TRUE) but not a matrix (is.matrix() returns FALSE) is an object returned by
<pre>
<pre>
> library(tables)
X <- data.frame(x=1:2, y=3:4)
> tabular( (Species + 1) ~ (n=1) + Format(digits=2)*
+          (Sepal.Length + Sepal.Width)*(mean + sd), data=iris )
                                                 
                Sepal.Length      Sepal.Width   
Species    n  mean        sd  mean        sd 
setosa      50 5.01        0.35 3.43        0.38
versicolor  50 5.94        0.52 2.77        0.31
virginica  50 6.59        0.64 2.97        0.32
All        150 5.84        0.83 3.06        0.44
> str(iris)
'data.frame':  150 obs. of  5 variables:
$ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
$ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
$ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
$ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
$ Species    : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...
</pre>
</pre>
and
The 'X' object is NOT a vector and it does NOT have the "dim" attribute. It has only 3 attributes: "names", "row.names" & "class". Note that dim() function works fine and returns correctly though there is not "dim" attribute.
<pre>
 
# This example shows some of the less common options       
Another example that is a data frame but not a matrix is the built-in object ''cars''; see ?matrix. It is not a vector
> Sex <- factor(sample(c("Male", "Female"), 100, rep=TRUE))
 
> Status <- factor(sample(c("low", "medium", "high"), 100, rep=TRUE))
=== Convert a data frame to a matrix: as.matrix() vs data.matrix() ===
> z <- rnorm(100)+5
If I have a data frame X which recorded the time of some files.
> fmt <- function(x) {
 
  s <- format(x, digits=2)
* is.data.frame(X) shows TRUE but is.matrix(X) show FALSE
  even <- ((1:length(s)) %% 2) == 0
* as.matrix(X) will keep the time mode. The returned object is not a data frame anymore.
  s[even] <- sprintf("(%s)", s[even])
* [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/data.matrix data.matrix(X)] will convert the time to numerical values. So use data.matrix() if the data is numeric. The returned object is not a data frame anymore.
  s
 
}
<syntaxhighlight lang='r'>
> tabular( Justify(c)*Heading()*z*Sex*Heading(Statistic)*Format(fmt())*(mean+sd) ~ Status )
# latex directory contains cache files from knitting an rmarkdown file
                  Status             
X <- list.files("latex/", full.names = T) %>%
  Sex    Statistic high   low    medium
    grep("RData", ., value=T) %>%
  Female mean      4.88   4.96   5.17
    file.info() %>% 
        sd        (1.20) (0.82) (1.35)
    `[`("mtime")
Male  mean      4.45  4.31  5.05
X %>% is.data.frame() # TRUE
        sd        (1.01) (0.93) (0.75)
X %>% is.matrix() # FALSE
X %>% as.matrix() %>% is.matrix() # TRUE
X %>% data.matrix() %>% is.matrix() # TRUE
X %>% as.matrix() %>% "["(1:2, ) # timestamps
X %>% data.matrix() %>% "["(1:2, ) # numeric
</syntaxhighlight>
 
* The '''as.matrix()''' function is used to coerce an object into a matrix. It can be used with various types of R objects, such as vectors, data frames, and arrays.
* The '''data.matrix()''' function is specifically designed for converting a data frame into a matrix by coercing all columns to numeric values. If the data frame contains non-numeric columns, such as character or factor columns, data.matrix() will convert them to numeric values if possible (e.g., by converting factors to their integer codes).
* See the following example where as.matrix() and data.matrix() return different resuls.
<syntaxhighlight lang='r'>
df <- data.frame(a = c(1, 2, 3), b = c("x", "y", "z"))
mat <- as.matrix(df)
mat
#      a  b 
# [1,] "1" "x"
# [2,] "2" "y"
# [3,] "3" "z"
class(mat)
# [1] "matrix" "array"
mat2 <- data.matrix(df)
mat2
#      a b
# [1,] 1 1
# [2,] 2 2
# [3,] 3 3
class(mat2)
# [1] "matrix" "array"
typeof(mat)
# [1] "character"
typeof(mat2)
# [1] "double"
</syntaxhighlight>
 
=== matrix vs data.frame ===
Case 1: colnames() is safer than names() if the object could be a data frame or a matrix.
<pre>
Browse[2]> names(res2$surv.data.new[[index]])
NULL
Browse[2]> colnames(res2$surv.data.new[[index]])
  [1] "time"  "status" "treat"  "AKT1"   "BRAF"  "FLOT2" "MTOR"   "PCK2"   "PIK3CA"
[10] "RAF1" 
Browse[2]> mode(res2$surv.data.new[[index]])
[1] "numeric"
Browse[2]> is.matrix(res2$surv.data.new[[index]])
[1] TRUE
Browse[2]> dim(res2$surv.data.new[[index]])
[1] 991  10
</pre>
</pre>


See also a collection of R packages related to reproducible research in http://cran.r-project.org/web/views/ReproducibleResearch.html
Case 2:
{{Pre}}
ip1 <- installed.packages()[,c(1,3:4)] # class(ip1) = 'matrix'
unique(ip1$Priority)
# Error in ip1$Priority : $ operator is invalid for atomic vectors
unique(ip1[, "Priority"])  # OK


=== Create flat tables in R console using ftable() ===
ip2 <- as.data.frame(installed.packages()[,c(1,3:4)], stringsAsFactors = FALSE) # matrix -> data.frame
<pre>
unique(ip2$Priority)     # OK
> ftable(Titanic, row.vars = 1:3)
</pre>
                  Survived  No Yes
 
Class Sex    Age                 
The length of a matrix and a data frame is different.
1st  Male  Child            0   5
{{Pre}}
            Adult          118 57
> length(matrix(1:6, 3, 2))
      Female Child            0  1
[1] 6
            Adult            4 140
> length(data.frame(matrix(1:6, 3, 2)))
2nd  Male  Child            0 11
[1] 2
            Adult          154 14
> x[1]
      Female Child            0 13
   X1
            Adult          13 80
1 1
3rd  Male  Child          35 13
2 2
            Adult          387  75
3 3
      Female Child          17  14
4 4
            Adult          89  76
5 5
Crew  Male  Child            0  0
6 6
            Adult          670 192
> x[[1]]
      Female Child            0  0
[1] 1 2 3 4 5 6
            Adult            3  20
</pre>
> ftable(Titanic, row.vars = 1:2, col.vars = "Survived")
So the length of a data frame is the number of columns. When we use sapply() function on a data frame, it will apply to each column of the data frame.
            Survived  No Yes
 
Class Sex                   
=== How to Remove Duplicates ===
1st  Male            118  62
[https://www.r-bloggers.com/2021/08/how-to-remove-duplicates-in-r-with-example/ How to Remove Duplicates in R with Example]
      Female            4 141
 
2nd  Male            154  25
=== Convert a matrix (not data frame) of characters to numeric ===
      Female          13  93
[https://stackoverflow.com/a/20791975 Just change the mode of the object]
3rd  Male            422  88
{{Pre}}
      Female          106 90
tmp <- cbind(a=c("0.12", "0.34"), b =c("0.567", "0.890")); tmp
Crew  Male            670 192
    a    b
      Female            3  20
1 0.12 0.567
> ftable(Titanic, row.vars = 2:1, col.vars = "Survived")
2 0.34 0.890
            Survived  No Yes
> is.data.frame(tmp) # FALSE
Sex    Class               
> is.matrix(tmp)    # TRUE
Male  1st            118  62
> sum(tmp)
      2nd            154  25
Error in sum(tmp) : invalid 'type' (character) of argument
      3rd            422  88
> mode(tmp) # "character"
      Crew          670 192
 
Female 1st              4 141
> mode(tmp) <- "numeric"
      2nd            13  93
> sum(tmp)
      3rd            106  90
[1] 1.917
      Crew            3  20
</pre>
> str(Titanic)
 
table [1:4, 1:2, 1:2, 1:2] 0 0 35 0 0 0 17 0 118 154 ...
=== Convert Data Frame Row to Vector ===
- attr(*, "dimnames")=List of 4
as.numeric() or '''c()'''
  ..$ Class  : chr [1:4] "1st" "2nd" "3rd" "Crew"
 
   ..$ Sex     : chr [1:2] "Male" "Female"
=== Convert characters to integers ===
  ..$ Age    : chr [1:2] "Child" "Adult"
mode(x) <- "integer"
  ..$ Survived: chr [1:2] "No" "Yes"
 
> x <- ftable(mtcars[c("cyl", "vs", "am", "gear")])
=== Non-Standard Evaluation ===
> x
[https://thomasadventure.blog/posts/understanding-nse-part1/ Understanding Non-Standard Evaluation. Part 1: The Basics]
          gear  3  4  5
 
cyl vs am             
=== Select Data Frame Columns in R ===
4  0  0        0  0  0
This is part of series of DATA MANIPULATION IN R from [https://www.datanovia.com/en/lessons/select-data-frame-columns-in-r/ datanovia.com]
      1        0  0  1
 
    1  0        1  2  0
* pull(): Extract column values as a vector. The column of interest can be specified either by name or by index.
      1        0  6  1
* select(): Extract one or multiple columns as a data table. It can be also used to remove columns from the data frame.
6  0  0        0  0  0
* select_if(): Select columns based on a particular condition. One can use this function to, for example, select columns if they are numeric.
      1       0 2 1
* Helper functions - starts_with(), ends_with(), contains(), matches(), one_of(): Select columns/variables based on their names
    1 0        2 2  0
 
      1        0  0  0
Another way is to the dollar sign '''$''' operator (?"$") to extract rows or column from a data frame.
8   0  0      12  0  0
<pre>
      1       0  0  2
class(USArrests)  # "data.frame"
     1  0        0  0  0
USArrests$"Assault"
      1        0  0  0
</pre>
> ftable(x, row.vars = c(2, 4))
Note that for both data frame and matrix objects, we need to use the '''[''' operator to extract columns and/or rows.
        cyl  4     6    8 
<pre>
        am  0  1  0  1  0  1
USArrests[c("Alabama", "Alask"), c("Murder", "Assault")]
vs gear                     
#        Murder Assault
0  3        0  0 0  0 12  0
# Alabama   13.2    236
  4         0 0  0 2 0  0
# Alaska    10.0     263
  5        0  1  0  1  0  2
USArrests[c("Murder", "Assault")] # all rows
1  3        1  0  2  0  0  0
 
  4        2  6  2  0  0  0
tmp <- data(package="datasets")
  5        0  1  0  0  0  0
class(tmp$results)  # "matrix" "array"  
>  
tmp$results[, "Item"]
> ## Start with expressions, use table()'s "dnn" to change labels
# Same method can be used if rownames are available in a matrix
> ftable(mtcars$cyl, mtcars$vs, mtcars$am, mtcars$gear, row.vars = c(2, 4),
</pre>
        dnn = c("Cylinders", "V/S", "Transmission", "Gears"))
Note for a '''data.table''' object, we can extract columns using the column names without double quotes.
<pre>
data.table(USArrests)[1:2, list(Murder, Assault)]
</pre>
 
=== Add columns to a data frame ===
[https://datasciencetut.com/how-to-add-columns-to-a-data-frame-in-r/ How to add columns to a data frame in R]
 
=== Exclude/drop/remove data frame columns ===
* [https://datasciencetut.com/remove-columns-from-a-data-frame/ How to Remove Columns from a data frame in R]
* [https://www.listendata.com/2015/06/r-keep-drop-columns-from-data-frame.html R: keep / drop columns from data frame]
<pre>
# method 1
df = subset(mydata, select = -c(x,z) )
 
# method 2
drop <- c("x","z")
df = mydata[,!(names(mydata) %in% drop)]
 
# method 3: dplyr
mydata2 = select(mydata, -a, -x, -y)
mydata2 = select(mydata, -c(a, x, y))
mydata2 = select(mydata, -a:-y)
mydata2 = mydata[,!grepl("^INC",names(mydata))]
</pre>
 
=== Remove Rows from the data frame ===
[https://datasciencetut.com/remove-rows-from-the-data-frame-in-r/ Remove Rows from the data frame in R]
 
=== Danger of selecting rows from a data frame ===
<pre>
> dim(cars)
[1] 50 2
> data.frame(a=cars[1,], b=cars[2, ])
   a.speed a.dist b.speed b.dist
1       4      2       4     10
> dim(data.frame(a=cars[1,], b=cars[2, ]))
[1] 1 4
> cars2 = as.matrix(cars)
> data.frame(a=cars2[1,], b=cars2[2, ])
      a b
speed 4
dist 2 10
</pre>
 
=== Creating data frame using structure() function ===
[https://tomaztsql.wordpress.com/2019/05/27/creating-data-frame-using-structure-function-in-r/ Creating data frame using structure() function in R]
 
=== Create an empty data.frame ===
https://stackoverflow.com/questions/10689055/create-an-empty-data-frame
<pre>
# the column types default as logical per vector(), but are then overridden
a = data.frame(matrix(vector(), 5, 3,
              dimnames=list(c(), c("Date", "File", "User"))),
              stringsAsFactors=F)
str(a) # NA but they are logical , not numeric.
a[1,1] <- rnorm(1)
str(a)
 
# similar to above
a <- data.frame(matrix(NA, nrow = 2, ncol = 3))


          Cylinders    4    6    8 
# different data type
          Transmission  0  1  0  1  0  1
a <- data.frame(x1 = character(),
V/S Gears                             
                x2 = numeric(),
0  3                  0  0  0  0 12  0
                x3 = factor(),
    4                  0  0  0  2  0  0
                stringsAsFactors = FALSE)
    5                  0  1  0  1  0  2
1  3                  1  0  2  0  0  0
    4                  2  6  2  0  0  0
    5                  0  1  0  0  0  0
</pre>
</pre>


=== tracemem, data type, copy ===
=== Objects from subsetting a row in a data frame vs matrix ===
[http://stackoverflow.com/questions/18359940/r-programming-vector-a1-2-avoid-copying-the-whole-vector/18361181#18361181 How to avoid copying a long vector]
* [https://stackoverflow.com/a/23534617 Warning: row names were found from a short variable and have been discarded]
<ul>
<li>Subsetting creates repeated rows. This will create unexpected rownames.
<pre>
R> z <- data.frame(x=1:3, y=2:4)
R> rownames(z) <- letters[1:3]
R> rownames(z)[c(1,1)]
[1] "a" "a"
R> rownames(z[c(1,1),])
[1] "a"  "a.1"
R> z[c(1,1), ]
    x y
a  1 2
a.1 1 2
</pre>
</li>
<li>[https://stackoverflow.com/a/2545548 Convert a dataframe to a vector (by rows)] The solution is as.vector(t(mydf[i, ])) or c(mydf[i, ]). My example:
{{Pre}}
str(trainData)
# 'data.frame': 503 obs. of  500 variables:
#  $ bm001: num  0.429 1 -0.5 1.415 -1.899 ...
#  $ bm002: num  0.0568 1 0.5 0.3556 -1.16 ...
# ...
trainData[1:3, 1:3]
#        bm001      bm002    bm003
# 1  0.4289449 0.05676296 1.657966
# 2 1.0000000 1.00000000 1.000000
# 3 -0.5000000 0.50000000 0.500000
o <- data.frame(time = trainData[1, ], status = trainData[2, ], treat = trainData[3, ], t(TData))
# Warning message:
# In data.frame(time = trainData[1, ], status = trainData[2, ], treat = trainData[3,  :
#   row names were found from a short variable and have been discarded
</pre>


=== Tell if the current R is running in 32-bit or 64-bit mode ===
'trees' data from the 'datasets' package
<pre>
<pre>
8 * .Machine$sizeof.pointer
trees[1:3,]
</pre>
#  Girth Height Volume
where '''sizeof.pointer''' returns the number of *bytes* in a C SEXP type and '8' means number of bits per byte.
# 1  8.3    70  10.3
# 2  8.6    65  10.3
# 3  8.8     63  10.2


=== 32- and 64-bit ===
# Wrong ways:
See [http://cran.r-project.org/doc/manuals/R-admin.html#Choosing-between-32_002d-and-64_002dbit-builds R-admin.html].
data.frame(trees[1,] , trees[2,])
* For speed you may want to use a 32-bit build, but to handle large datasets a 64-bit build.
#  Girth Height Volume Girth.1 Height.1 Volume.1
* Even on 64-bit builds of R there are limits on the size of R objects, some of which stem from the use of 32-bit integers (especially in FORTRAN code). For example, the dimensionas of an array are limited to 2^31 -1.
# 1  8.3    70  10.3    8.6      65    10.3
* Since R 2.15.0, it is possible to select '64-bit Files' from the standard installer even on a 32-bit version of Windows (2012/3/30).
data.frame(time=trees[1,] , status=trees[2,])
#  time.Girth time.Height time.Volume status.Girth status.Height status.Volume
# 1        8.3          70        10.3          8.6            65          10.3
data.frame(time=as.vector(trees[1,]) , status=as.vector(trees[2,]))
#  time.Girth time.Height time.Volume status.Girth status.Height status.Volume
# 1        8.3          70        10.3          8.6            65          10.3
data.frame(time=c(trees[1,]) , status=c(trees[2,]))
# time.Girth time.Height time.Volume status.Girth status.Height status.Volume
# 1        8.3          70        10.3         8.6            65          10.3


=== Handling length 2^31 and more in R 3.0.0 ===
# Right ways:
# method 1: dropping row names
data.frame(time=c(t(trees[1,])) , status=c(t(trees[2,])))
# OR
data.frame(time=as.numeric(trees[1,]) , status=as.numeric(trees[2,]))
#  time status
# 1  8.3   8.6
# 2 70.0   65.0
# 3 10.3  10.3
# method 2: keeping row names
data.frame(time=t(trees[1,]) , status=t(trees[2,]))
#          X1  X2
# Girth  8.3  8.6
# Height 70.0 65.0
# Volume 10.3 10.3
data.frame(time=unlist(trees[1,]) , status=unlist(trees[2,]))
#        time status
# Girth  8.3    8.6
# Height 70.0  65.0
# Volume 10.3  10.3


From R News for 3.0.0 release:
# Method 3: convert a data frame to a matrix
is.matrix(trees)
# [1] FALSE
trees2 <- as.matrix(trees)
data.frame(time=trees2[1,] , status=trees2[2,]) # row names are kept
#        time status
# Girth  8.3    8.6
# Height 70.0   65.0
# Volume 10.3  10.3


''There is a subtle change in behaviour for numeric index values 2^31 and larger. These never used to be legitimate and so were treated as NA, sometimes with a warning. They are now legal for long vectors so there is no longer a warning, and x[2^31] <- y will now extend the vector on a 64-bit platform and give an error on a 32-bit one.
dim(trees[1,])
''
# [1] 1 3
dim(trees2[1, ])
# NULL
trees[1, ]  # notice the row name '1' on the left hand side
#  Girth Height Volume
# 1  8.3    70  10.3
trees2[1, ]
#  Girth Height Volume
#    8.3  70.0  10.3
</pre>
</li>
</ul>


In R 2.15.2, if I try to assign a vector of length 2^31, I will get an error
=== Convert a list to data frame ===
[https://www.statology.org/convert-list-to-data-frame-r/ How to Convert a List to a Data Frame in R].
<pre>
<pre>
> x <- seq(1, 2^31)
# method 1
Error in from:to : result would be too long a vector
data.frame(t(sapply(my_list,c)))
 
# method 2
library(dplyr)
bind_rows(my_list) # OR bind_cols(my_list)
 
# method 3
library(data.table)
rbindlist(my_list)
</pre>
</pre>


However, for R 3.0.0 (tested on my 64-bit Ubuntu with 16GB RAM. The R was compiled by myself):
=== tibble and data.table ===
<pre>
* [[R#tibble | tibble]]
> system.time(x <- seq(1,2^31))
* [[Tidyverse#data.table|data.table]]
  user  system elapsed
 
  8.604  11.060 120.815
=== Clean  a dataset ===
> length(x)
[https://finnstats.com/index.php/2021/04/04/how-to-clean-the-datasets-in-r/ How to clean the datasets in R]
[1] 2147483648
 
> length(x)/2^20
== matrix ==
[1] 2048
> gc()
            used    (Mb) gc trigger    (Mb)  max used    (Mb)
Ncells    183823    9.9    407500    21.8    350000    18.7
Vcells 2147764406 16386.2 2368247221 18068.3 2148247383 16389.9
>
</pre>
Note:
# 2^31 length is about 2 Giga length. It takes about 16 GB (2^31*8/2^20 MB) memory.
# On Windows, it is almost impossible to work with 2^31 length of data if the memory is less than 16 GB because virtual disk on Windows does not work well. For example, when I tested on my 12 GB Windows 7, the whole Windows system freezes for several minutes before I force to power off the machine.
# My slide in http://goo.gl/g7sGX shows the screenshots of running the above command on my Ubuntu and RHEL machines. As you can see the linux is pretty good at handling large (> system RAM) data. That said, as long as your linux system is 64-bit, you can possibly work on large data without too much pain.
# For large dataset, it makes sense to use database or specially crafted packages like [http://cran.r-project.org/web/packages/bigmemory/ bigmemory] or [http://cran.r-project.org/web/packages/ff/ ff].


=== NA in index ===
=== Define and subset a matrix ===
* Question: what is seq(1, 3)[c(1, 2, NA)]?
* [https://www.tutorialkart.com/r-tutorial/r-matrix/ Matrix in R]
** It is clear when a vector becomes a matrix the data is transformed column-wisely ('''byrow''' = FALSE, by default).
** When subsetting a matrix, it follows the format: '''X[rows, colums]''' or '''X[y-axis, x-axis]'''.


Answer: It will reserve the element with NA in indexing and return the value NA for it.
<pre>
data <- c(2, 4, 7, 5, 10, 1)
A <- matrix(data, ncol = 3)
print(A)
#      [,1] [,2] [,3]
# [1,]    2    7  10
# [2,]    4    5    1


* Question: What is TRUE & NA?
A[1:1, 2:3, drop=F]
Answer: NA
#      [,1] [,2]
# [1,]    7  10
</pre>


* Question: What is FALSE & NA?
=== Prevent automatic conversion of single column to vector ===
Answer: FALSE
use '''drop = FALSE''' such as mat[, 1, drop = FALSE].


* Question: c("A", "B", NA) != "" ?
=== complete.cases(): remove rows with missing in any column ===
Answer: TRUE TRUE NA
It works on a sequence of vectors, matrices and data frames.


* Question: which(c("A", "B", NA) != "") ?
=== NROW vs nrow ===
Answer: 1 2
[https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/nrow ?nrow]. Use NROW/NCOL instead of nrow/ncol to treat vectors as 1-column matrices.


* Question: c(1, 2, NA) != "" & !is.na(c(1, 2, NA)) ?
=== matrix (column-major order) multiply a vector ===
Answer: TRUE TRUE FALSE
* Matrices in R [https://en.wikipedia.org/wiki/Row-_and_column-major_order#Programming_languages_and_libraries R (like Fortran) are stored in a column-major order]. It means array slice A[,1] are contiguous.


* Question: c("A", "B", NA) != "" & !is.na(c("A", "B", NA)) ?
{{Pre}}
Answer: TRUE TRUE FALSE
> matrix(1:6, 3,2)
    [,1] [,2]
[1,]    1    4
[2,]    2    5
[3,]    3    6
> matrix(1:6, 3,2) * c(1,2,3) # c(1,2,3) will be recycled to form a matrix. Good quiz.
    [,1] [,2]
[1,]    1    4
[2,]    4  10
[3,]    9  18
> matrix(1:6, 3,2) * c(1,2,3,4) # c(1,2,3,4) will be recycled
    [,1] [,2]
[1,]    1  16
[2,]    4    5
[3,]    9  12
</pre>


'''Conclusion''': In order to exclude empty or NA for numerical or character data type, we can use '''which()''' or a convenience function '''keep.complete(x) <- function(x) x != "" & !is.na(x)'''. This will guarantee return logical values and not contain NAs.
* [https://stackoverflow.com/a/20596490 How to divide each row of a matrix by elements of a vector in R]


Don't just use x != "" OR !is.na(x).
=== add a vector to all rows of a matrix ===
[https://stackoverflow.com/a/39443126 add a vector to all rows of a matrix]. sweep() or rep() is the best.


=== Constant ===
=== sparse matrix ===
Add 'L' after a constant. For example,
[https://stackoverflow.com/a/10555270 R convert matrix or data frame to sparseMatrix]
<syntaxhighlight lang='rsplus'>
 
for(i in 1L:n) { }
To subset a vector from some column of a sparseMatrix, we need to convert it to a regular vector, '''as.vector()'''.
 
== Attributes ==
* [https://statisticaloddsandends.wordpress.com/2020/10/19/attributes-in-r/ Attributes in R]
* [http://adv-r.had.co.nz/Data-structures.html#attributes Data structures] in "Advanced R"
 
== Names ==
[https://masalmon.eu/2023/11/06/functions-dealing-with-names/ Useful functions for dealing with object names]. (Un)Setting object names: stats::setNames(), unname() and rlang::set_names()


if (max.lines > 0L) { }
=== Print a vector by suppressing names ===
Use '''unname'''. sapply(, , USE.NAMES = FALSE).


label <- paste0(n-i+1L, ": ")
== format.pval/print p-values/format p values ==
[https://rdrr.io/r/base/format.pval.html format.pval()]. By default it will show 5 significant digits (getOption("digits")-2).
{{Pre}}
> set.seed(1); format.pval(c(stats::runif(5), pi^-100, NA))
[1] "0.26551" "0.37212" "0.57285" "0.90821" "0.20168" "< 2e-16" "NA"
> format.pval(c(0.1, 0.0001, 1e-27))
[1] "1e-01"  "1e-04"  "<2e-16"


n <- length(x);  if(n == 0L) { }
R> pvalue
</syntaxhighlight>
[1] 0.0004632104
R> print(pvalue, digits =20)
[1] 0.00046321036188223807528
R> format.pval(pvalue)
[1] "0.00046321"
R> format.pval(pvalue * 1e-1)
[1] "4.6321e-05"
R> format.pval(0.00004632)
[1] "4.632e-05"
R> getOption("digits")
[1] 7
</pre>


=== Data frame ===
=== Return type ===
* http://blog.datacamp.com/15-easy-solutions-data-frame-problems-r/
The format.pval() function returns a string, so it’s not appropriate to use the returned object for operations like sorting.


=== data.frame to vector ===
=== Wrong number of digits in format.pval() ===
See [https://stackoverflow.com/questions/59779131/wrong-number-of-digits-in-format-pval here]. The solution is to apply round() and then format.pval().
<pre>
<pre>
> a= matrix(1:6, 2,3)
x <- c(6.25433625041843e-05, NA, 0.220313341361346, NA, 0.154029880744594,
> rownames(a) <- c("a", "b")
  0.0378437685448703, 0.023358329881356, NA, 0.0262561986351483,  
> colnames(a) <- c("x", "y", "z")
  0.000251274794673796)  
> a
format.pval(x, digits=3)
  x y z
# [1] "6.25e-05" "NA"      "0.220313" "NA"      "0.154030" "0.037844" "0.023358"
a 1 3 5
# [8] "NA"       "0.026256" "0.000251"
b 2 4 6
 
> unlist(data.frame(a))
round(x, 3) |> format.pval(digits=3, eps=.001)
x1 x2 y1 y2 z1 z2
# [1] "<0.001" "NA"    "0.220" "NA"    "0.154" "0.038" "0.023" "NA"
2 3 4 5 6
# [9] "0.026" "<0.001"
</pre>
</pre>


=== matrix vs data.frame ===
=== dplr::mutate_if() ===
<pre>
<pre>
ip1 <- installed.packages()[,c(1,3:4)] # class(ip1) = 'matrix'
library(dplyr)
unique(ip1$Priority)
df <- data.frame(
# Error in ip1$Priority : $ operator is invalid for atomic vectors
  char_var = c("A", "B", "C"),
unique(ip1[, "Priority"])   # OK
  num_var1 = c(1.123456, 2.123456, 3.123456),
  num_var2 = c(4.654321, 5.654321, 6.654321),
  stringsAsFactors = FALSE
)


ip2 <- as.data.frame(installed.packages()[,c(1,3:4)], stringsAsFactors = FALSE) # matrix -> data.frame
# Round numerical variables to 4 digits after the decimal point
unique(ip2$Priority)    # OK
df_rounded <- df %>%
  mutate_if(is.numeric, round, digits = 4)
</pre>
</pre>


=== Print a vector by suppressing names ===
== Customize R: options() ==
Use '''unname'''.
 
=== Change the default R repository, my .Rprofile ===
[[Rstudio#Change_repository|Change R repository]]


=== sprintf does not print ===
Edit global Rprofile file. On *NIX platforms, it's located in /usr/lib/R/library/base/R/Rprofile although local '''.Rprofile''' settings take precedence.
Use cat() or print() outside sprintf(). sprintf() do not print in a non interactive mode.
<syntaxhighlight lang='rsplus'>
cat(sprintf('%5.2f\t%i\n',1.234, l234))
</syntaxhighlight>


=== Creating publication quality graphs in R ===
For example, I can specify the R mirror I like by creating a single line '''.Rprofile''' file under my home directory. Another good choice of repository is '''cloud.r-project.org'''.
* http://teachpress.environmentalinformatics-marburg.de/2013/07/creating-publication-quality-graphs-in-r-7/


=== Write unix format files on Windows and vice versa ===
Type '''file.edit("~/.Rprofile")'''
https://stat.ethz.ch/pipermail/r-devel/2012-April/063931.html
{{Pre}}
local({
  r = getOption("repos")
  r["CRAN"] = "https://cran.rstudio.com/"
  options(repos = r)
})
options(continue = "  ", editor = "nano")
message("Hi MC, loading ~/.Rprofile")
if (interactive()) {
  .Last <- function() try(savehistory("~/.Rhistory"))
}
</pre>


=== with() and within() functions ===
=== Change the default web browser for utils::browseURL() ===
within() is similar to with() except it is used to create new columns and merge them with the original data sets. See [http://www.youtube.com/watch?v=pZ6Bnxg9E8w&list=PLOU2XLYxmsIK9qQfztXeybpHvru-TrqAP youtube video].
When I run help.start() function in LXLE, it cannot find its default web browser (seamonkey). The solution is to put
<pre>
<pre>
closePr <- with(mariokart, totalPr - shipPr)
options(browser='seamonkey')
head(closePr, 20)
</pre>
 
in the '''.Rprofile''' of your home directory. If the browser is not in the global PATH, we need to put the full path above.
mk <- within(mariokart, {
            closePr <- totalPr - shipPr
    })
head(mk) # new column closePr


mk <- mariokart
For one-time only purpose, we can use the ''browser'' option in help.start() function:
aggregate(. ~ wheels + cond, mk, mean)
{{Pre}}
# create mean according to each level of (wheels, cond)
> help.start(browser="seamonkey")
If the browser launched by 'seamonkey' is already running, it is *not*
    restarted, and you must switch to its window.
Otherwise, be patient ...
</pre>


aggregate(totalPr ~ wheels + cond, mk, mean)
We can work made a change (or create the file) ~/.Renviron or etc/Renviron. See
* [https://stat.ethz.ch/pipermail/r-help/2003-August/037484.html Changing default browser in options()].
* https://stat.ethz.ch/R-manual/R-devel/library/utils/html/browseURL.html


tapply(mk$totalPr, mk[, c("wheels", "cond")], mean)
=== Change the default editor ===
On my Linux and mac, the default editor is "vi". To change it to "nano",
{{Pre}}
options(editor = "nano")
</pre>
</pre>


=== 15 Questions All R Users Have About Plots ===
=== Change prompt and remove '+' sign ===
See http://blog.datacamp.com/15-questions-about-r-plots/. This is a tremendous post. It covers
See https://stackoverflow.com/a/1448823.
{{Pre}}
options(prompt="R> ", continue=" ")
</pre>


# How To Draw An Empty R Plot?
=== digits ===
# How To Set The Axis Labels And Title Of The R Plots?
* [https://gist.github.com/arraytools/26a0b359541f4fc9fddc8f0a0c94489e Read and compute the sum of a numeric matrix file] using R vs Python vs C++. Note by default R does not show digits after the decimal point because the number is large.
# How To Add And Change The Spacing Of The Tick Marks Of Your R Plot
* [https://stackoverflow.com/a/2288013 Controlling number of decimal digits in print output in R]
# How To Create Two Different X- or Y-axes
* [https://stackoverflow.com/a/10712012 ?print.default]
# How To Add Or Change The R Plot’s Legend?
* [https://stackoverflow.com/a/12135122 Formatting Decimal places in R, round()]. [https://www.rdocumentation.org/packages/base/versions/3.5.3/topics/format format()] where '''nsmall''' controls the minimum number of digits to the right of the decimal point
# How To Draw A Grid In Your R Plot?
* [https://bugs.r-project.org/bugzilla/show_bug.cgi?id=17668 numerical error in round() causing round to even to fail] 2019-12-05
# How To Draw A Plot With A PNG As Background?
<ul>
# How To Adjust The Size Of Points In An R Plot?
<li>[https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/Round signif()] rounds x to n significant digits.
# How To Fit A Smooth Curve To Your R Data
# How To Add Error Bars In An R Plot
# How To Save A Plot As An Image On Disc
# How To Plot Two R Plots Next To Each Other?
# How To Plot Multiple Lines Or Points?
# How To Fix The Aspect Ratio For Your R Plots
# What Is The Function Of hjust And vjust In ggplot2?
 
=== Scatterplot with rugs ===
<pre>
<pre>
require(stats) # both 'density' and its default method
R> signif(pi, 3)
with(faithful, {
[1] 3.14
    plot(density(eruptions, bw = 0.15))
R> signif(pi, 5)
    rug(eruptions)
[1] 3.1416
    rug(jitter(eruptions, amount = 0.01), side = 3, col = "light blue")
})
</pre>
</pre>
[[File:RugFunction.png|200px]]
</li>
</ul>
* The default digits 7 may be too small. For example, '''if a number is very large, then we may not be able to see (enough) value after the decimal point'''. The acceptable range is 1-22. See the following examples


=== Draw a single plot with two different y-axes ===
In R,
* http://www.gettinggeneticsdone.com/2015/04/r-single-plot-with-two-different-y-axes.html
{{Pre}}
> options()$digits # Default
[1] 7
> print(.1+.2, digits=18)
[1] 0.300000000000000044
> 100000.07 + .04
[1] 100000.1
> options(digits = 16)
> 100000.07 + .04
[1] 100000.11
</pre>


=== Barplot with values ===
In Python,
* [http://stackoverflow.com/questions/12481430/how-to-display-the-frequency-at-the-top-of-each-factor-in-a-barplot-in-r barplot(), text() and axis()] functions. The data can be from a table() object.
{{Pre}}
* [http://stackoverflow.com/questions/27466035/adding-values-to-barplot-of-table-in-r two bars in one factor] (stack). The data can be a 2-dim matrix with numerical values.
>>> 100000.07 + .04
* [http://stats.stackexchange.com/questions/3879/how-to-put-values-over-bars-in-barplot-in-r two bars in one factor] (next to each other)
100000.11
</pre>


=== Draw Color Palette ===
=== [https://stackoverflow.com/questions/5352099/how-to-disable-scientific-notation Disable scientific notation in printing]: options(scipen) ===
* http://teachpress.environmentalinformatics-marburg.de/2013/07/creating-publication-quality-graphs-in-r-7/
[https://datasciencetut.com/how-to-turn-off-scientific-notation-in-r/ How to Turn Off Scientific Notation in R?]


=== svg and html ===
This also helps with write.table() results. For example, 0.0003 won't become 3e-4 in the output file.
* http://www.magesblog.com/2016/02/using-svg-graphics-in-blog-posts.html
{{Pre}}
> numer = 29707; denom = 93874
> c(numer/denom, numer, denom)
[1] 3.164561e-01 2.970700e+04 9.387400e+04
 
# Method 1. Without changing the global option
> format(c(numer/denom, numer, denom), scientific=FALSE)
[1] "    0.3164561" "29707.0000000" "93874.0000000"


=== read.table - read only specific columns ===
# Method 2. Change the global option
Use 'colClasses' option in read.table, read.delim, .... For example, the following example reads only the 3rd column of the text file and also changes its data type from a data frame to a vector. Note that we have include double quotes around NULL.
> options(scipen=999)
<syntaxhighlight lang="rsplus">
> numer/denom
x <- read.table("var_annot.vcf", colClasses = c(rep("NULL", 2), "character", rep("NULL", 7)),
[1] 0.3164561
                skip=62, header=T, stringsAsFactors = FALSE)[, 1]
> c(numer/denom, numer, denom)
#
[1]     0.3164561 29707.0000000 93874.0000000
system.time(x <- read.delim("Methylation450k.txt",
> c(4/5, numer, denom)
                colClasses = c("character", "numeric", rep("NULL", 188)), stringsAsFactors = FALSE))
[1]    0.8 29707.0 93874.0
</syntaxhighlight>
</pre>


To know the number of columns, we might want to read the first row first.
=== Suppress warnings: options() and capture.output() ===
<syntaxhighlight lang="rsplus">
Use [https://www.rdocumentation.org/packages/base/versions/3.4.1/topics/options options()]. If ''warn'' is negative all warnings are ignored. If ''warn'' is zero (the default) warnings are stored until the top--level function returns.  
library(magrittr)
{{Pre}}
scan("var_annot.vcf", sep="\t", what="character", skip=62, nlines=1, quiet=TRUE) %>% length()
op <- options("warn")
</syntaxhighlight>
options(warn = -1)
....
options(op)


=== Read excel files ===
# OR
* http://www.milanor.net/blog/?p=779
warnLevel <- options()$warn
My experience is to save the Excel file as csv file (before it can be read into R) if it is possible.
options(warn = -1)
...
options(warn = warnLevel)
</pre>


=== Serialization ===
[https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/warning suppressWarnings()]
If we want to pass an R object to C (use recv() function), we can use writeBin() to output the stream size and then use serialize() function to output the stream to a file. See the
[https://stat.ethz.ch/pipermail/r-devel/attachments/20130628/56473803/attachment.pl post] on R mailing list.
<pre>
<pre>
> a <- list(1,2,3)
suppressWarnings( foo() )
> a_serial <- serialize(a, NULL)
 
> a_length <- length(a_serial)
foo <- capture.output(  
> a_length
bar <- suppressWarnings(  
[1] 70
{print( "hello, world" );
> writeBin(as.integer(a_length), connection, endian="big")
  warning("unwanted" )} ) )  
> serialize(a, connection)
</pre>
</pre>
In C++ process, I receive one int variable first to get the length, and
then read <length> bytes from the connection.


=== socketConnection ===
[https://www.rdocumentation.org/packages/utils/versions/3.6.2/topics/capture.output capture.output()]
See ?socketconnection.
<pre>
str(iris, max.level=1) %>% capture.output(file = "/tmp/iris.txt")
</pre>


==== Simple example ====
=== Converts warnings into errors ===
from the socketConnection's manual.
options(warn=2)


Open one R session
=== demo() function ===
<ul>
<li>[https://stackoverflow.com/a/18746519 How to wait for a keypress in R?] PS [https://stat.ethz.ch/R-manual/R-devel/library/base/html/readline.html readline()] is different from readLines().
<pre>
<pre>
con1 <- socketConnection(port = 22131, server = TRUE) # wait until a connection from some client
for(i in 1:2) { print(i); readline("Press [enter] to continue")}
writeLines(LETTERS, con1)
close(con1)
</pre>
</pre>
 
<li>Hit 'ESC' or Ctrl+c to skip the prompt "Hit <Return> to see next plot:" </li>
Open another R session (client)
<li>demo() uses [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/options options()] to ask users to hit Enter on each plot
<pre>
<pre>
con2 <- socketConnection(Sys.info()["nodename"], port = 22131)
op <- options(device.ask.default = ask) # ask = TRUE
# as non-blocking, may need to loop for input
on.exit(options(op), add = TRUE)
readLines(con2)
while(isIncomplete(con2)) {
  Sys.sleep(1)
  z <- readLines(con2)
  if(length(z)) print(z)
}
close(con2)
</pre>
</pre>
</li>
</ul>


==== Use nc in client ====
== sprintf ==
=== paste, paste0, sprintf ===
[https://www.r-bloggers.com/paste-paste0-and-sprintf/ this post], [https://www.r-bloggers.com/2023/09/3-r-functions-that-i-enjoy/ 3 R functions that I enjoy]


The client does not have to be the R. We can use telnet, nc, etc. See the post [https://stat.ethz.ch/pipermail/r-sig-hpc/2009-April/000144.html here]. For example, on the client machine, we can issue
=== sep vs collapse in paste() ===
* sep is used if we supply '''multiple separate objects''' to paste(). A more powerful function is [https://tidyr.tidyverse.org/reference/unite.html tidyr::unite()] function.
* collapse is used to make the output of length 1. It is commonly used if we have only 1 input object
<pre>
<pre>
nc localhost 22131  [ENTER]
R> paste("a", "A", sep=",") # multi-vec -> multi-vec
[1] "a,A"
R> paste(c("Elon", "Taylor"), c("Mask", "Swift"))
[1] "Elon Mask"    "Taylor Swift"
# OR
R> sprintf("%s, %s", c("Elon", "Taylor"), c("Mask", "Swift"))
 
R> paste(c("a", "A"), collapse="-") # one-vec/multi-vec  -> one-scale
[1] "a-A"
 
# When use together, sep first and collapse second
R> paste(letters[1:3], LETTERS[1:3], sep=",", collapse=" - ")
[1] "a,A - b,B - c,C"
R> paste(letters[1:3], LETTERS[1:3], sep=",")
[1] "a,A" "b,B" "c,C"
R> paste(letters[1:3], LETTERS[1:3], sep=",") |> paste(collapse=" - ")
[1] "a,A - b,B - c,C"
</pre>
</pre>
Then the client will wait and show anything written from the server machine. The connection from nc will be terminated once close(con1) is given.


If I use the command
=== Format number as fixed width, with leading zeros ===
<pre>
* https://stackoverflow.com/questions/8266915/format-number-as-fixed-width-with-leading-zeros
nc -v -w 2 localhost -z 22130-22135
* https://stackoverflow.com/questions/14409084/pad-with-leading-zeros-to-common-width?rq=1
</pre>
 
then the connection will be established for a short time which means the cursor on the server machine will be returned. If we issue the above nc command again on the client machine it will show the connection to the port 22131 is refused. PS. "-w" switch denotes the number of seconds of the timeout for connects and final net reads.
{{Pre}}
# sprintf()
a <- seq(1,101,25)
sprintf("name_%03d", a)
[1] "name_001" "name_026" "name_051" "name_076" "name_101"


Some post I don't have a chance to read. http://digitheadslabnotebook.blogspot.com/2010/09/how-to-send-http-put-request-from-r.html
# formatC()
paste("name", formatC(a, width=3, flag="0"), sep="_")
[1] "name_001" "name_026" "name_051" "name_076" "name_101"


==== Use curl command in client ====
# gsub()
On the server,
paste0("bm", gsub(" ", "0", format(5:15)))
<pre>
# [1] "bm05" "bm06" "bm07" "bm08" "bm09" "bm10" "bm11" "bm12" "bm13" "bm14" "bm15"
con1 <- socketConnection(port = 8080, server = TRUE)
</pre>
</pre>


On the client,
=== formatC and prettyNum (prettifying numbers) ===
* [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/formatC formatC() & prettyNum()]
* [[R#format.pval|format.pval()]]
<pre>
<pre>
curl --trace-ascii debugdump.txt http://localhost:8080/
R> (x <- 1.2345 * 10 ^ (-8:4))
[1] 1.2345e-08 1.2345e-07 1.2345e-06 1.2345e-05 1.2345e-04 1.2345e-03
[7] 1.2345e-02 1.2345e-01 1.2345e+00 1.2345e+01 1.2345e+02 1.2345e+03
[13] 1.2345e+04
R> formatC(x)
[1] "1.234e-08" "1.234e-07" "1.234e-06" "1.234e-05" "0.0001234" "0.001234"
[7] "0.01235"  "0.1235"    "1.234"    "12.34"    "123.4"    "1234"
[13] "1.234e+04"
R> formatC(x, digits=3)
[1] "1.23e-08" "1.23e-07" "1.23e-06" "1.23e-05" "0.000123" "0.00123"
[7] "0.0123"  "0.123"    "1.23"    "12.3"    " 123"    "1.23e+03"
[13] "1.23e+04"
R> formatC(x, digits=3, format="e")
[1] "1.234e-08" "1.234e-07" "1.234e-06" "1.234e-05" "1.234e-04" "1.234e-03"
[7] "1.235e-02" "1.235e-01" "1.234e+00" "1.234e+01" "1.234e+02" "1.234e+03"
[13] "1.234e+04"
 
R> x <- .000012345
R> prettyNum(x)
[1] "1.2345e-05"
R> x <- .00012345
R> prettyNum(x)
[1] "0.00012345"
</pre>
</pre>


Then go to the server,
=== format(x, scientific = TRUE) vs round() vs format.pval() ===
<pre>
Print numeric data in exponential format, so .0001 prints as 1e-4
while(nchar(x <- readLines(con1, 1)) > 0) cat(x, "\n")
<syntaxhighlight lang='r'>
format(c(0.00001156, 0.84134, 2.1669), scientific = T, digits=4)
# [1] "1.156e-05" "8.413e-01" "2.167e+00"
round(c(0.00001156, 0.84134, 2.1669), digits=4)
# [1] 0.0000 0.8413 2.1669


close(con1) # return cursor in the client machine
format.pval(c(0.00001156, 0.84134, 2.1669)) # output is char vector
</pre>
# [1] "1.156e-05" "0.84134"  "2.16690"
format.pval(c(0.00001156, 0.84134, 2.1669), digits=4)
# [1] "1.156e-05" "0.8413"    "2.1669"
</syntaxhighlight>


==== Use telnet command in client ====
== Creating publication quality graphs in R ==
On the server,
* http://teachpress.environmentalinformatics-marburg.de/2013/07/creating-publication-quality-graphs-in-r-7/
<pre>
con1 <- socketConnection(port = 8080, server = TRUE)
</pre>


On the client,
== HDF5 : Hierarchical Data Format==
<pre>
HDF5 is an open binary file format for storing and managing large, complex datasets. The file format was developed by the HDF Group, and is widely used in scientific computing.
sudo apt-get install telnet
telnet localhost 8080
abcdefg
hijklmn
qestst
</pre>


Go to the server,
* https://en.wikipedia.org/wiki/Hierarchical_Data_Format
<pre>
* [https://support.hdfgroup.org/HDF5/ HDF5 tutorial] and others
readLines(con1, 1)
* [http://www.bioconductor.org/packages/release/bioc/html/rhdf5.html rhdf5] package
readLines(con1, 1)
* rhdf5 is used by [http://amp.pharm.mssm.edu/archs4/data.html ARCHS4] where you can download R program that will download hdf5 file storing expression and metadata such as gene ID, sample/GSM ID, tissues, et al.
readLines(con1, 1)
close(con1) # return cursor in the client machine
</pre>


Some [http://blog.gahooa.com/2009/01/23/basics-of-telnet-and-http/ tutorial] about using telnet on http request. And [http://unixhelp.ed.ac.uk/tables/telnet_commands.html this] is a summary of using telnet.
== Formats for writing/saving and sharing data ==
[http://www.econometricsbysimulation.com/2016/12/efficiently-saving-and-sharing-data-in-r_46.html Efficiently Saving and Sharing Data in R]


=== Subsetting ===
== Write unix format files on Windows and vice versa ==
[http://lib.stat.cmu.edu/R/CRAN/doc/manuals/R-lang.html#Subset-assignment Subset assignment of R Language Definition] and [http://lib.stat.cmu.edu/R/CRAN/doc/manuals/R-lang.html#Manipulation-of-functions Manipulation of functions].
https://stat.ethz.ch/pipermail/r-devel/2012-April/063931.html


The result of the command '''x[3:5] <- 13:15''' is as if the following had been executed
== with() and within() functions ==
* [https://www.r-bloggers.com/2023/07/simplify-your-code-with-rs-powerful-functions-with-and-within/ Simplify Your Code with R’s Powerful Functions: with() and within()]
* within() is similar to with() except it is used to create new columns and merge them with the original data sets. But if we just want to create a new column, we can just use df$newVar = . The following example is from [http://www.youtube.com/watch?v=pZ6Bnxg9E8w&list=PLOU2XLYxmsIK9qQfztXeybpHvru-TrqAP youtube video].
<pre>
<pre>
`*tmp*` <- x
closePr <- with(mariokart, totalPr - shipPr)
x <- "[<-"(`*tmp*`, 3:5, value=13:15)
head(closePr, 20)
rm(`*tmp*`)
 
mk <- within(mariokart, {
            closePr <- totalPr - shipPr
    })
head(mk) # new column closePr
 
mk <- mariokart
aggregate(. ~ wheels + cond, mk, mean)
# create mean according to each level of (wheels, cond)
 
aggregate(totalPr ~ wheels + cond, mk, mean)
 
tapply(mk$totalPr, mk[, c("wheels", "cond")], mean)
</pre>
</pre>


=== S3 and S4 ===
== stem(): stem-and-leaf plot (alternative to histogram), bar chart on terminals ==
* Software for Data Analysis: Programming with R by John Chambers
* https://en.wikipedia.org/wiki/Stem-and-leaf_display
* Programming with Data: A Guide to the S Language  by John Chambers
* [https://www.dataanalytics.org.uk/tally-plots-in-r/ Tally plots in R]
* https://www.rmetrics.org/files/Meielisalp2009/Presentations/Chalabi1.pdf
* https://stackoverflow.com/questions/14736556/ascii-plotting-functions-for-r
* https://www.stat.auckland.ac.nz/S-Workshop/Gentleman/S4Objects.pdf
* [https://cran.r-project.org/web/packages/txtplot/index.html txtplot] package
* [http://cran.r-project.org/web/packages/packS4/index.html packS4: Toy Example of S4 Package]
 
* http://www.cyclismo.org/tutorial/R/s4Classes.html
== Plot histograms as lines ==
* http://adv-r.had.co.nz/S4.html
https://stackoverflow.com/a/16681279. This is useful when we want to compare the distribution from different statistics.  
<pre>
x2=invisible(hist(out2$EB))
y2=invisible(hist(out2$Bench))
z2=invisible(hist(out2$EB0.001))


To get the source code of S4 methods, we can use showMethod(), getMethod() and showMethod(). For example
plot(x=x2$mids, y=x2$density, type="l")
<syntaxhighlight lang='rsplus'>
lines(y2$mids, y2$density, lty=2, pwd=2)
library(qrqc)
lines(z2$mids, z2$density, lty=3, pwd=2)
showMethods("gcPlot")
</pre>
getMethod("gcPlot", "FASTQSummary") # get an error
showMethods("gcPlot", "FASTQSummary") # good.
</syntaxhighlight>


* '''getClassDef()''' in S4 ([http://www.bioconductor.org/help/course-materials/2014/Epigenomics/BiocForSequenceAnalysis.html Bioconductor course]).
== Histogram with density line ==
<syntaxhighlight lang='rsplus'>
<pre>
library(IRanges)
hist(x, prob = TRUE)
ir <- IRanges(start=c(10, 20, 30), width=5)
lines(density(x), col = 4, lwd = 2)
ir
</pre>
The overlayed density may looks strange in cases for example counts from single-cell RNASeq or p-values from RNASeq (there is a peak around x=0).


class(ir)
== Graphical Parameters, Axes and Text, Combining Plots ==
## [1] "IRanges"
[http://www.statmethods.net/advgraphs/axes.html statmethods.net]
## attr(,"package")
## [1] "IRanges"


getClassDef(class(ir))
== 15 Questions All R Users Have About Plots ==
## Class "IRanges" [package "IRanges"]
See [https://www.datacamp.com/tutorial/15-questions-about-r-plots 15 Questions All R Users Have About Plots]. This is a tremendous post. It covers the built-in plot() function and ggplot() from ggplot2 package.
##
 
## Slots:
# How To Draw An Empty R Plot? plot.new()
##                                                                     
# How To Set The Axis Labels And Title Of The R Plots?
## Name:            start          width          NAMES    elementType
# How To Add And Change The Spacing Of The Tick Marks Of Your R Plot? axis()
## Class:         integer        integer characterORNULL      character
# How To Create Two Different X- or Y-axes? par(new=TRUE), axis(), mtext(). [https://www.rdocumentation.org/packages/graphics/versions/3.6.2/topics/par ?par].
##                                     
# How To Add Or Change The R Plot’s Legend? legend()
## Name: elementMetadata        metadata
# How To Draw A Grid In Your R Plot? [https://r-charts.com/base-r/grid/ grid()]
## Class: DataTableORNULL            list
# How To Draw A Plot With A PNG As Background? rasterImage() from the '''png''' package
##
# How To Adjust The Size Of Points In An R Plot? cex argument
## Extends:
# How To Fit A Smooth Curve To Your R Data? loess() and lines()
## Class "Ranges", directly
# How To Add Error Bars In An R Plot? arrows()
## Class "IntegerList", by class "Ranges", distance 2
# How To Save A Plot As An Image On Disc
## Class "RangesORmissing", by class "Ranges", distance 2
# How To Plot Two R Plots Next To Each Other? '''par(mfrow)'''[which means Multiple Figures (use ROW-wise)], '''gridBase''' package, '''lattice''' package
## Class "AtomicList", by class "Ranges", distance 3
# How To Plot Multiple Lines Or Points? plot(), lines()
## Class "List", by class "Ranges", distance 4
# How To Fix The Aspect Ratio For Your R Plots? asp parameter
## Class "Vector", by class "Ranges", distance 5
# What Is The Function Of hjust And vjust In ggplot2?
## Class "Annotated", by class "Ranges", distance 6
 
##
== jitter function ==
## Known Subclasses: "NormalIRanges"
* https://www.rdocumentation.org/packages/base/versions/3.5.2/topics/jitter
</syntaxhighlight>
** jitter(, amount) function adds a random variation between -amount/2 and amount/2 to each element in x
==== mcols() and DataFrame() from Bioc [http://bioconductor.org/packages/release/bioc/html/S4Vectors.html S4Vectors] package ====
* [https://stackoverflow.com/a/17552046 What does the “jitter” function do in R?]
* mcols: Get or set the metadata columns.
* [https://www.r-bloggers.com/2023/09/when-to-use-jitter/ When to use Jitter]
* colData: SummarizedExperiment instances from GenomicRanges
* [https://stats.stackexchange.com/a/146174 How to calculate Area Under the Curve (AUC), or the c-statistic, by hand]
* DataFrame: The DataFrame class extends the DataTable virtual class and supports the storage of any type of object (with length and [ methods) as columns.  
 
:[[File:Jitterbox.png|200px]]


For example, in [http://www-huber.embl.de/DESeq2paper/vignettes/posterior.pdf Shrinkage of logarithmic fold changes] vignette of the DESeq2paper package
== Scatterplot with the "rug" function ==
<syntaxhighlight lang='rsplus'>
<pre>
> mcols(ddsNoPrior[genes, ])
require(stats) # both 'density' and its default method
DataFrame with 2 rows and 21 columns
with(faithful, {
  baseMean  baseVar  allZero dispGeneEst    dispFit dispersion  dispIter dispOutlier  dispMAP
     plot(density(eruptions, bw = 0.15))
  <numeric> <numeric> <logical>  <numeric>  <numeric>  <numeric> <numeric>  <logical> <numeric>
    rug(eruptions)
1  163.5750  8904.607     FALSE  0.06263141 0.03862798  0.0577712        7      FALSE 0.0577712
     rug(jitter(eruptions, amount = 0.01), side = 3, col = "light blue")
2  175.3883 59643.515     FALSE  2.25306109 0.03807917  2.2530611        12        TRUE 1.6011440
})
  Intercept strain_DBA.2J_vs_C57BL.6J SE_Intercept SE_strain_DBA.2J_vs_C57BL.6J WaldStatistic_Intercept
</pre>
  <numeric>                <numeric>    <numeric>                    <numeric>              <numeric>
[[:File:RugFunction.png]]
1  6.210188                  1.735829    0.1229354                    0.1636645              50.515872
 
2  6.234880                  1.823173    0.6870629                    0.9481865                9.074686
See also the [https://stat.ethz.ch/R-manual/R-devel/library/graphics/html/stripchart.html stripchart()] function which produces one dimensional scatter plots (or dot plots) of the given data.
  WaldStatistic_strain_DBA.2J_vs_C57BL.6J WaldPvalue_Intercept WaldPvalue_strain_DBA.2J_vs_C57BL.6J
 
                                <numeric>           <numeric>                           <numeric>
== Identify/Locate Points in a Scatter Plot ==
1                                10.60602        0.000000e+00                        2.793908e-26
<ul>
2                                1.92280        1.140054e-19                        5.450522e-02
<li>[https://www.rdocumentation.org/packages/graphics/versions/3.5.1/topics/identify ?identify]
  betaConv  betaIter  deviance  maxCooks
<li>[https://stackoverflow.com/a/23234142 Using the identify function in R]
  <logical> <numeric> <numeric> <numeric>
<pre>
1     TRUE        3  210.4045 0.2648753
plot(x, y)
2      TRUE        9  243.7455 0.3248949
identify(x, y, labels = names, plot = TRUE)
</syntaxhighlight>
# Use left clicks to select points we want to identify and "esc" to stop the process
# This will put the labels on the plot and also return the indices of points
# [1] 143
names[143]
</pre>
</ul>


=== findInterval() ===
== Draw a single plot with two different y-axes ==
Related functions are cuts() and split(). See also
* http://www.gettinggeneticsdone.com/2015/04/r-single-plot-with-two-different-y-axes.html
* [http://books.google.com/books?id=oKY5QeSWb4cC&pg=PT310&lpg=PT310&dq=r+findinterval3&source=bl&ots=YjNMkHrTMw&sig=y_wIA1um420xVCI5IoGivABge-s&hl=en&sa=X&ei=gm_yUrSqLKXesAS2_IGoBQ&ved=0CFIQ6AEwBTgo#v=onepage&q=r%20findinterval3&f=false R Graphs Cookbook]
* [http://adv-r.had.co.nz/Rcpp.html Hadley Wickham]


=== do.call, rbind, lapply ===
== Draw Color Palette ==
Lots of examples. See for example [https://stat.ethz.ch/pipermail/r-help/attachments/20140423/62d8d103/attachment.pl this one] for creating a data frame from a vector.
* http://teachpress.environmentalinformatics-marburg.de/2013/07/creating-publication-quality-graphs-in-r-7/
<syntaxhighlight lang='rsplus'>
 
x <- readLines(textConnection("---CLUSTER 1 ---
=== Default palette before R 4.0 ===
3
palette() # black, red, green3, blue, cyan, magenta, yellow, gray
  4
 
  5
<pre>
  6
# Example from Coursera "Statistics for Genomic Data Science" by Jeff Leek
  ---CLUSTER 2 ---
tropical = c('darkorange', 'dodgerblue', 'hotpink', 'limegreen', 'yellow')
9
palette(tropical)
10
plot(1:5, 1:5, col=1:5, pch=16, cex=5)
8
</pre>
11"))
 
=== New palette in R 4.0.0 ===
[https://youtu.be/I4k0LkTOKvU?t=464 R 4.0: 3 new features], [https://blog.revolutionanalytics.com/2020/04/r-400-is-released.html R 4.0.0 now available, and a look back at R's history]. For example, we can select "ggplot2" palette to make the base graphics charts that match the color scheme of ggplot2.
<pre>
R> palette()
[1] "black"  "#DF536B" "#61D04F" "#2297E6" "#28E2E5" "#CD0BBC" "#F5C710"
[8] "gray62"
R> palette.pals()
[1] "R3"              "R4"              "ggplot2"      
[4] "Okabe-Ito"      "Accent"          "Dark 2"       
[7] "Paired"          "Pastel 1"        "Pastel 2"     
[10] "Set 1"          "Set 2"          "Set 3"         
[13] "Tableau 10"      "Classic Tableau" "Polychrome 36"  
[16] "Alphabet"
R> palette.colors(palette='R4') # same as palette()
[1] "#000000" "#DF536B" "#61D04F" "#2297E6" "#28E2E5" "#CD0BBC" "#F5C710"
[8] "#9E9E9E"
R> palette("R3") # nothing return on screen but palette has changed
R> palette()
[1] "black"  "red"    "green3" "blue"    "cyan"    "magenta" "yellow"
[8] "gray"  
R> palette("R4") # reset to the default color palette; OR palette("default")
 
R> scales::show_col(palette.colors(palette = "Okabe-Ito"))
R> for(id in palette.pals()) {
    scales::show_col(palette.colors(palette = id))
    title(id)
    readline("Press [enter] to continue")
  }
</pre>
The '''palette''' function can also be used to change the color palette. See [https://data.library.virginia.edu/setting-up-color-palettes-in-r/ Setting up Color Palettes in R]
<pre>
palette("ggplot2")
palette(palette()[-1]) # Remove 'black'
  # OR palette(palette.colors(palette = "ggplot2")[-1] )
with(iris, plot(Sepal.Length, Petal.Length, col = Species, pch=16))


# create a list of where the 'clusters' are
cc <- palette()
clust <- c(grep("CLUSTER", x), length(x) + 1L)
palette(c(cc,"purple","brown")) # Add two colors
</pre>
<pre>
R> colors() |> length() # [1] 657
R> colors(distinct = T) |> length() # [1] 502
</pre>


# get size of each cluster
=== evoPalette ===
clustSize <- diff(clust) - 1L
[http://gradientdescending.com/evolve-new-colour-palettes-in-r-with-evopalette/ Evolve new colour palettes in R with evoPalette]


# get cluster number
=== rtist ===
clustNum <- gsub("[^0-9]+", "", x[grep("CLUSTER", x)])
[https://github.com/tomasokal/rtist?s=09 rtist]: Use the palettes of famous artists in your own visualizations.


result <- do.call(rbind, lapply(seq(length(clustNum)), function(.cl){
== SVG ==
    cbind(Object = x[seq(clust[.cl] + 1L, length = clustSize[.cl])]
=== Embed svg in html ===
        , Cluster = .cl
* http://www.magesblog.com/2016/02/using-svg-graphics-in-blog-posts.html
        )
    }))


result
=== svglite ===
svglite is better R's svg(). It was used by ggsave().
[https://www.rstudio.com/blog/svglite-1-2-0/ svglite 1.2.0], [https://r-graphics.org/recipe-output-vector-svg R Graphics Cookbook].


    Object Cluster
=== pdf -> svg ===
[1,] "3"    "1"
Using Inkscape. See [https://robertgrantstats.wordpress.com/2017/09/07/svg-from-stats-software-the-good-the-bad-and-the-ugly/ this post].
[2,] "4"    "1"
[3,] "5"    "1"
[4,] "6"    "1"
[5,] "9"    "2"
[6,] "10"  "2"
[7,] "8"    "2"
[8,] "11"  "2"
</syntaxhighlight>


A 2nd example is to [http://datascienceplus.com/working-with-data-frame-in-r/ sort a data frame] by using do.call(order, list()).
=== svg -> png ===
[https://laustep.github.io/stlahblog/posts/SVG2PNG.html SVG to PNG] using the [https://cran.rstudio.com/web/packages/gyro/index.html gyro] package


=== How to get examples from help file ===
== read.table ==
See [https://stat.ethz.ch/pipermail/r-help/2014-April/369342.html this post].
=== clipboard ===
Method 1:
{{Pre}}
<pre>
source("clipboard")
example(acf, give.lines=TRUE)
read.table("clipboard")
</pre>
</pre>
Method 2:
 
<pre>
=== inline text ===
Rd <- utils:::.getHelpFile(?acf)
{{Pre}}
tools::Rd2ex(Rd)
mydf <- read.table(header=T, text='
cond yval
    A 2
    B 2.5
    C 1.6
')
</pre>
</pre>


=== "[" and "[[" with the sapply() function ===
=== http(s) connection ===
Suppose we want to extract string from the id like "ABC-123-XYZ" before the first hyphen.
{{Pre}}
<pre>
temp = getURL("https://gist.github.com/arraytools/6743826/raw/23c8b0bc4b8f0d1bfe1c2fad985ca2e091aeb916/ip.txt",
sapply(strsplit("ABC-123-XYZ", "-"), "[", 1)
                          ssl.verifypeer = FALSE)
ip <- read.table(textConnection(temp), as.is=TRUE)
</pre>
</pre>
is the same as
 
<pre>
=== read only specific columns ===
sapply(strsplit("ABC-123-XYZ", "-"), function(x) x[1])
Use 'colClasses' option in read.table, read.delim, .... For example, the following example reads only the 3rd column of the text file and also changes its data type from a data frame to a vector. Note that we have include double quotes around NULL.
{{Pre}}
x <- read.table("var_annot.vcf", colClasses = c(rep("NULL", 2), "character", rep("NULL", 7)),  
                skip=62, header=T, stringsAsFactors = FALSE)[, 1]
#
system.time(x <- read.delim("Methylation450k.txt",
                colClasses = c("character", "numeric", rep("NULL", 188)), stringsAsFactors = FALSE))
</pre>
</pre>


=== Dealing with date ===
To know the number of columns, we might want to read the first row first.
<pre>
{{Pre}}
d1 = date()
library(magrittr)
class(d1) # "character"
scan("var_annot.vcf", sep="\t", what="character", skip=62, nlines=1, quiet=TRUE) %>% length()
d2 = Sys.Date()
</pre>
class(d2) # "Date"
 
format(d2, "%a %b %d")


library(lubridate); ymd("20140108") # "2014-01-08 UTC"
Another method is to use '''pipe()''', '''cut''' or '''awk'''. See [https://stackoverflow.com/questions/2193742/ways-to-read-only-select-columns-from-a-file-into-r-a-happy-medium-between-re ways to read only selected columns from a file into R]
mdy("08/04/2013") # "2013-08-04 UTC"
dmy("03-04-2013") # "2013-04-03 UTC"
ymd_hms("2011-08-03 10:15:03") # "2011-08-03 10:15:03 UTC"
ymd_hms("2011-08-03 10:15:03", tz="Pacific/Auckland")
# "2011-08-03 10:15:03 NZST"
?Sys.timezone
x = dmy(c("1jan2013", "2jan2013", "31mar2013", "30jul2013"))
wday(x[1]) # 3
wday(x[1], label=TRUE) # Tues
</pre>
* http://www.r-statistics.com/2012/03/do-more-with-dates-and-times-in-r-with-lubridate-1-1-0/
* http://cran.r-project.org/web/packages/lubridate/vignettes/lubridate.html
* http://rpubs.com/seandavi/GEOMetadbSurvey2014
* We want our dates and times as class "Date" or the class "POSIXct", "POSIXlt". For more information type ?POSIXlt.


=== [http://adv-r.had.co.nz/Computing-on-the-language.html Nonstandard evaluation] ===
=== check.names = FALSE in read.table() ===
* substitute(expr, env) - capture expression. substitute() is often paired with deparse() to create informative labels for data sets and plots.
* quote(expr) - similar to substitute() but do nothing??
* eval(expr, envir), evalq(expr, envir) - eval evaluates its first argument in the current scope before passing it to the evaluator: evalq avoids this.
* deparse(expr) - turns unevaluated expressions into character strings. For example,
<pre>
<pre>
> deparse(args(lm))
gx <- read.table(file, header = T, row.names =1)
[1] "function (formula, data, subset, weights, na.action, method = \"qr\", "  
colnames(gx) %>% grep("[^[:alnum:] ]", ., value = TRUE)
[2] "    model = TRUE, x = FALSE, y = FALSE, qr = TRUE, singular.ok = TRUE, "
# [1] "hCG_1642354" "IGH."        "IGHV1.69"    "IGKV1.5"     "IGKV2.24"    "KRTAP13.2"
[3] "    contrasts = NULL, offset, ...) "                                  
# [7] "KRTAP19.1"  "KRTAP2.4"    "KRTAP5.9"    "KRTAP6.3"   "Kua.UEV"
[4] "NULL"    


> deparse(args(lm), width=20)
gx <- read.table(file, header = T, row.names =1, check.names = FALSE)
[1] "function (formula, data, "        "    subset, weights, "         
colnames(gx) %>% grep("[^[:alnum:] ]", ., value = TRUE)
[3] "   na.action, method = \"qr\", " "    model = TRUE, x = FALSE, "  
# [1] "hCG_1642354" "IGH@"       "IGHV1-69"    "IGKV1-5"     "IGKV2-24"    "KRTAP13-2" 
[5] "   y = FALSE, qr = TRUE, "       "    singular.ok = TRUE, "      
# [7] "KRTAP19-1"  "KRTAP2-4"    "KRTAP5-9"    "KRTAP6-3"    "Kua-UEV"
[7] "    contrasts = NULL, "           "    offset, ...) "              
[9] "NULL"
</pre>
</pre>
* parse(text) - returns the parsed but unevaluated expressions in a list. See [[R#Create_a_Simple_Socket_Server_in_R|Create a Simple Socket Server in R]] for the application of ''eval(parse(text))''.


=== The ‘…’ argument ===
=== setNames() ===
See [http://cran.r-project.org/doc/manuals/R-intro.html#The-three-dots-argument Section 10.4 of An Introduction to R]. Especially, the expression '''list(...)''' evaluates all such arguments and returns them in a named list
Change the colnames. See an example from [https://www.tidymodels.org/start/models/ tidymodels]


=== Lazy evaluation in R functions arguments ===
=== Testing for valid variable names ===
* http://adv-r.had.co.nz/Functions.html
[https://www.r-bloggers.com/testing-for-valid-variable-names/ Testing for valid variable names]
* https://stat.ethz.ch/pipermail/r-devel/2015-February/070688.html


'''R function arguments are lazy — they’re only evaluated if they’re actually used'''.  
=== make.names(): Make syntactically valid names out of character vectors ===
 
* [https://stat.ethz.ch/R-manual/R-devel/library/base/html/make.names.html make.names()]
* Example 1. By default, R function arguments are lazy.
* A valid variable name consists of letters, numbers and the '''dot''' or '''underline''' characters. The variable name starts with a letter or the dot not followed by a number. See [https://www.tutorialspoint.com/r/r_variables.htm R variables].
<pre>
<pre>
f <- function(x) {
make.names("abc-d") # [1] "abc.d"
  999
}
f(stop("This is an error!"))
#> [1] 999
</pre>
</pre>


* Example 2. If you want to ensure that an argument is evaluated you can use '''force()'''.
== Serialization ==
If we want to pass an R object to C (use recv() function), we can use writeBin() to output the stream size and then use serialize() function to output the stream to a file. See the
[https://stat.ethz.ch/pipermail/r-devel/attachments/20130628/56473803/attachment.pl post] on R mailing list.
<pre>
<pre>
add <- function(x) {
> a <- list(1,2,3)
  force(x)
> a_serial <- serialize(a, NULL)
  function(y) x + y
> a_length <- length(a_serial)
}
> a_length
adders2 <- lapply(1:10, add)
[1] 70
adders2[[1]](10)
> writeBin(as.integer(a_length), connection, endian="big")
#> [1] 11
> serialize(a, connection)
adders2[[10]](10)
#> [1] 20
</pre>
</pre>
In C++ process, I receive one int variable first to get the length, and
then read <length> bytes from the connection.


* Example 3. Default arguments are evaluated inside the function.
== socketConnection ==
See ?socketconnection.  
 
=== Simple example ===
from the socketConnection's manual.
 
Open one R session
<pre>
<pre>
f <- function(x = ls()) {
con1 <- socketConnection(port = 22131, server = TRUE) # wait until a connection from some client
  a <- 1
writeLines(LETTERS, con1)
  x
close(con1)
}
 
# ls() evaluated inside f:
f()
# [1] "a" "x"
 
# ls() evaluated in global environment:
f(ls())
# [1] "add"    "adders" "f"
</pre>
</pre>


* Example 4. Laziness is useful in if statements — the second statement below will be evaluated only if the first is true.
Open another R session (client)
<pre>
<pre>
x <- NULL
con2 <- socketConnection(Sys.info()["nodename"], port = 22131)
if (!is.null(x) && x > 0) {
# as non-blocking, may need to loop for input
 
readLines(con2)
while(isIncomplete(con2)) {
  Sys.sleep(1)
  z <- readLines(con2)
  if(length(z)) print(z)
}
}
close(con2)
</pre>
</pre>


=== Backtick sign, infix/prefix/postfix operators ===  
=== Use nc in client ===
The backtick sign ` (not the single quote) refers to functions or variables that have otherwise reserved or illegal names; e.g. '&&', '+', '(', 'for', 'if', etc. See some examples in [http://adv-r.had.co.nz/Functions.html this note].


'''[http://en.wikipedia.org/wiki/Infix_notation infix]''' operator.
The client does not have to be the R. We can use telnet, nc, etc. See the post [https://stat.ethz.ch/pipermail/r-sig-hpc/2009-April/000144.html here]. For example, on the client machine, we can issue
<pre>
<pre>
1 + 2    # infix
nc localhost 22131  [ENTER]
+ 1 2    # prefix
1 2 +    # postfix
</pre>
</pre>
Then the client will wait and show anything written from the server machine. The connection from nc will be terminated once close(con1) is given.


=== List data type ===
If I use the command
==== [http://adv-r.had.co.nz/Functions.html Calling a function given a list of arguments] ====
<pre>
<pre>
> args <- list(c(1:10, NA, NA), na.rm = TRUE)
nc -v -w 2 localhost -z 22130-22135
> do.call(mean, args)
[1] 5.5
> mean(c(1:10, NA, NA), na.rm = TRUE)
[1] 5.5
</pre>
</pre>
then the connection will be established for a short time which means the cursor on the server machine will be returned. If we issue the above nc command again on the client machine it will show the connection to the port 22131 is refused. PS. "-w" switch denotes the number of seconds of the timeout for connects and final net reads.
Some post I don't have a chance to read. http://digitheadslabnotebook.blogspot.com/2010/09/how-to-send-http-put-request-from-r.html


=== Error handling and exceptions ===
=== Use curl command in client ===
* http://adv-r.had.co.nz/Exceptions-Debugging.html
On the server,
* try() allows execution to continue even after an error has occurred. You can suppress the message with try(..., silent = TRUE).
<pre>
<pre>
out <- try({
con1 <- socketConnection(port = 8080, server = TRUE)
  a <- 1
</pre>
  b <- "x"
  a + b
})


elements <- list(1:10, c(-1, 10), c(T, F), letters)
On the client,
results <- lapply(elements, log)
<pre>
is.error <- function(x) inherits(x, "try-error")
curl --trace-ascii debugdump.txt http://localhost:8080/
succeeded <- !sapply(results, is.error)
</pre>
</pre>
* tryCatch(): With tryCatch() you map conditions to handlers (like switch()), named functions that are called with the condition as an input. Note that try() is a simplified version of tryCatch().
 
Then go to the server,
<pre>
<pre>
tryCatch(expr, ..., finally)
while(nchar(x <- readLines(con1, 1)) > 0) cat(x, "\n")
 
close(con1) # return cursor in the client machine
</pre>


show_condition <- function(code) {
=== Use telnet command in client ===
  tryCatch(code,
On the server,
    error = function(c) "error",
<pre>
    warning = function(c) "warning",
con1 <- socketConnection(port = 8080, server = TRUE)
    message = function(c) "message"
  )
}
show_condition(stop("!"))
#> [1] "error"
show_condition(warning("?!"))
#> [1] "warning"
show_condition(message("?"))
#> [1] "message"
show_condition(10)
#> [1] 10
</pre>
</pre>
Below is another snippet from available.packages() function,
 
On the client,
<pre>
<pre>
z <- tryCatch(download.file(....), error = identity)
sudo apt-get install telnet
if (!inherits(z, "error")) STATEMENTS
telnet localhost 8080
abcdefg
hijklmn
qestst
</pre>
</pre>


=== Using list type ===
Go to the server,
==== Avoid if-else or switch ====
?plot.stepfun.
<pre>
<pre>
y0 <- c(1,2,4,3)
readLines(con1, 1)
sfun0  <- stepfun(1:3, y0, f = 0)
readLines(con1, 1)
sfun.2 <- stepfun(1:3, y0, f = .2)
readLines(con1, 1)
sfun1  <- stepfun(1:3, y0, right = TRUE)
close(con1) # return cursor in the client machine
 
for(i in 1:3)
  lines(list(sfun0, sfun.2, stepfun(1:3, y0, f = 1))[[i]], col = i)
legend(2.5, 1.9, paste("f =", c(0, 0.2, 1)), col = 1:3, lty = 1, y.intersp = 1)
</pre>
</pre>


=== Open a new Window device ===
Some [http://blog.gahooa.com/2009/01/23/basics-of-telnet-and-http/ tutorial] about using telnet on http request. And [http://unixhelp.ed.ac.uk/tables/telnet_commands.html this] is a summary of using telnet.
X11() or dev.new()


=== par() ===
== Subsetting ==
?par
[http://lib.stat.cmu.edu/R/CRAN/doc/manuals/R-lang.html#Subset-assignment Subset assignment of R Language Definition] and [http://lib.stat.cmu.edu/R/CRAN/doc/manuals/R-lang.html#Manipulation-of-functions Manipulation of functions].


==== layout ====
The result of the command '''x[3:5] <- 13:15''' is as if the following had been executed
http://datascienceplus.com/adding-text-to-r-plot/
<pre>
`*tmp*` <- x
x <- "[<-"(`*tmp*`, 3:5, value=13:15)
rm(`*tmp*`)
</pre>


==== mtext vs title ====
=== Avoid Coercing Indices To Doubles ===
http://datascienceplus.com/adding-text-to-r-plot/
[https://www.jottr.org/2018/04/02/coercion-of-indices/ 1 or 1L]


==== mgp ====
=== Careful on NA value ===
The margin line (in ‘mex’ units) for the axis title, axis labels and axis line. Note that ‘mgp[1]’ affects ‘title’ whereas ‘mgp[2:3]’ affect ‘axis’. The default is ‘c(3, 1, 0)’.
See the example below. base::subset() or dplyr::filter() can remove NA subsets.
<pre>
R> mydf = data.frame(a=1:3, b=c(NA,5,6))
R> mydf[mydf$b >5, ]
    a  b
NA NA NA
3  3 6
R> mydf[which(mydf$b >5), ]
  a b
3 3 6
R> mydf %>% dplyr::filter(b > 5)
  a b
1 3 6
R> subset(mydf, b>5)
  a b
3 3 6
</pre>


If we like to make the axis labels closer to an axis, we can use mgp=c(2.3, 1, 0) for example.
=== Implicit looping ===
<pre>
set.seed(1)
i <- sample(c(TRUE, FALSE), size=10, replace = TRUE)
# [1]  TRUE FALSE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE FALSE FALSE
sum(i)        # [1] 6
x <- 1:10
length(x[i])  # [1] 6
x[i[1:3]]    # [1]  1  3 4  6  7  9 10
length(x[i[1:3]]) # [1] 7
</pre>


==== lty ====
== modelling ==
1=solid (default), 2=dashed, 3=dotted, 4=dotdash, 5=longdash, 6=twodash
=== update() ===
* [https://www.rdocumentation.org/packages/stats/versions/3.6.1/topics/update ?update]
* [https://stackoverflow.com/a/5118337 Reusing a Model Built in R]


==== oma  ====
=== Extract all variable names in lm(), glm(), ... ===
The following trick is useful when we want to draw multiple plots with a common title.
all.vars(formula(Model)[-2])


<pre>
=== as.formula(): use a string in formula in lm(), glm(), ... ===
par(mfrow=c(1,2),oma = c(0, 0, 2, 0))  # oma=c(0, 0, 0, 0) by default
* [https://www.r-bloggers.com/2019/08/changing-the-variable-inside-an-r-formula/ Changing the variable inside an R formula]
plot(1:10,  main="Plot 1")
* [https://stackoverflow.com/questions/5251507/how-to-succinctly-write-a-formula-with-many-variables-from-a-data-frame How to succinctly write a formula with many variables from a data frame?]
plot(1:100, main="Plot 2")
{{Pre}}
mtext("Title for Two Plots", outer = TRUE, cex = 1.5) # outer=FALSE by default
? as.formula
xnam <- paste("x", 1:25, sep="")
fmla <- as.formula(paste("y ~ ", paste(xnam, collapse= "+")))
</pre>
</pre>
* [http://www.win-vector.com/blog/2018/09/r-tip-how-to-pass-a-formula-to-lm/ How to Pass A formula to lm], [https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/bquote ?bquote], [https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/eval ?eval]
{{Pre}}
outcome <- "mpg"
variables <- c("cyl", "disp", "hp", "carb")


=== Suppress warnings ===
# Method 1. The 'Call' portion of the model is reported as “formula = f”
<pre>
# our modeling effort,
op <- options("warn")
# fully parameterized!
options(warn = -1)
f <- as.formula(
....
  paste(outcome,
options(op)
        paste(variables, collapse = " + "),
</pre>
        sep = " ~ "))
print(f)
# mpg ~ cyl + disp + hp + carb
 
model <- lm(f, data = mtcars)
print(model)
 
# Call:
#  lm(formula = f, data = mtcars)
#
# Coefficients:
#  (Intercept)         cyl        disp          hp        carb 
#    34.021595    -1.048523    -0.026906    0.009349    -0.926863 


=== save() vs saveRDS() ===
# Method 2. eval() + bquote() + ".()"
# saveRDS() can only save one R object while save() does not have this constraint.
format(terms(model)) #  or model$terms
# saveRDS() doesn’t save the both the object and its name it just saves a representation of the object. As a result, the saved object can be loaded into a named object within R that is different from the name it had when originally serialized. See [http://www.fromthebottomoftheheap.net/2012/04/01/saving-and-loading-r-objects/ this post].
# [1] "mpg ~ cyl + disp + hp + carb"
<pre>
x <- 5
saveRDS(x, "myfile.rds")
x2 <- readRDS("myfile.rds")
identical(mod, mod2, ignore.environment = TRUE)
</pre>


=== all.equal(), identical() ===
# The new line of code
* all.equal: compare R objects x and y testing ‘near equality’
model <- eval(bquote(  lm(.(f), data = mtcars)  ))
* identical: The safe and reliable way to test two objects for being exactly equal.
 
print(model)
# Call:
#  lm(formula = mpg ~ cyl + disp + hp + carb, data = mtcars)
#
# Coefficients:
#  (Intercept)          cyl        disp          hp        carb 
#    34.021595    -1.048523    -0.026906    0.009349    -0.926863 
 
# Note if we skip ".()" operator
> eval(bquote(  lm(f, data = mtcars)  ))
 
Call:
lm(formula = f, data = mtcars)
 
Coefficients:
(Intercept)          cyl        disp          hp        carb 
  34.021595    -1.048523    -0.026906    0.009349    -0.926863
</pre>
* [https://statisticaloddsandends.wordpress.com/2019/08/24/changing-the-variable-inside-an-r-formula/ Changing the variable inside an R formula] 1. as.formula() 2. subset by [[i]] 3. get() 4. eval(parse()).
 
=== reformulate ===
[https://www.r-bloggers.com/2023/06/simplifying-model-formulas-with-the-r-function-reformulate/ Simplifying Model Formulas with the R Function ‘reformulate()’]
 
=== I() function ===
I() means isolates. See [https://stackoverflow.com/a/24192745 What does the capital letter "I" in R linear regression formula mean?],  [https://stackoverflow.com/a/8055683 In R formulas, why do I have to use the I() function on power terms, like y ~ I(x^3)]
 
=== Aggregating results from linear model ===
https://stats.stackexchange.com/a/6862
 
== Replacement function "fun(x) <- a" ==
[https://stackoverflow.com/questions/11563154/what-are-replacement-functions-in-r What are Replacement Functions in R?]
<pre>
R> xx <- c(1,3,66, 99)
R> "cutoff<-" <- function(x, value){
    x[x > value] <- Inf
    x
}
R> cutoff(xx) <- 65 # xx & 65 are both input
R> xx
[1]  1  3 Inf Inf
 
R> "cutoff<-"(x = xx, value = 65)
[1]  1  3 Inf Inf
</pre>
The statement '''fun(x) <- a''' and R will read '''x <- "fun<-"(x,a) '''
 
== S3 and S4 methods and signature ==
* How S4 works in R https://www.rdocumentation.org/packages/methods/versions/3.5.1/topics/Methods_Details
* Software for Data Analysis: Programming with R by John Chambers
* Programming with Data: A Guide to the S Language  by John Chambers
* [https://www.amazon.com/Extending-Chapman-Hall-John-Chambers/dp/1498775713 Extending R] by John M. Chambers, 2016
* https://www.rmetrics.org/files/Meielisalp2009/Presentations/Chalabi1.pdf
* [https://njtierney.github.io/r/missing%20data/rbloggers/2016/11/06/simple-s3-methods/ A Simple Guide to S3 Methods]
* [https://rstudio-education.github.io/hopr/s3.html Hands-On Programming with R] by Garrett Grolemund
* https://www.stat.auckland.ac.nz/S-Workshop/Gentleman/S4Objects.pdf
* [http://cran.r-project.org/web/packages/packS4/index.html packS4: Toy Example of S4 Package], * [https://cran.r-project.org/doc/contrib/Genolini-S4tutorialV0-5en.pdf A (Not So) Short Introduction to S4]
* http://www.cyclismo.org/tutorial/R/s4Classes.html
* https://www.coursera.org/lecture/bioconductor/r-s4-methods-C4dNr
* https://www.bioconductor.org/help/course-materials/2013/UnderstandingRBioc2013/
* http://adv-r.had.co.nz/S4.html, http://adv-r.had.co.nz/OO-essentials.html
* [https://appsilon.com/object-oriented-programming-in-r-part-1/ Object-Oriented Programming in R (Part 1): An Introduction], [https://appsilon.com/object-oriented-programming-in-r-part-2/ Part 2: S3 Simplified]
 
=== Debug an S4 function ===
* '''showMethods('FUNCTION')'''
* '''getMethod('FUNCTION', 'SIGNATURE') ''' 
* '''debug(, signature)'''
{{Pre}}
> args(debug)
function (fun, text = "", condition = NULL, signature = NULL)
 
> library(genefilter) # Bioconductor
> showMethods("nsFilter")
Function: nsFilter (package genefilter)
eset="ExpressionSet"
> debug(nsFilter, signature="ExpressionSet")
 
library(DESeq2)
showMethods("normalizationFactors") # show the object class
                                    # "DESeqDataSet" in this case.
getMethod(`normalizationFactors`, "DESeqDataSet") # get the source code
</pre>
See the [https://github.com/mikelove/DESeq2/blob/445ae6c61d06de69d465b57f23e1c743d9b4537d/R/methods.R#L367 source code] of '''normalizationFactors<-''' (setReplaceMethod() is used) and the [https://github.com/mikelove/DESeq2/blob/445ae6c61d06de69d465b57f23e1c743d9b4537d/R/methods.R#L385 source code] of '''estimateSizeFactors()'''. We can see how ''avgTxLength'' was used in estimateNormFactors().
 
Another example
<pre>
<pre>
library(GSVA)
args(gsva) # function (expr, gset.idx.list, ...)
showMethods("gsva")
# Function: gsva (package GSVA)
# expr="ExpressionSet", gset.idx.list="GeneSetCollection"
# expr="ExpressionSet", gset.idx.list="list"
# expr="matrix", gset.idx.list="GeneSetCollection"
# expr="matrix", gset.idx.list="list"
# expr="SummarizedExperiment", gset.idx.list="GeneSetCollection"
# expr="SummarizedExperiment", gset.idx.list="list"
debug(gsva, signature = c(expr="matrix", gset.idx.list="list"))
# OR
# debug(gsva, signature = c("matrix", "list"))
gsva(y, geneSets, method="ssgsea", kcdf="Gaussian")
Browse[3]> debug(.gsva)
# return(ssgsea(expr, gset.idx.list, alpha = tau, parallel.sz = parallel.sz,
#      normalization = ssgsea.norm, verbose = verbose,
#      BPPARAM = BPPARAM))
isdebugged("gsva")
# [1] TRUE
undebug(gsva)
</pre>
* '''getClassDef()''' in S4 ([http://www.bioconductor.org/help/course-materials/2014/Epigenomics/BiocForSequenceAnalysis.html Bioconductor course]).
{{Pre}}
library(IRanges)
ir <- IRanges(start=c(10, 20, 30), width=5)
ir
class(ir)
## [1] "IRanges"
## attr(,"package")
## [1] "IRanges"
getClassDef(class(ir))
## Class "IRanges" [package "IRanges"]
##
## Slots:
##                                                                     
## Name:            start          width          NAMES    elementType
## Class:        integer        integer characterORNULL      character
##                                     
## Name:  elementMetadata        metadata
## Class: DataTableORNULL            list
##
## Extends:
## Class "Ranges", directly
## Class "IntegerList", by class "Ranges", distance 2
## Class "RangesORmissing", by class "Ranges", distance 2
## Class "AtomicList", by class "Ranges", distance 3
## Class "List", by class "Ranges", distance 4
## Class "Vector", by class "Ranges", distance 5
## Class "Annotated", by class "Ranges", distance 6
##
## Known Subclasses: "NormalIRanges"
</pre>
=== Check if a function is an S4 method ===
'''isS4(foo)'''
=== How to access the slots of an S4 object ===
* @ will let you access the slots of an S4 object.
* Note that often the best way to do this is to not access the slot directly but rather through an accessor function (e.g. coefs() rather than digging out the coefficients with $ or @). However, often such functions do not exist so you have to access the slots directly. This will mean that your code breaks if the internal implementation changes, however.
* [https://kasperdanielhansen.github.io/genbioconductor/html/R_S4.html#slots-and-accessor-functions R - S4 Classes and Methods] Hansen. '''getClass()''' or '''getClassDef()'''.
=== setReplaceMethod() ===
* [https://stackoverflow.com/a/24253311 What's the difference between setMethod(“$<-”) and set setReplaceMethod(“$”)?]
* [https://stackoverflow.com/a/49267668 What is setReplaceMethod() and how does it work?]
=== See what methods work on an object ===
see what methods work on an object, e.g. a GRanges object:
<pre>
methods(class="GRanges")
</pre>
Or if you have an object, x:
<pre>
methods(class=class(x))
</pre>
=== View S3 function definition: double colon '::' and triple colon ':::' operators and getAnywhere() ===
?":::"
* pkg::name returns the value of the exported variable name in namespace pkg
* pkg:::name returns the value of the internal variable name
<pre>
base::"+"
stats:::coef.default
predict.ppr
# Error: object 'predict.ppr' not found
stats::predict.ppr
# Error: 'predict.ppr' is not an exported object from 'namespace:stats'
stats:::predict.ppr  # OR 
getS3method("predict", "ppr")
getS3method("t", "test")
</pre>
[https://stackoverflow.com/a/19226817 methods() + getAnywhere() functions]
=== Read the source code (include Fortran/C, S3 and S4 methods) ===
* [https://github.com/jimhester/lookup#readme lookup] package
* [https://blog.r-hub.io/2019/05/14/read-the-source/ Read the source]
* Find the source code in [https://stackoverflow.com/a/19226817 UseMethod("XXX")] for S3 methods.
=== S3 method is overwritten ===
For example, the select() method from dplyr is overwritten by [https://github.com/cran/grpreg/blob/master/NAMESPACE grpreg] package.
An easy solution is to load grpreg before loading dplyr.
* https://stackoverflow.com/a/14407095
* [https://njtierney.github.io/r/missing%20data/rbloggers/2016/11/06/simple-s3-methods/ A Simple Guide to S3 Methods] and [https://github.com/njtierney/A-Simple-Guide-to-S3-Methods/blob/master/SimpleS3.Rmd its source]
* [https://developer.r-project.org/Blog/public/2019/08/19/s3-method-lookup/index.html S3 Method Lookup]
=== mcols() and DataFrame() from Bioc [http://bioconductor.org/packages/release/bioc/html/S4Vectors.html S4Vectors] package ===
* mcols: Get or set the metadata columns.
* colData: SummarizedExperiment instances from GenomicRanges
* DataFrame: The DataFrame class extends the DataTable virtual class and supports the storage of any type of object (with length and [ methods) as columns.
For example, in [http://www-huber.embl.de/DESeq2paper/vignettes/posterior.pdf Shrinkage of logarithmic fold changes] vignette of the DESeq2paper package
{{Pre}}
> mcols(ddsNoPrior[genes, ])
DataFrame with 2 rows and 21 columns
  baseMean  baseVar  allZero dispGeneEst    dispFit dispersion  dispIter dispOutlier  dispMAP
  <numeric> <numeric> <logical>  <numeric>  <numeric>  <numeric> <numeric>  <logical> <numeric>
1  163.5750  8904.607    FALSE  0.06263141 0.03862798  0.0577712        7      FALSE 0.0577712
2  175.3883 59643.515    FALSE  2.25306109 0.03807917  2.2530611        12        TRUE 1.6011440
  Intercept strain_DBA.2J_vs_C57BL.6J SE_Intercept SE_strain_DBA.2J_vs_C57BL.6J WaldStatistic_Intercept
  <numeric>                <numeric>    <numeric>                    <numeric>              <numeric>
1  6.210188                  1.735829    0.1229354                    0.1636645              50.515872
2  6.234880                  1.823173    0.6870629                    0.9481865                9.074686
  WaldStatistic_strain_DBA.2J_vs_C57BL.6J WaldPvalue_Intercept WaldPvalue_strain_DBA.2J_vs_C57BL.6J
                                <numeric>            <numeric>                            <numeric>
1                                10.60602        0.000000e+00                        2.793908e-26
2                                1.92280        1.140054e-19                        5.450522e-02
  betaConv  betaIter  deviance  maxCooks
  <logical> <numeric> <numeric> <numeric>
1      TRUE        3  210.4045 0.2648753
2      TRUE        9  243.7455 0.3248949
</pre>
== Pipe ==
<ul>
<li>[https://www.tidyverse.org/blog/2023/04/base-vs-magrittr-pipe/ Differences between the base R and magrittr pipes] 4/21/2023
<li>[https://win-vector.com/2020/12/05/r-is-getting-an-official-pipe-operator/ R is Getting an Official Pipe Operator], [https://win-vector.com/2020/12/07/my-opinion-on-rs-upcoming-pipe/ My Opinion on R’s Upcoming Pipe]
<li> a(b(x)) vs '''x |> b() |> a()'''. See [https://twitter.com/henrikbengtsson/status/1335328090390597632 this tweet] in R-dev 2020-12-04.
<pre>
e0 <- quote(a(b(x)))
e1 <- quote(x |> b() |> a())
identical(e0, e1)
</pre>
</li>
<li>
[https://selbydavid.com/2021/05/18/pipes/ There are now 3 different R pipes]
</li>
<li>[https://stackoverflow.com/a/67629310 Error: The pipe operator requires a function call as RHS].
<pre>
# native pipe
foo |> bar()
# magrittr pipe
foo %>% bar
</pre>
</li>
<li>[https://www.infoworld.com/article/3621369/use-the-new-r-pipe-built-into-r-41.html Use the new R pipe built into R 4.1] </li>
<li>[https://towardsdatascience.com/the-new-native-pipe-operator-in-r-cbc5fa8a37bd The New Native Pipe Operator in R] </li>
<li>[https://ivelasq.rbind.io/blog/understanding-the-r-pipe/ Understanding the native R pipe |> ] </li>
<li>[https://medium.com/number-around-us/navigating-the-data-pipes-an-r-programming-journey-with-mario-bros-1aa621af1926 Navigating the Data Pipes: An R Programming Journey with Mario Bros]
</ul>
Packages take advantage of pipes
<ul>
<li>[https://cran.r-project.org/web/packages/rstatix/index.html rstatix]: Pipe-Friendly Framework for Basic Statistical Tests
</ul>
== findInterval() ==
Related functions are cuts() and split(). See also
* [http://books.google.com/books?id=oKY5QeSWb4cC&pg=PT310&lpg=PT310&dq=r+findinterval3&source=bl&ots=YjNMkHrTMw&sig=y_wIA1um420xVCI5IoGivABge-s&hl=en&sa=X&ei=gm_yUrSqLKXesAS2_IGoBQ&ved=0CFIQ6AEwBTgo#v=onepage&q=r%20findinterval3&f=false R Graphs Cookbook]
* [http://adv-r.had.co.nz/Rcpp.html Hadley Wickham]
== Assign operator ==
* Earlier versions of R used underscore (_) as an assignment operator.
* [https://developer.r-project.org/equalAssign.html Assignments with the = Operator]
* In R 1.8.0 (2003), the assign operator has been removed. See [https://cran.r-project.org/src/base/NEWS.1 NEWS].
* In R 1.9.0 (2004), "_" is allowed in valid names. See [https://cran.r-project.org/src/base/NEWS.1 NEWS].
: [[File:R162.png|200px]]
== Operator precedence ==
The ':' operator has higher precedence than '-' so 0:N-1 evaluates to (0:N)-1, not 0:(N-1) like you probably wanted.
== order(), rank() and sort() ==
If we want to find the indices of the first 25 genes with the smallest p-values, we can use '''order(pval)[1:25]'''.
<pre>
> x = sample(10)
> x
[1]  4  3 10  7  5  8  6  1  9  2
> order(x)
[1]  8 10  2  1  5  7  4  6  9  3
> rank(x)
[1]  4  3 10  7  5  8  6  1  9  2
> rank(10*x)
[1]  4  3 10  7  5  8  6  1  9  2
> x[order(x)]
[1]  1  2  3  4  5  6  7  8  9 10
> sort(x)
[1]  1  2  3  4  5  6  7  8  9 10
</pre>
=== relate order() and rank() ===
<ul>
<li>Order to rank: rank() = order(order())
<syntaxhighlight lang='r'>
set.seed(1)
x <- rnorm(5)
order(x)
# [1] 3 1 2 5 4
rank(x)
# [1] 2 3 1 5 4
order(order(x))
# [1] 2 3 1 5 4
all(rank(x) == order(order(x)))
# TRUE
</syntaxhighlight>
<li>Order to Rank method 2: rank(order()) = 1:n
<syntaxhighlight lang='r'>
ord <- order(x)
ranks <- integer(length(x))
ranks[ord] <- seq_along(x)
ranks
# [1] 2 3 1 5 4
</syntaxhighlight>
<li>Rank to Order:
<syntaxhighlight lang='r'>
ranks <- rank(x)
ord <- order(ranks)
ord
# [1] 3 1 2 5 4
</syntaxhighlight>
</ul>
=== OS-dependent results on sorting string vector ===
Gene symbol case.
<pre>
# mac:
order(c("DC-UbP", "DC2")) # c(1,2)
# linux:
order(c("DC-UbP", "DC2")) # c(2,1)
</pre>
Affymetric id case.
<pre>
# mac:
order(c("202800_at", "2028_s_at")) # [1] 2 1
sort(c("202800_at", "2028_s_at")) # [1] "2028_s_at" "202800_at"
# linux
order(c("202800_at", "2028_s_at")) # [1] 1 2
sort(c("202800_at", "2028_s_at")) # [1] "202800_at" "2028_s_at"
</pre>
It does not matter if we include factor() on the character vector.
The difference is related to locale. See
* [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/locales ?locales] in R
* On OS, type '''locale'''
* [https://stackoverflow.com/questions/39171613/sort-produces-different-results-in-ubuntu-and-windows sort() produces different results in Ubuntu and Windows]
* To fix the inconsistency problem, we can set the locale in R code to "C" or use the stringr package (the locale is part of [https://www.rdocumentation.org/packages/stringr/versions/1.4.0/topics/str_order str_order()]'s arguments).
<pre>
# both mac and linux
stringr::str_order(c("202800_at", "2028_s_at")) # [1] 2 1
stringr::str_order(c("DC-UbP", "DC2")) # [1] 1 2
# Or setting the locale to "C"
Sys.setlocale("LC_ALL", "C"); sort(c("DC-UbP", "DC2"))
# Or
Sys.setlocale("LC_COLLATE", "C"); sort(c("DC-UbP", "DC2"))
# But not
Sys.setlocale("LC_ALL", "en_US.UTF-8"); sort(c("DC-UbP", "DC2"))
</pre>
=== unique() ===
It seems it does not sort. [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/unique ?unique].
<pre>
# mac & linux
R> unique(c("DC-UbP", "DC2"))
[1] "DC-UbP" "DC2"
</pre>
== do.call ==
'''do.call''' constructs and executes a function call from a name or a function and a list of arguments to be passed to it.
[https://www.r-bloggers.com/2023/05/the-do-call-function-in-r-unlocking-efficiency-and-flexibility/ The do.call() function in R: Unlocking Efficiency and Flexibility]
Below are some examples from the [https://stat.ethz.ch/R-manual/R-devel/library/base/html/do.call.html help].
* Usage
{{Pre}}
do.call(what, args, quote = FALSE, envir = parent.frame())
# what: either a function or a non-empty character string naming the function to be called.
# args: a list of arguments to the function call. The names attribute of args gives the argument names.
# quote: a logical value indicating whether to quote the arguments.
# envir: an environment within which to evaluate the call. This will be most useful
#        if what is a character string and the arguments are symbols or quoted expressions.
</pre>
* do.call() is similar to [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/lapply lapply()] but not the same. It seems do.call() can make a simple function vectorized.
{{Pre}}
> do.call("complex", list(imag = 1:3))
[1] 0+1i 0+2i 0+3i
> lapply(list(imag = 1:3), complex)
$imag
[1] 0+0i
> complex(imag=1:3)
[1] 0+1i 0+2i 0+3i
> do.call(function(x) x+1, list(1:3))
[1] 2 3 4
</pre>
* Applying do.call with Multiple Arguments
<pre>
> do.call("sum", list(c(1,2,3,NA), na.rm = TRUE))
[1] 6
> do.call("sum", list(c(1,2,3,NA) ))
[1] NA
</pre>
* [https://www.stat.berkeley.edu/~s133/Docall.html do.call() allows you to call any R function, but instead of writing out the arguments one by one, you can use a list to hold the arguments of the function.]
{{Pre}}
> tmp <- expand.grid(letters[1:2], 1:3, c("+", "-"))
> length(tmp)
[1] 3
> tmp[1:4,]
  Var1 Var2 Var3
1    a    1    +
2    b    1    +
3    a    2    +
4    b    2    +
> c(tmp, sep = "")
$Var1
[1] a b a b a b a b a b a b
Levels: a b
$Var2
[1] 1 1 2 2 3 3 1 1 2 2 3 3
$Var3
[1] + + + + + + - - - - - -
Levels: + -
$sep
[1] ""
> do.call("paste", c(tmp, sep = ""))
[1] "a1+" "b1+" "a2+" "b2+" "a3+" "b3+" "a1-" "b1-" "a2-" "b2-" "a3-"
[12] "b3-"
</pre>
* ''environment'' and ''quote'' arguments.
{{Pre}}
> A <- 2
> f <- function(x) print(x^2)
> env <- new.env()
> assign("A", 10, envir = env)
> assign("f", f, envir = env)
> f <- function(x) print(x)
> f(A) 
[1] 2
> do.call("f", list(A))
[1] 2
> do.call("f", list(A), envir = env) 
[1] 4
> do.call(f, list(A), envir = env) 
[1] 2                      # Why?
> eval(call("f", A))                     
[1] 2
> eval(call("f", quote(A)))             
[1] 2
> eval(call("f", A), envir = env)       
[1] 4
> eval(call("f", quote(A)), envir = env) 
[1] 100
</pre>
* Good use case; see [https://stackoverflow.com/a/11892680 Get all Parameters as List]
{{Pre}}
> foo <- function(a=1, b=2, ...) {
        list(arg=do.call(c, as.list(match.call())[-1]))
  }
> foo()
$arg
NULL
> foo(a=1)
$arg
a
1
> foo(a=1, b=2, c=3)
$arg
a b c
1 2 3
</pre>
* do.call() + switch(). See [https://github.com/satijalab/seurat/blob/13b615c27eeeac85e5c928aa752197ac224339b9/R/preprocessing.R#L2450 an example] from Seurat::NormalizeData.
<pre>
do.call(
  what = switch(
    EXPR = margin,
    '1' = 'rbind',
    '2' = 'cbind',
    stop("'margin' must be 1 or 2")
  ),
  args = normalized.data
)
switch('a', 'a' = rnorm(3), 'b'=rnorm(4)) # switch returns a value
do.call(switch('a', 'a' = 'rnorm', 'b'='rexp'), args=list(n=4)) # switch returns a function
</pre>
* The function we want to call is a string that may change: [https://github.com/cran/glmnet/blob/master/R/cv.glmnet.raw.R#L66 glmnet]
<pre>
# Suppose we want to call cv.glmnet or cv.coxnet or cv.lognet or cv.elnet .... depending on the case
fun = paste("cv", subclass, sep = ".")
cvstuff = do.call(fun, list(predmat,y,type.measure,weights,foldid,grouped))
</pre>
=== expand.grid, mapply, vapply ===
[https://shikokuchuo.net/posts/10-combinations/ A faster way to generate combinations for mapply and vapply]
=== do.call vs mapply ===
* do.call() is doing what [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/mapply mapply()] does but do.call() uses a list instead of multiple arguments. So do.call() more close to [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/funprog base::Map()] function.
{{Pre}}
> mapply(paste, tmp[1], tmp[2], tmp[3], sep = "")
      Var1
[1,] "a1+"
[2,] "b1+"
[3,] "a2+"
[4,] "b2+"
[5,] "a3+"
[6,] "b3+"
[7,] "a1-"
[8,] "b1-"
[9,] "a2-"
[10,] "b2-"
[11,] "a3-"
[12,] "b3-"
# It does not work if we do not explicitly specify the arguments in mapply()
> mapply(paste, tmp, sep = "")
      Var1 Var2 Var3
[1,] "a"  "1"  "+"
[2,] "b"  "1"  "+"
[3,] "a"  "2"  "+"
[4,] "b"  "2"  "+"
[5,] "a"  "3"  "+"
[6,] "b"  "3"  "+"
[7,] "a"  "1"  "-"
[8,] "b"  "1"  "-"
[9,] "a"  "2"  "-"
[10,] "b"  "2"  "-"
[11,] "a"  "3"  "-"
[12,] "b"  "3"  "-"
</pre>
* mapply is useful in generating variables with a vector of parameters. For example suppose we want to generate variables from exponential/weibull distribution and a vector of scale parameters (depending on some covariates). In this case we can use ([https://stackoverflow.com/a/17031993 Simulating Weibull distributions from vectors of parameters in R])
{{Pre}}
set.seed(1)
mapply(rweibull, 1, c(1, 10), MoreArgs=list(n=1))
# [1] 1.326108 9.885284
set.seed(1)
x <- replicate(1000, mapply(rweibull, 1, c(1, 10), MoreArgs=list(n=1)))
dim(x) # [1]  2 1000
rowMeans(x)
# [1]  1.032209 10.104131
</pre>
{{Pre}}
set.seed(1); Vectorize(rweibull)(n=1, shape=1, scale=c(1, 10))
# [1] 1.326108 9.885284
set.seed(1); x <- replicate(1000, Vectorize(rweibull)(n=1, shape=1, scale=c(1, 10)))
</pre>
=== do.call vs lapply ===
[https://stackoverflow.com/a/10801883 What's the difference between lapply and do.call?] It seems to me the best usage is combining both functions: '''do.call(..., lapply())'''
* lapply returns a list of the same length as X, each element of which is the result of applying FUN to the corresponding element of X.
* do.call constructs and executes a function call from a name or a function and a list of arguments to be passed to it. '''It is widely used, for example, to assemble lists into simpler structures (often with rbind or cbind).'''
* Map applies a function to the corresponding elements of given vectors... Map is a simple wrapper to mapply which does not attempt to simplify the result, similar to Common Lisp's mapcar (with arguments being recycled, however). Future versions may allow some control of the result type.
{{Pre}}
> lapply(iris, class) # same as Map(class, iris)
$Sepal.Length
[1] "numeric"
$Sepal.Width
[1] "numeric"
$Petal.Length
[1] "numeric"
$Petal.Width
[1] "numeric"
$Species
[1] "factor"
> x <- lapply(iris, class)
> do.call(c, x)
Sepal.Length  Sepal.Width Petal.Length  Petal.Width      Species
  "numeric"    "numeric"    "numeric"    "numeric"    "factor"
</pre>
https://stackoverflow.com/a/10801902
* '''lapply''' applies a function '''over a list'''. So there will be several function calls.
* '''do.call''' calls a function with '''a list of arguments''' (... argument) such as [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/c c()] or [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/cbind rbind()/cbind()] or [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/sum sum] or [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/order order] or [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/Extract "["] or paste. So there is only one function call.
{{Pre}}
> X <- list(1:3,4:6,7:9)
> lapply(X,mean)
[[1]]
[1] 2
[[2]]
[1] 5
[[3]]
[1] 8
> do.call(sum, X)
[1] 45
> sum(c(1,2,3), c(4,5,6), c(7,8,9))
[1] 45
> do.call(mean, X) # Error
> do.call(rbind,X)
    [,1] [,2] [,3]
[1,]    1    2    3
[2,]    4    5    6
[3,]    7    8    9
> lapply(X,rbind)
[[1]]
    [,1] [,2] [,3]
[1,]    1    2    3
[[2]]
    [,1] [,2] [,3]
[1,]    4    5    6
[[3]]
    [,1] [,2] [,3]
[1,]    7    8    9
> mapply(mean, X, trim=c(0,0.5,0.1))
[1] 2 5 8
> mapply(mean, X)
[1] 2 5 8
</pre>
Below is a good example to show the difference of lapply() and do.call() - [https://stackoverflow.com/a/42734863 Generating Random Strings].
{{Pre}}
> set.seed(1)
> x <- replicate(2, sample(LETTERS, 4), FALSE)
> x
[[1]]
[1] "Y" "D" "G" "A"
[[2]]
[1] "B" "W" "K" "N"
> lapply(x, paste0)
[[1]]
[1] "Y" "D" "G" "A"
[[2]]
[1] "B" "W" "K" "N"
> lapply(x, paste0, collapse= "")
[[1]]
[1] "YDGA"
[[2]]
[1] "BWKN"
> do.call(paste0, x)
[1] "YB" "DW" "GK" "AN"
</pre>
=== do.call + rbind + lapply ===
Lots of examples. See for example [https://stat.ethz.ch/pipermail/r-help/attachments/20140423/62d8d103/attachment.pl this one] for creating a data frame from a vector.
{{Pre}}
x <- readLines(textConnection("---CLUSTER 1 ---
3
4
5
6
---CLUSTER 2 ---
9
10
8
11"))
# create a list of where the 'clusters' are
clust <- c(grep("CLUSTER", x), length(x) + 1L)
# get size of each cluster
clustSize <- diff(clust) - 1L
# get cluster number
clustNum <- gsub("[^0-9]+", "", x[grep("CLUSTER", x)])
result <- do.call(rbind, lapply(seq(length(clustNum)), function(.cl){
    cbind(Object = x[seq(clust[.cl] + 1L, length = clustSize[.cl])]
        , Cluster = .cl
        )
    }))
result
    Object Cluster
[1,] "3"    "1"
[2,] "4"    "1"
[3,] "5"    "1"
[4,] "6"    "1"
[5,] "9"    "2"
[6,] "10"  "2"
[7,] "8"    "2"
[8,] "11"  "2"
</pre>
A 2nd example is to [http://datascienceplus.com/working-with-data-frame-in-r/ sort a data frame] by using do.call(order, list()).
Another example is to reproduce aggregate(). aggregate() = do.call() + by().
{{Pre}}
attach(mtcars)
do.call(rbind, by(mtcars, list(cyl, vs), colMeans))
# the above approach give the same result as the following
# except it does not have an extra Group.x columns
aggregate(mtcars, list(cyl, vs), FUN=mean)
</pre>
== Run examples ==
When we call help(FUN), it shows the document in the browser. The browser will show
<pre>
example(FUN, package = "XXX") was run in the console
To view output in the browser, the knitr package must be installed
</pre>
== How to get examples from help file, example() ==
[https://blog.r-hub.io/2020/01/27/examples/ Code examples in the R package manuals]:
<pre>
# How to run all examples from a man page
example(within)
# How to check your examples?
devtools::run_examples()
testthat::test_examples()
</pre>
See [https://stat.ethz.ch/pipermail/r-help/2014-April/369342.html this post].
Method 1:
<pre>
example(acf, give.lines=TRUE)
</pre>
Method 2:
<pre>
Rd <- utils:::.getHelpFile(?acf)
tools::Rd2ex(Rd)
</pre>
== "[" and "[[" with the sapply() function ==
Suppose we want to extract string from the id like "ABC-123-XYZ" before the first hyphen.
<pre>
sapply(strsplit("ABC-123-XYZ", "-"), "[", 1)
</pre>
is the same as
<pre>
sapply(strsplit("ABC-123-XYZ", "-"), function(x) x[1])
</pre>
== Dealing with dates ==
<ul>
<li>Simple examples
<syntaxhighlight lang='rsplus'>
dates <- c("January 15, 2023", "December 31, 1999")
date_objects <- as.Date(dates, format = "%B %d, %Y") # format is for the input
# [1] "2023-01-15" "1999-12-31"
</syntaxhighlight>
<li>Find difference
<syntaxhighlight lang='rsplus'>
# Convert the dates to Date objects
date1 <- as.Date("6/29/21", format="%m/%d/%y")
date2 <- as.Date("11/9/21", format="%m/%d/%y")
# Calculate the difference in days
diff_days <- as.numeric(difftime(date2, date1, units="days")) # 133
# In months
diff_days / (365.25/12)  # 4.36961 
# OR using the lubridate package
library(lubridate)
# Convert the dates to Date objects
date1 <- mdy("6/29/21")
date2 <- mdy("11/9/21")
interval(date1, date2) %/% months(1)
</syntaxhighlight>
<li>http://cran.r-project.org/web/packages/lubridate/vignettes/lubridate.html
<syntaxhighlight lang='rsplus'>
d1 = date()
class(d1) # "character"
d2 = Sys.Date()
class(d2) # "Date"
format(d2, "%a %b %d")
library(lubridate); ymd("20140108") # "2014-01-08 UTC"
mdy("08/04/2013") # "2013-08-04 UTC"
dmy("03-04-2013") # "2013-04-03 UTC"
ymd_hms("2011-08-03 10:15:03") # "2011-08-03 10:15:03 UTC"
ymd_hms("2011-08-03 10:15:03", tz="Pacific/Auckland")
# "2011-08-03 10:15:03 NZST"
?Sys.timezone
x = dmy(c("1jan2013", "2jan2013", "31mar2013", "30jul2013"))
wday(x[1]) # 3
wday(x[1], label=TRUE) # Tues
</syntaxhighlight>
<li>http://www.r-statistics.com/2012/03/do-more-with-dates-and-times-in-r-with-lubridate-1-1-0/
<li>http://rpubs.com/seandavi/GEOMetadbSurvey2014
<li>We want our dates and times as class "Date" or the class "POSIXct", "POSIXlt". For more information type ?POSIXlt.
<li>[https://cran.r-project.org/web/packages/anytime/index.html anytime] package
<li>weeks to Christmas difftime(as.Date(“2019-12-25”), Sys.Date(), units =“weeks”)
<li>[https://blog.rsquaredacademy.com/handling-date-and-time-in-r/ A Comprehensive Introduction to Handling Date & Time in R] 2020
<li>[https://www.spsanderson.com/steveondata/posts/rtip-2023-05-12/index.html Working with Dates and Times Pt 1]
* Three major functions: as.Date(), as.POSIXct(), and as.POSIXlt().
* '''POSIXct''' is a class in R that represents date-time data. The ct stands for “calendar time” and it represents the (signed) number of seconds since the beginning of 1970 as a numeric vector1.  '''It stores date time as integer.'''
* '''POSIXlt''' is a class in R that represents date-time data. It stands for “local time” and is a list with components as integer vectors, which can represent a vector of broken-down times. '''It stores date time as list:sec, min, hour, mday, mon, year, wday, yday, isdst, zone, gmtoff'''.
<li>[https://www.r-bloggers.com/2023/11/r-lubridate-how-to-efficiently-work-with-dates-and-times-in-r/ R lubridate: How To Efficiently Work With Dates and Times in R] 2023
</ul>
== Nonstandard/non-standard evaluation, deparse/substitute and scoping ==
* [https://www.brodieg.com/2020/05/05/on-nse/ Standard and Non-Standard Evaluation in R]
* [http://adv-r.had.co.nz/Computing-on-the-language.html Nonstandard evaluation] from Advanced R book.
* [https://edwinth.github.io/blog/nse/ Non-standard evaluation, how tidy eval builds on base R]
* [https://cran.r-project.org/web/packages/lazyeval/vignettes/lazyeval.html Vignette] from the [https://cran.r-project.org/web/packages/lazyeval/index.html lazyeval] package. It is needed in three cases
** Labelling: turn an argument into a label
** Formulas
** Dot-dot-dot
* [https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/substitute substitute(expr, env)] - capture expression. The return mode is a '''call'''.
** substitute() is often paired with '''deparse'''() to create informative labels for data sets and plots. The return mode of deparse() is '''character strings'''.
** Use 'substitute' to include the variable's name in a plot title, e.g.: '''var <- "abc"; hist(var,main=substitute(paste("Dist of ", var))) ''' will show the title "Dist of var" instead of "Dist of abc" in the title.
** [https://stackoverflow.com/a/34079727 Passing a variable name to a function in R]
** Example:
::<syntaxhighlight lang='rsplus'>
f <- function(x) {
  substitute(x)
}
f(1:10)
# 1:10
class(f(1:10)) # or mode()
# [1] "call"
g <- function(x) deparse(substitute(x))
g(1:10)
# [1] "1:10"
class(g(1:10)) # or mode()
# [1] "character"
</syntaxhighlight>
* quote(expr) - similar to substitute() but do nothing?? [https://www.rdocumentation.org/packages/base/versions/3.5.2/topics/noquote noquote] - print character strings without quotes
:<syntaxhighlight lang='rsplus'>
mode(quote(1:10))
# [1] "call"
</syntaxhighlight>
* eval(expr, envir), evalq(expr, envir) - eval evaluates its first argument in the current scope before passing it to the evaluator: evalq avoids this.
** The '''parent.frame()''' is necessary in cases like the [https://www.rdocumentation.org/packages/stats/versions/3.6.2/topics/update stats::update()] function used by [https://github.com/cran/glmnet/blob/master/R/relax.glmnet.R#L66 relax.glmnet()].
** Example:
::<syntaxhighlight lang='rsplus'>
sample_df <- data.frame(a = 1:5, b = 5:1, c = c(5, 3, 1, 4, 1))
subset1 <- function(x, condition) {
  condition_call <- substitute(condition)
  r <- eval(condition_call, x)
  x[r, ]
}
x <- 4
condition <- 4
subset1(sample_df, a== 4) # same as subset(sample_df, a >= 4)
subset1(sample_df, a== x) # WRONG!
subset1(sample_df, a == condition) # ERROR
subset2 <- function(x, condition) {
  condition_call <- substitute(condition)
  r <- eval(condition_call, x, parent.frame())
  x[r, ]
}
subset2(sample_df, a == 4) # same as subset(sample_df, a >= 4)
subset2(sample_df, a == x) # 👌
subset2(sample_df, a == condition) # 👍
</syntaxhighlight>
* deparse(expr) - turns unevaluated expressions into character strings. For example,
:<syntaxhighlight lang='rsplus'>
> deparse(args(lm))
[1] "function (formula, data, subset, weights, na.action, method = \"qr\", "
[2] "    model = TRUE, x = FALSE, y = FALSE, qr = TRUE, singular.ok = TRUE, "
[3] "    contrasts = NULL, offset, ...) "                                   
[4] "NULL"   
> deparse(args(lm), width=20)
[1] "function (formula, data, "        "    subset, weights, "         
[3] "    na.action, method = \"qr\", " "    model = TRUE, x = FALSE, " 
[5] "    y = FALSE, qr = TRUE, "      "    singular.ok = TRUE, "       
[7] "    contrasts = NULL, "          "    offset, ...) "             
[9] "NULL"
</syntaxhighlight>
* parse(text) - returns the parsed but unevaluated expressions in a list. See [[R#Create_a_Simple_Socket_Server_in_R|Create a Simple Socket Server in R]] for the application of '''eval(parse(text))'''. Be cautious!
** [http://r.789695.n4.nabble.com/using-eval-parse-paste-in-a-loop-td849207.html eval(parse...)) should generally be avoided]
** [https://stackoverflow.com/questions/13649979/what-specifically-are-the-dangers-of-evalparse What specifically are the dangers of eval(parse(…))?]
Following is another example. Assume we have a bunch of functions (f1, f2, ...; each function implements a different algorithm) with same input arguments format (eg a1, a2). We like to run these function on the same data (to compare their performance).
{{Pre}}
f1 <- function(x) x+1; f2 <- function(x) x+2; f3 <- function(x) x+3
f1(1:3)
f2(1:3)
f3(1:3)
# Or
myfun <- function(f, a) {
    eval(parse(text = f))(a)
}
myfun("f1", 1:3)
myfun("f2", 1:3)
myfun("f3", 1:3)
# Or with lapply
method <- c("f1", "f2", "f3")
res <- lapply(method, function(M) {
                    Mres <- eval(parse(text = M))(1:3)
                    return(Mres)
})
names(res) <- method
</pre>
=== library() accept both quoted and unquoted strings ===
[https://stackoverflow.com/a/25210607 How can library() accept both quoted and unquoted strings]. The key lines are
<pre>
  if (!character.only)
    package <- as.character(substitute(package))
</pre>
=== Lexical scoping ===
* [https://lgreski.github.io/dsdepot/2020/06/28/rObjectsSObjectsAndScoping.html R Objects, S Objects, and Lexical Scoping]
* [http://www.biostat.jhsph.edu/~rpeng/docs/R-classes-scope.pdf#page=31 Dynamic scoping vs Lexical scoping] and the example of [http://www.biostat.jhsph.edu/~rpeng/docs/R-classes-scope.pdf#page=41 optimization]
* [https://www.r-bloggers.com/2024/03/indicating-local-functions-in-r-scripts/ Indicating local functions in R scripts]
== The ‘…’ argument ==
* See [http://cran.r-project.org/doc/manuals/R-intro.html#The-three-dots-argument Section 10.4 of An Introduction to R]. Especially, the expression '''list(...)''' evaluates all such arguments and returns them in a named list
* [https://statisticaloddsandends.wordpress.com/2020/11/15/some-notes-when-using-dot-dot-dot-in-r/ Some notes when using dot-dot-dot (…) in R]
* [https://stackoverflow.com/questions/26684509/how-to-check-if-any-arguments-were-passed-via-ellipsis-in-r-is-missing How to check if any arguments were passed via “…” (ellipsis) in R? Is missing(…) valid?]
== Functions ==
* https://adv-r.hadley.nz/functions.html
* [https://towardsdatascience.com/writing-better-r-functions-best-practices-and-tips-d48ef0691c24 Writing Better R Functions — Best Practices and Tips]. The [https://cran.r-project.org/web/packages/docstring/index.html docstring] package and "?" is interesting!
=== Function argument ===
[https://cran.r-project.org/doc/manuals/r-release/R-lang.html#Argument-matching Argument matching] from [https://cran.r-project.org/doc/manuals/r-release/R-lang.html R Language Definition] manual.
Argument matching is augmented by the functions
* [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/match.arg match.arg],
* [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/match.call match.call]
* [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/match.fun match.fun].
Access to the partial matching algorithm used by R is via [https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/pmatch pmatch].
=== Check function arguments ===
[https://blog.r-hub.io/2022/03/10/input-checking/ Checking the inputs of your R functions]: '''match.arg()''' , '''stopifnot()'''
'''stopifnot()''': function argument sanity check
<ul>
<li>[https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/stopifnot stopifnot()]. ''stopifnot'' is a quick way to check multiple conditions on the input. so for instance. The code stops when either of the three conditions are not satisfied. However, it doesn't produce pretty error messages.
<pre>
stopifnot(condition1, condition2, ...)
</pre>
</li>
<li>[https://rud.is/b/2020/05/19/mining-r-4-0-0-changelog-for-nuggets-of-gold-1-stopifnot/ Mining R 4.0.0 Changelog for Nuggets of Gold] </li>
</ul>
=== Lazy evaluation in R functions arguments ===
* http://adv-r.had.co.nz/Functions.html
* https://stat.ethz.ch/pipermail/r-devel/2015-February/070688.html
* https://twitter.com/_wurli/status/1451459394009550850
'''R function arguments are lazy — they’re only evaluated if they’re actually used'''.
* Example 1. By default, R function arguments are lazy.
<pre>
f <- function(x) {
  999
}
f(stop("This is an error!"))
#> [1] 999
</pre>
* Example 2. If you want to ensure that an argument is evaluated you can use '''force()'''.
<pre>
add <- function(x) {
  force(x)
  function(y) x + y
}
adders2 <- lapply(1:10, add)
adders2[[1]](10)
#> [1] 11
adders2[[10]](10)
#> [1] 20
</pre>
* Example 3. Default arguments are evaluated inside the function.
<pre>
f <- function(x = ls()) {
  a <- 1
  x
}
# ls() evaluated inside f:
f()
# [1] "a" "x"
# ls() evaluated in global environment:
f(ls())
# [1] "add"    "adders" "f"
</pre>
* Example 4. Laziness is useful in if statements — the second statement below will be evaluated only if the first is true.
<pre>
x <- NULL
if (!is.null(x) && x > 0) {
}
</pre>
=== Use of functions as arguments ===
[https://www.njtierney.com/post/2019/09/29/unexpected-function/ Just Quickly: The unexpected use of functions as arguments]
=== body() ===
[https://stackoverflow.com/a/51548945 Remove top axis title base plot]
=== Return functions in R ===
* [https://win-vector.com/2015/04/03/how-and-why-to-return-functions-in-r/ How and why to return functions in R]
* See the doc & example from [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/taskCallback taskCallback - Create an R-level task callback manager]. [https://developer.r-project.org/TaskHandlers.pdf Top-level Task Callbacks in R].
* [https://purrple.cat/blog/2017/05/28/turn-r-users-insane-with-evil/ Turn R users insane with evil]
=== anonymous function ===
In R, the main difference between a lambda function (also known as an anonymous function) and a regular function is that a '''lambda function is defined without a name''', while a regular function is defined with a name.
<ul>
<li>See [[Tidyverse#Anonymous_functions|Tidyverse]] page
<li>But defining functions to use them only once is kind of overkill. That's why you can use so-called anonymous functions in R. For example, '''lapply(list(1,2,3), function(x) { x * x }) '''
<li>you can use lambda functions with many other functions in R that take a function as an argument. Some examples include '''sapply, apply, vapply, mapply, Map, Reduce, Filter''', and '''Find'''. These functions all work in a similar way to lapply by applying a function to elements of a list or vector.
<pre>
Reduce(function(x, y) x*y, list(1, 2, 3, 4)) # 24
</pre>
<li>[https://coolbutuseless.github.io/2019/03/13/anonymous-functions-in-r-part-1/ purrr anonymous function]
<li>[https://towardsdatascience.com/the-new-pipe-and-anonymous-function-syntax-in-r-54d98861014c The new pipe and anonymous function syntax in R 4.1.0]
<li>[http://adv-r.had.co.nz/Functional-programming.html#anonymous-functions Functional programming] from Advanced R
<li>[https://www.projectpro.io/recipes/what-are-anonymous-functions-r What are anonymous functions in R].
<syntaxhighlight lang='rsplus'>
> (function(x) x * x)(3)
[1] 9
> (\(x) x * x)(3)
[1] 9
</syntaxhighlight>
</ul>
== Backtick sign, infix/prefix/postfix operators ==
The backtick sign ` (not the single quote) refers to functions or variables that have otherwise reserved or illegal names; e.g. '&&', '+', '(', 'for', 'if', etc. See some examples in [http://adv-r.had.co.nz/Functions.html Advanced R] and [https://stackoverflow.com/a/36229703 What do backticks do in R?].
<pre>
iris %>%  `[[`("Species")
</pre>
'''[http://en.wikipedia.org/wiki/Infix_notation infix]''' operator.
<pre>
1 + 2    # infix
+ 1 2    # prefix
1 2 +    # postfix
</pre>
Use with functions like sapply, e.g. '''sapply(1:5, `+`, 3) '''  .
== Error handling and exceptions, tryCatch(), stop(), warning() and message() ==
<ul>
<li>http://adv-r.had.co.nz/Exceptions-Debugging.html </li>
<li>[https://www.r-bloggers.com/2023/11/catch-me-if-you-can-exception-handling-in-r/ Catch Me If You Can: Exception Handling in R] </li>
<li>Temporarily disable warning messages
<pre>
# Method1:
suppressWarnings(expr)
# Method 2:
<pre>
defaultW <- getOption("warn")
options(warn = -1)
[YOUR CODE]
options(warn = defaultW)
</pre>
</li>
<li>try() allows execution to continue even after an error has occurred. You can suppress the message with '''try(..., silent = TRUE)'''.
<pre>
out <- try({
  a <- 1
  b <- "x"
  a + b
})
elements <- list(1:10, c(-1, 10), c(T, F), letters)
results <- lapply(elements, log)
is.error <- function(x) inherits(x, "try-error")
succeeded <- !sapply(results, is.error)
</pre>
</li>
<li>tryCatch(): With tryCatch() you map conditions to handlers (like switch()), named functions that are called with the condition as an input. Note that try() is a simplified version of tryCatch().
<pre>
tryCatch(expr, ..., finally)
show_condition <- function(code) {
  tryCatch(code,
    error = function(c) "error",
    warning = function(c) "warning",
    message = function(c) "message"
  )
}
show_condition(stop("!"))
#> [1] "error"
show_condition(warning("?!"))
#> [1] "warning"
show_condition(message("?"))
#> [1] "message"
show_condition(10)
#> [1] 10
</pre>
Below is another snippet from available.packages() function,
{{Pre}}
z <- tryCatch(download.file(....), error = identity)
if (!inherits(z, "error")) STATEMENTS
</pre>
</li>
<li>The return class from tryCatch() may not be fixed.
<pre>
result <- tryCatch({
  # Code that might generate an error or warning
  log(99)
}, warning = function(w) {
  # Code to handle warnings
  print(paste("Warning:", w))
}, error = function(e) {
  # Code to handle errors
  print(paste("Error:", e))
}, finally = {
  # Code to always run, regardless of whether an error or warning occurred
  print("Finished")
}) 
# character type. But if we remove 'finally', it will be numeric.
</pre>
<li>[https://www.bangyou.me/post/capture-logs/ Capture message, warnings and errors from a R function]
</li>
</ul>
=== suppressMessages() ===
suppressMessages(expression)
== List data type ==
=== Create an empty list ===
<pre>
out <- vector("list", length=3L) # OR out <- list()
for(j in 1:3) out[[j]] <- myfun(j)
outlist <- as.list(seq(nfolds))
</pre>
=== Nested list of data frames ===
An array can only hold data of a single type. read.csv() returns a data frame, which can contain both numerical and character data.
<pre>
res <- vector("list", 3)
names(res) <- paste0("m", 1:3)
for (i in seq_along(res)) {
  res[[i]] <- vector("list", 2)  # second-level list with 2 elements
  names(res[[i]]) <- c("fc", "pre")
}
res[["m1"]][["fc"]] <- read.csv()
head(res$m1$fc) # Same as res[["m1"]][["fc"]]
</pre>
=== Using $ in R on a List ===
[https://www.statology.org/dollar-sign-in-r/ How to Use Dollar Sign ($) Operator in R]
=== [http://adv-r.had.co.nz/Functions.html Calling a function given a list of arguments] ===
<pre>
> args <- list(c(1:10, NA, NA), na.rm = TRUE)
> do.call(mean, args)
[1] 5.5
> mean(c(1:10, NA, NA), na.rm = TRUE)
[1] 5.5
</pre>
=== Descend recursively through lists ===
<nowiki>x[[c(5,3)]] </nowiki> is the same as <nowiki>x[[5]][[3]]</nowiki>. See [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/Extract ?Extract].
=== Avoid if-else or switch ===
?plot.stepfun.
<pre>
y0 <- c(1,2,4,3)
sfun0  <- stepfun(1:3, y0, f = 0)
sfun.2 <- stepfun(1:3, y0, f = .2)
sfun1  <- stepfun(1:3, y0, right = TRUE)
tt <- seq(0, 3, by = 0.1)
op <- par(mfrow = c(2,2))
plot(sfun0); plot(sfun0, xval = tt, add = TRUE, col.hor = "bisque")
plot(sfun.2);plot(sfun.2, xval = tt, add = TRUE, col = "orange") # all colors
plot(sfun1);lines(sfun1, xval = tt, col.hor = "coral")
##-- This is  revealing :
plot(sfun0, verticals = FALSE,
    main = "stepfun(x, y0, f=f)  for f = 0, .2, 1")
for(i in 1:3)
  lines(list(sfun0, sfun.2, stepfun(1:3, y0, f = 1))[[i]], col = i)
legend(2.5, 1.9, paste("f =", c(0, 0.2, 1)), col = 1:3, lty = 1, y.intersp = 1)
par(op)
</pre>
[[:File:StepfunExample.svg]]
== Open a new Window device ==
X11() or dev.new()
== par() ==
?par
=== text size (cex) and font size on main, lab & axis ===
* [https://www.statmethods.net/advgraphs/parameters.html Graphical Parameters] from statmethods.net.
* [https://designdatadecisions.wordpress.com/2015/06/09/graphs-in-r-overlaying-data-summaries-in-dotplots/ Overlaying Data Summaries in Dotplots]
Examples (default is 1 for each of them):
* cex.main=0.9
* cex.sub
* cex.lab=0.8, font.lab=2 (x/y axis labels)
* cex.axis=0.8, font.axis=2 (axis/tick text/labels)
* col.axis="grey50"
An quick example to increase font size ('''cex.lab''', '''cex.axis''', '''cex.main''') and line width ('''lwd''') in a line plot and '''cex''' & '''lwd''' in the legend.
<pre>
plot(x=x$mids, y=x$density, type="l",
    xlab="p-value", ylab="Density", lwd=2,
    cex.lab=1.5, cex.axis=1.5,
    cex.main=1.5, main = "")
lines(y$mids, y$density, lty=2, pwd=2)
lines(z$mids, z$density, lty=3, pwd=2)
legend('topright',legend = c('Method A','Method B','Method C'),
      lty=c(2,1,3), lwd=c(2,2,2), cex = 1.5, xjust = 0.5, yjust = 0.5)
</pre>
ggplot2 case (default font size is [https://ggplot2.tidyverse.org/articles/faq-customising.html 11 points]):
* plot.title
* plot.subtitle
* axis.title.x, axis.title.y: (x/y axis labels)
* axis.text.x & axis.text.y: (axis/tick text/labels)
<pre>
ggplot(df, aes(x, y)) +
  geom_point() +
  labs(title = "Title", subtitle = "Subtitle", x = "X-axis", y = "Y-axis") +
  theme(plot.title = element_text(size = 20),
        plot.subtitle = element_text(size = 15),
        axis.title.x = element_text(size = 15),
        axis.title.y = element_text(size = 15),
        axis.text.x = element_text(size = 10),
        axis.text.y = element_text(size = 10))
</pre>
=== Default font ===
* [https://stat.ethz.ch/R-manual/R-devel/library/grDevices/html/png.html ?png].  The default font family is '''Arial''' on Windows and '''Helvetica''' otherwise.
* ''sans''. See [https://www.r-bloggers.com/2015/08/changing-the-font-of-r-base-graphic-plots/ Changing the font of R base graphic plots]
* [http://www.cookbook-r.com/Graphs/Fonts/ Fonts] from ''Cookbook for R''. It seems ggplot2 also uses '''sans''' as the default font.
* [https://www.r-bloggers.com/2021/07/using-different-fonts-with-ggplot2/ Using different fonts with ggplot2]
* [https://r-coder.com/plot-r/#Font_family R plot font family]
* [https://r-coder.com/custom-fonts-r/ Add custom fonts in R]
=== layout ===
* [https://blog.rsquaredacademy.com/data-visualization-with-r-combining-plots/ Data Visualization with R - Combining Plots]
* http://datascienceplus.com/adding-text-to-r-plot/
=== reset the settings ===
{{Pre}}
op <- par(mfrow=c(2,1), mar = c(5,7,4,2) + 0.1)
....
par(op) # mfrow=c(1,1), mar = c(5,4,4,2) + .1
</pre>
=== mtext (margin text) vs title ===
* https://datascienceplus.com/adding-text-to-r-plot/
* https://datascienceplus.com/mastering-r-plot-part-2-axis/
=== mgp (axis tick label locations or axis title) ===
# The margin line (in ‘mex’ units) for the axis title, axis labels and axis line.  Note that ‘mgp[1]’ affects the axis ‘title’ whereas ‘mgp[2:3]’ affect tick mark labels.  The default is ‘c(3, 1, 0)’. If we like to make the axis labels closer to an axis, we can use mgp=c(1.5, .5, 0) for example.
#* the default is c(3,1,0) which specify the margin line for the '''axis title''', '''axis labels''' and '''axis line'''.
#* the axis title is drawn in the fourth line of the margin starting from the plot region, the axis labels are drawn in the second line and the axis line itself is the first line.
# [https://www.r-bloggers.com/2010/06/setting-graph-margins-in-r-using-the-par-function-and-lots-of-cow-milk/ Setting graph margins in R using the par() function and lots of cow milk]
# [https://statisticsglobe.com/move-axis-label-closer-to-plot-in-base-r Move Axis Label Closer to Plot in Base R (2 Examples)]
# http://rfunction.com/archives/1302 mgp – A numeric vector of length 3, which sets the axis label locations relative to the edge of the inner plot window. The first value represents the location the '''labels/axis title''' (i.e. xlab and ylab in plot), the second the '''tick-mark labels''', and third the '''tick marks'''. The default is c(3, 1, 0).
=== move axis title closer to axis ===
* [https://r-charts.com/base-r/title/ Setting a title and a subtitle]. Default is around 1.7(?). [https://www.rdocumentation.org/packages/graphics/versions/3.6.2/topics/title ?title].
* [https://stackoverflow.com/a/30265996 move axis label closer to axis] '''title(, line)'''. This is useful when we use '''xaxt='n' ''' to hide the ticks and labels.
<pre>
title(ylab="Within-cluster variance", line=0,
      cex.lab=1.2, family="Calibri Light")
</pre>
=== pch and point shapes ===
[[:File:R pch.png]]
See [https://www.statmethods.net/advgraphs/parameters.html here].
* Full circle: pch=16
* Display all possibilities: ggpubr::show_point_shapes()
=== lty (line type) ===
[[:File:R lty.png]]
[https://finnstats.com/index.php/2021/06/11/line-types-in-r-lty-for-r-baseplot-and-ggplot/ Line types in R: Ultimate Guide For R Baseplot and ggplot]
See [http://www.sthda.com/english/wiki/line-types-in-r-lty here].
ggpubr::show_line_types()
=== las (label style) ===
0: The default, parallel to the axis
1: Always horizontal <syntaxhighlight lang='r' inline>boxplot(y~x, las=1)</syntaxhighlight>
2: Perpendicular to the axis
3: Always vertical
=== oma (outer margin), xpd, common title for two plots, 3 types of regions, multi-panel plots ===
<ul>
<li>The following trick is useful when we want to draw multiple plots with a common title.
{{Pre}}
par(mfrow=c(1,2),oma = c(0, 0, 2, 0))  # oma=c(0, 0, 0, 0) by default
plot(1:10,  main="Plot 1")
plot(1:100,  main="Plot 2")
mtext("Title for Two Plots", outer = TRUE, cex = 1.5) # outer=FALSE by default
</pre>
<li>[[PCA#Visualization|PCA plot]] example (the plot in the middle)
<li>For scatterplot3d() function, '''oma''' is not useful and I need to use '''xpd'''.
<li>[https://datascienceplus.com/mastering-r-plot-part-3-outer-margins/ Mastering R plot – Part 3: Outer margins] '''mtext()''' & '''par(xpd)'''.
<li>[https://www.rdocumentation.org/packages/graphics/versions/3.6.2/topics/par ?par] about '''xpd''' option
* If FALSE (default), all plotting is clipped to the plot region,
* If TRUE, all plotting is clipped to the figure region,
* If NA, all plotting is clipped to the device region.
<li>3 types of regions. See [https://www.benjaminbell.co.uk/2018/02/creating-multi-panel-plots-and-figures.html Creating multi-panel plots and figures using layout()] & [https://www.seehuhn.de/blog/122 publication-quality figures with R, part 2]
* plot region,
* figure region,
* device region.
<li>[https://www.benjaminbell.co.uk/2018/02/creating-multi-panel-plots-and-figures.html Creating multi-panel plots and figures using layout()] includes several tricks including creating a picture-in-picture plot.
</ul>
=== no.readonly ===
[https://www.zhihu.com/question/54116933 R语言里par(no.readonly=TURE)括号里面这个参数什么意思?], [https://www.jianshu.com/p/a716db5d30ef R-par()]
== Non-standard fonts in postscript and pdf graphics ==
https://cran.r-project.org/doc/Rnews/Rnews_2006-2.pdf#page=41
== NULL, NA, NaN, Inf ==
https://tomaztsql.wordpress.com/2018/07/04/r-null-values-null-na-nan-inf/
== save()/load() vs saveRDS()/readRDS() vs dput()/dget() vs dump()/source() ==
# saveRDS() can only save one R object while save() does not have this constraint.
# saveRDS() doesn’t save the both the object and its name it just saves a representation of the object. As a result, the saved object can be loaded into a named object within R that is different from the name it had when originally serialized. See [http://www.fromthebottomoftheheap.net/2012/04/01/saving-and-loading-r-objects/ this post].
<pre>
x <- 5
saveRDS(x, "myfile.rds")
x2 <- readRDS("myfile.rds")
identical(mod, mod2, ignore.environment = TRUE)
</pre>
[https://www.rdocumentation.org/packages/base/versions/3.6.1/topics/dput dput]: Writes an ASCII text representation of an R object. The object name is not written (unlike '''dump''').
{{Pre}}
$ data(pbc, package = "survival")
$ names(pbc)
$ dput(names(pbc))
c("id", "time", "status", "trt", "age", "sex", "ascites", "hepato",
"spiders", "edema", "bili", "chol", "albumin", "copper", "alk.phos",
"ast", "trig", "platelet", "protime", "stage")
> iris2 <- iris[1:2, ]
> dput(iris2)
structure(list(Sepal.Length = c(5.1, 4.9), Sepal.Width = c(3.5,
3), Petal.Length = c(1.4, 1.4), Petal.Width = c(0.2, 0.2), Species = structure(c(1L,
1L), .Label = c("setosa", "versicolor", "virginica"), class = "factor")), row.names = 1:2, class = "data.frame")
</pre>
=== User 'verbose = TRUE' in load() ===
When we use load(), it is helpful to add 'verbose =TRUE' to see what objects get loaded.
=== What are RDS files anyways ===
[https://www.statworx.com/de/blog/archive-existing-rds-files/ Archive Existing RDS Files]
== [https://www.rdocumentation.org/packages/base/versions/3.5.0/topics/all.equal ==, all.equal(), identical()] ==
* ==: exact match
* '''all.equal''': compare R objects x and y testing ‘near equality’
* identical: The safe and reliable way to test two objects for being exactly equal.
{{Pre}}
x <- 1.0; y <- 0.99999999999
x <- 1.0; y <- 0.99999999999
all.equal(x, y)
all.equal(x, y)
# [1] TRUE
# [1] TRUE
identical(x, y)
identical(x, y)
# [1] FALSE
# [1] FALSE
</pre>
</pre>
 
 
See also the [http://cran.r-project.org/web/packages/testthat/index.html testhat] package.
Be careful about using "==" to return an index of matches in the case of data with missing values.
 
<pre>
=== Numerical Pitfall ===
R> c(1,2,NA)[c(1,2,NA) == 1]
[http://bayesfactor.blogspot.com/2016/05/numerical-pitfalls-in-computing-variance.html Numerical pitfalls in computing variance]
[1]  1 NA
<syntaxhighlight lang='bash'>
R> c(1,2,NA)[which(c(1,2,NA) == 1)]
.1 - .3/3
[1] 1
## [1] 0.00000000000000001388
</pre>
</syntaxhighlight>
 
See also the [http://cran.r-project.org/web/packages/testthat/index.html testhat] package.
 
I found a case when I compare two objects where 1 is generated in ''Linux'' and the other is generated in ''macOS'' that identical() gives FALSE but '''all.equal()''' returns TRUE. The difference has a magnitude only e-17.
 
=== waldo ===
* https://waldo.r-lib.org/ or [https://cloud.r-project.org/web/packages/waldo/index.html CRAN]. Find and concisely describe the difference between a pair of R objects.
* [https://predictivehacks.com/how-to-compare-objects-in-r/ How To Compare Objects In R]
 
=== diffobj: Compare/Diff R Objects ===
https://cran.r-project.org/web/packages/diffobj/index.html
 
== testthat ==
* https://github.com/r-lib/testthat
* [http://www.win-vector.com/blog/2019/03/unit-tests-in-r/ Unit Tests in R]
* [https://davidlindelof.com/machine-learning-in-r-start-with-an-end-to-end-test/ Start with an End-to-End Test]
* [https://www.r-bloggers.com/2023/12/a-beautiful-mind-writing-testable-r-code/ A Beautiful Mind: Writing Testable R Code]
 
== tinytest ==
[https://cran.r-project.org/web/packages/tinytest/index.html tinytest]: Lightweight but Feature Complete Unit Testing Framework
 
[https://cran.r-project.org/web/packages/ttdo/index.html ttdo] adds support of the 'diffobj' package for 'diff'-style comparison of R objects.
 
== Numerical Pitfall ==
[http://bayesfactor.blogspot.com/2016/05/numerical-pitfalls-in-computing-variance.html Numerical pitfalls in computing variance]
{{Pre}}
.1 - .3/3
## [1] 0.00000000000000001388
</pre>
 
== Sys.getpid() ==
This can be used to monitor R process memory usage or stop the R process. See [https://stat.ethz.ch/pipermail/r-devel/2016-November/073360.html this post].
 
== Sys.getenv() & make the script more portable ==
Replace all the secrets from the script and replace them with '''Sys.getenv("secretname")'''. You can save the secrets in an '''.Renviron''' file next to the script in the same project.
<pre>
$ for v in 1 2; do MY=$v Rscript -e "Sys.getenv('MY')"; done
[1] "1"
[1] "2"
$ echo $MY
2
</pre>
 
== How to write R codes ==
* [https://youtu.be/7oyiPBjLAWY Code smells and feels] from R Consortium
** write simple conditions,
** handle class properly,
** return and exit early,
** polymorphism,
** switch() [e.g., switch(var, value1=out1, value2=out2, value3=out3). Several examples in [https://github.com/cran/glmnet/blob/master/R/assess.glmnet.R#L103 glmnet] ]
** case_when(),
** %||%.
* [https://appsilon.com/write-clean-r-code/ 5 Tips for Writing Clean R Code] – Leave Your Code Reviewer Commentless
** Comments
** Strings
** Loops
** Code Sharing
**Good Programming Practices
 
== How to debug an R code ==
[[Debug#R|Debug R]]
 
== Locale bug (grep did not handle UTF-8 properly PR#16264) ==
https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=16264
 
== Path length in dir.create() (PR#17206) ==
https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=17206 (Windows only)
 
== install.package() error, R_LIBS_USER is empty in R 3.4.1 & .libPaths() ==
* https://support.rstudio.com/hc/en-us/community/posts/115008369408-Since-update-to-R-3-4-1-R-LIBS-USER-is-empty and http://r.789695.n4.nabble.com/R-LIBS-USER-on-Ubuntu-16-04-td4740935.html. Modify '''/etc/R/Renviron''' (if you have a sudo right) by uncomment out line 43.
<pre>
R_LIBS_USER=${R_LIBS_USER-'~/R/x86_64-pc-linux-gnu-library/3.4'}
</pre>
* https://stackoverflow.com/questions/44873972/default-r-personal-library-location-is-null. Modify '''$HOME/.Renviron''' by adding a line
<pre>
R_LIBS_USER="${HOME}/R/${R_PLATFORM}-library/3.4"
</pre>
* http://stat.ethz.ch/R-manual/R-devel/library/base/html/libPaths.html. Play with .libPaths()
 
On Mac & R 3.4.0 (it's fine)
{{Pre}}
> Sys.getenv("R_LIBS_USER")
[1] "~/Library/R/3.4/library"
> .libPaths()
[1] "/Library/Frameworks/R.framework/Versions/3.4/Resources/library"
</pre>
 
On Linux & R 3.3.1 (ARM)
{{Pre}}
> Sys.getenv("R_LIBS_USER")
[1] "~/R/armv7l-unknown-linux-gnueabihf-library/3.3"
> .libPaths()
[1] "/home/$USER/R/armv7l-unknown-linux-gnueabihf-library/3.3"
[2] "/usr/local/lib/R/library"
</pre>
 
On Linux & R 3.4.1 (*Problematic*)
{{Pre}}
> Sys.getenv("R_LIBS_USER")
[1] ""
> .libPaths()
[1] "/usr/local/lib/R/site-library" "/usr/lib/R/site-library"
[3] "/usr/lib/R/library"
</pre>
 
I need to specify the '''lib''' parameter when I use the '''install.packages''' command.
{{Pre}}
> install.packages("devtools", "~/R/x86_64-pc-linux-gnu-library/3.4")
> library(devtools)
Error in library(devtools) : there is no package called 'devtools'
 
# Specify lib.loc parameter will not help with the dependency package
> library(devtools, lib.loc = "~/R/x86_64-pc-linux-gnu-library/3.4")
Error: package or namespace load failed for 'devtools':
.onLoad failed in loadNamespace() for 'devtools', details:
  call: loadNamespace(name)
  error: there is no package called 'withr'
 
# A solution is to redefine .libPaths
> .libPaths(c("~/R/x86_64-pc-linux-gnu-library/3.4", .libPaths()))
> library(devtools) # Works
</pre>
 
A better solution is to specify R_LIBS_USER in '''~/.Renviron''' file or '''~/.bash_profile'''; see [http://stat.ethz.ch/R-manual/R-patched/library/base/html/Startup.html ?Startup].
 
== Using external data from within another package ==
https://logfc.wordpress.com/2017/03/02/using-external-data-from-within-another-package/
 
== How to run R scripts from the command line ==
https://support.rstudio.com/hc/en-us/articles/218012917-How-to-run-R-scripts-from-the-command-line
 
== How to exit a sourced R script ==
* [http://stackoverflow.com/questions/25313406/how-to-exit-a-sourced-r-script How to exit a sourced R script]
* [http://r.789695.n4.nabble.com/Problem-using-the-source-function-within-R-functions-td907180.html Problem using the source-function within R-functions] ''' ''The best way to handle the generic sort of problem you are describing is to take those source'd files, and rewrite their content as functions to be called from your other functions.'' '''
* ‘source()’ and ‘example()’ have a new optional argument ‘catch.aborts’ which allows continued evaluation of the R code after an error. [https://developer.r-project.org/blosxom.cgi/R-devel/2023/10/11 4-devel] 2023/10/11.
 
== Decimal point & decimal comma ==
Countries using Arabic numerals with decimal comma (Austria, Belgium, Brazil France, Germany, Netherlands, Norway, South Africa, Spain, Sweden, ...) https://en.wikipedia.org/wiki/Decimal_mark
 
== setting seed locally (not globally) in R ==
https://stackoverflow.com/questions/14324096/setting-seed-locally-not-globally-in-r
 
== R's internal C API ==
https://github.com/hadley/r-internals
 
== cleancall package for C resource cleanup ==
[https://www.tidyverse.org/articles/2019/05/resource-cleanup-in-c-and-the-r-api/ Resource Cleanup in C and the R API]
 
== Random number generator ==
* https://cran.r-project.org/doc/manuals/R-exts.html#Random-numbers
* [https://stackoverflow.com/a/14555220 C code from R with .C(): random value is the same every time]
* [https://arxiv.org/pdf/2003.08009v2.pdf Random number generators produce collisions: Why, how many and more] Marius Hofert 2020 and the published paper in [https://www.tandfonline.com/doi/full/10.1080/00031305.2020.1782261 American Statistician] (including R code).
* R package examples. [https://github.com/cran/party/blob/5ddbd382f01fef2ab993401b43d1fc78d0b061fb/src/RandomForest.c party] package.
 
{{Pre}}
#include <R.h>
 
void myunif(){
  GetRNGstate();
  double u = unif_rand();
  PutRNGstate();
  Rprintf("%f\n",u);
}
</pre>
 
<pre>
$ R CMD SHLIB r_rand.c
$ R
R> dyn.load("r_rand.so")
R> set.seed(1)
R> .C("myunif")
0.265509
list()
R> .C("myunif")
0.372124
list()
R> set.seed(1)
R> .C("myunif")
0.265509
list()
</pre>
 
=== Test For Randomness ===
* [https://predictivehacks.com/how-to-test-for-randomness/ How To Test For Randomness]
* [https://www.r-bloggers.com/2021/08/test-for-randomness-in-r-how-to-check-dataset-randomness/ Test For Randomness in R-How to check Dataset Randomness]
 
== Different results in Mac and Linux ==
=== Random numbers: multivariate normal ===
Why [https://www.rdocumentation.org/packages/MASS/versions/7.3-49/topics/mvrnorm MASS::mvrnorm()] gives different result on Mac and Linux/Windows?
 
The reason could be the covariance matrix decomposition - and that may be due to the LAPACK/BLAS libraries. See
* https://stackoverflow.com/questions/11567613/different-random-number-generation-between-os
* https://stats.stackexchange.com/questions/149321/generating-and-working-with-random-vectors-in-r
<ul>
<li>[https://stats.stackexchange.com/questions/61719/cholesky-versus-eigendecomposition-for-drawing-samples-from-a-multivariate-norma Cholesky versus eigendecomposition for drawing samples from a multivariate normal distribution]
 
See [https://gist.github.com/arraytools/0d7f0a02c233aefb9cefc6eb5f7b7754 this example]. A little more investigation shows the eigen values differ a little bit on macOS and Linux. See [https://gist.github.com/arraytools/0d7f0a02c233aefb9cefc6eb5f7b7754#file-mvtnorm_debug-r here].
</li>
</ul>
 
== rle() running length encoding ==
* https://en.wikipedia.org/wiki/Run-length_encoding
* [https://masterr.org/r/how-to-find-consecutive-repeats-in-r/ How to Find Consecutive Repeats in R]
* [https://www.r-bloggers.com/r-function-of-the-day-rle-2/amp/ R Function of the Day: rle]
* [https://blogs.reed.edu/ed-tech/2015/10/creating-nice-tables-using-r-markdown/ Creating nice tables using R Markdown]
* https://rosettacode.org/wiki/Run-length_encoding
* R's [https://www.rdocumentation.org/packages/base/versions/3.5.2/topics/rle base::rle()] function
* R's [https://www.rdocumentation.org/packages/S4Vectors/versions/0.10.2/topics/Rle-class Rle class] from S4Vectors package which was used in for example [http://genomicsclass.github.io/book/pages/iranges_granges.html IRanges/GRanges/GenomicRanges] package
 
== citation() ==
{{Pre}}
citation()
citation("MASS")
toBibtex(citation())
</pre>
[https://www.r-bloggers.com/2024/05/notes-on-citing-r-and-r-packages/ Notes on Citing R and R Packages] with examples.
 
== R not responding request to interrupt stop process ==
[https://stackoverflow.com/a/43172530 R not responding request to interrupt stop process]. ''R is executing (for example) a C / C++ library call that doesn't provide R an opportunity to check for interrupts.'' It seems to match with the case I'm running (''dist()'' function).
 
== Monitor memory usage ==
* x <- rnorm(2^27) will create an object of the size 1GB (2^27*8/2^20=1024 MB).
* Windows: memory.size(max=TRUE)
* Linux
** RStudio: '''htop -p PID''' where PID is the process ID of ''/usr/lib/rstudio/bin/rsession'', not ''/usr/lib/rstudio/bin/rstudio''. This is obtained by running ''x <- rnorm(2*1e8)''. The object size can be obtained through ''print(object.size(x), units = "auto")''. Note that 1e8*8/2^20 = 762.9395.
** R: '''htop -p PID''' where PID is the process ID of ''/usr/lib/R/bin/exec/R''. Alternatively, use '''htop -p `pgrep -f /usr/lib/R/bin/exec/R`'''
** To find the peak memory usage '''grep VmPeak /proc/$PID/status'''
* '''mem_used()''' function from [https://cran.r-project.org/web/packages/pryr/index.html pryr] package. It is not correct or useful if I use it to check the value compared to the memory returned by '''jobload''' in biowulf. So I cannot use it to see the memory used in running mclapply().
* [https://cran.r-project.org/web/packages/peakRAM/index.html peakRAM]: Monitor the Total and Peak RAM Used by an Expression or Function
* [https://www.zxzyl.com/archives/1456/ Error: protect () : protection stack overflow] and [https://www.rdocumentation.org/packages/base/versions/3.6.2/topics/Memory ?Memory]
 
References:
* [https://unix.stackexchange.com/questions/554/how-to-monitor-cpu-memory-usage-of-a-single-process How to monitor CPU/memory usage of a single process?]. ''htop -p $PID'' is recommended. It only shows the percentage of memory usage.
* [https://stackoverflow.com/questions/774556/peak-memory-usage-of-a-linux-unix-process '''Peak''' memory usage of a linux/unix process] ''grep VmPeak /proc/$PID/status'' is recommended.
* [https://serverfault.com/a/264856 How can I see the memory usage of a Linux process?] ''pmap $PID | tail -n 1'' is recommended. It shows the memory usage in absolute value (eg 1722376K).
* [https://stackoverflow.com/a/6457769 How to check the amount of RAM in R] '''memfree <- as.numeric(system("awk '/MemFree/ {print $2}' /proc/meminfo", intern=TRUE)); memfree '''
 
== Monitor Data ==
[https://www.jstatsoft.org/article/view/v098i01?s=09 Monitoring Data in R with the lumberjack Package]
 
== Pushover ==
[https://rud.is/b/2020/01/29/monitoring-website-ssl-tls-certificate-expiration-times-with-r-openssl-pushoverr-and-dt/ Monitoring Website SSL/TLS Certificate Expiration Times with R, {openssl}, {pushoverr}, and {DT}]
 
[https://cran.r-project.org/web/packages/pushoverr/ pushoverr]
 
= Resource =
== Books ==
* [https://forwards.github.io/rdevguide/ R Development Guide] R Contribution Working Group
* [https://rviews.rstudio.com/2021/11/04/bookdown-org/ An R Community Public Library] 2011-11-04
* A list of recommended books http://blog.revolutionanalytics.com/2015/11/r-recommended-reading.html
* [http://statisticalestimation.blogspot.com/2016/11/learning-r-programming-by-reading-books.html Learning R programming by reading books: A book list]
* [http://www.stats.ox.ac.uk/pub/MASS4/ Modern Applied Statistics with S] by William N. Venables and Brian D. Ripley
* [http://dirk.eddelbuettel.com/code/rcpp.html Seamless R and C++ Integration with Rcpp] by Dirk Eddelbuettel
* [http://www.amazon.com/Advanced-Chapman-Hall-CRC-Series/dp/1466586966/ref=pd_sim_b_6?ie=UTF8&refRID=0C98YDK5MRSTRY0ZX1DB Advanced R] by Hadley Wickham 2014
** http://brettklamer.com/diversions/statistical/compile-hadleys-advanced-r-programming-to-a-pdf/ Compile Hadley's Advanced R to a PDF
* [https://b-rodrigues.github.io/fput/ Functional programming and unit testing for data munging with R] by Bruno Rodrigues
* [http://www.amazon.com/Cookbook-OReilly-Cookbooks-Paul-Teetor/dp/0596809158/ref=pd_sim_b_3?ie=UTF8&refRID=0C98YDK5MRSTRY0ZX1DB R Cookbook] by Paul Teetor
* [http://www.amazon.com/Machine-Learning-R-Brett-Lantz/dp/1782162143/ref=pd_sim_b_13?ie=UTF8&refRID=1851BAX3M17CK00VSMA6 Machine Learning with R] by Brett Lantz
* [http://www.amazon.com/Everyone-Advanced-Analytics-Graphics-Addison-Wesley/dp/0321888030/ref=pd_sim_b_3?ie=UTF8&refRID=1851BAX3M17CK00VSMA6 R for Everyone] by [http://www.jaredlander.com/r-for-everyone/ Jared P. Lander]
* [http://www.amazon.com/The-Art-Programming-Statistical-Software/dp/1593273843/ref=pd_sim_b_2?ie=UTF8&refRID=1851BAX3M17CK00VSMA6 The Art of R Programming] by Norman Matloff
* [http://www.amazon.com/Applied-Predictive-Modeling-Max-Kuhn/dp/1461468485/ref=pd_sim_b_3?ie=UTF8&refRID=0H3NMWX7KTRAEB32902Q Applied Predictive Modeling] by Max Kuhn
* [http://www.amazon.com/R-Action-Robert-Kabacoff/dp/1935182390/ref=pd_sim_b_17?ie=UTF8&refRID=0H3NMWX7KTRAEB32902Q R in Action] by Robert Kabacoff
* [http://www.amazon.com/The-Book-Michael-J-Crawley/dp/0470973927/ref=pd_sim_b_6?ie=UTF8&refRID=0CNF2XK8VBGF5A6W3NE3 The R Book] by Michael J. Crawley
* Regression Modeling Strategies, with Applications to Linear Models, Survival Analysis and Logistic Regression by Frank E. Harrell
* Data Manipulation with R by Phil Spector
* [https://www.datanovia.com/en/courses/data-manipulation-in-r/ DATA MANIPULATION IN R] by ALBOUKADEL KASSAMBARA
* [https://rviews.rstudio.com/2017/05/19/efficient_r_programming/ Review of Efficient R Programming]
* [http://r-pkgs.had.co.nz/ R packages: Organize, Test, Document, and Share Your Code] by Hadley Wicklam 2015
* [http://tidytextmining.com/ Text Mining with R: A Tidy Approach] and a [http://pacha.hk/2017-05-20_text_mining_with_r.html blog]
<ul>
<li>[https://github.com/csgillespie/efficientR Efficient R programming] by Colin Gillespie and Robin Lovelace. It works to re-create the html version of the book if we follow their simple instruction in the [https://csgillespie.github.io/efficientR/building-the-book-from-source.html Appendix]. Note that pdf version has advantages of expected output (mathematical notations, tables) over the epub version.
{{Pre}}
# R 3.4.1
.libPaths(c("~/R/x86_64-pc-linux-gnu-library/3.4", .libPaths()))
setwd("/tmp/efficientR/")
bookdown::render_book("index.Rmd", output_format = "bookdown::pdf_book")
# generated pdf file is located _book/_main.pdf
 
bookdown::render_book("index.Rmd", output_format = "bookdown::epub_book")
# generated epub file is located _book/_main.epub.
# This cannot be done in RStudio ("parse_dt" not resolved from current namespace (lubridate))
# but it is OK to run in an R terminal
</pre>
</li>
</ul>
* [https://learningstatisticswithr.com/book/ Learning statistics with R: A tutorial for psychology students and other beginners] by Danielle Navarro
* [https://rstats.wtf/ What They Forgot to Teach You About R] Jennifer Bryan & Jim Hester
* [http://knosof.co.uk/ESEUR/ Evidence-based Software Engineering] by Derek M. Jones
* [https://www.bigbookofr.com/index.html Big Book of R]
* [https://epirhandbook.com/?s=09 R for applied epidemiology and public health]
* [http://bendixcarstensen.com/EwR/ Epidemiology with R] and the [https://cran.r-project.org/web/packages/Epi/ Epi] package. [https://rdrr.io/cran/Epi/man/ci.lin.html ci.lin()] function to return the CI from glm() fit.
* [https://education.rstudio.com/learn/ RStudio &rarr; Finding Your Way To R]. Beginners/Intermediates/Experts
* [https://deepr.gagolewski.com/index.html Deep R Programming]
 
== Videos ==
* [https://www.infoworld.com/article/3411819/do-more-with-r-video-tutorials.html “Do More with R” video tutorials]. Search for R video tutorials by task, topic, or package. Most videos are shorter than 10 minutes.
* [https://www.youtube.com/@RLadiesGlobal/videos R-Ladies Global] (youtube)
 
=== Webinar ===
* [https://www.rstudio.com/resources/webinars/ RStudio] & its [https://github.com/rstudio/webinars github] repository
 
== useR! ==
* http://blog.revolutionanalytics.com/2017/07/revisiting-user2017.html
* [https://www.youtube.com/watch?v=JacpQdj1Vfc&list=PL4IzsxWztPdnyAKQQLxA4ucpaCLdsKvZw UseR 2018 workshop and tutorials]
* [http://www.user2019.fr/ UseR! 2019], [https://github.com/sowla/useR2019-materials tutorial], [https://www.mango-solutions.com/blog/user2019-roundup-workflow-reproducibility-and-friends Better workflow]
* [https://www.youtube.com/channel/UC_R5smHVXRYGhZYDJsnXTwg/playlists UseR! 2020 & 2021]
* [https://rviews.rstudio.com/2021/09/09/a-guide-to-binge-watching-r-medicine/ A Guide to Binge Watching R / Medicine 2021]
* [https://t.co/QBZwNoPJsC UseR! 2022]
 
== R consortium ==
https://www.youtube.com/channel/UC_R5smHVXRYGhZYDJsnXTwg/featured
 
== Blogs, Tips, Socials, Communities ==
* Google: revolutionanalytics In case you missed it
* [http://r4stats.com/articles/why-r-is-hard-to-learn/ Why R is hard to learn] by Bob Musenchen.
* [http://onetipperday.sterding.com/2016/02/my-15-practical-tips-for.html My 15 practical tips for a bioinformatician]
* [http://blog.revolutionanalytics.com/2017/06/r-community.html The R community is one of R's best features]
* [https://hbctraining.github.io/main/ Bioinformatics Training at the Harvard Chan Bioinformatics Core]
* The R Blog <s>https://developer.r-project.org/Blog/public/</s> https://blog.r-project.org/
* [https://www.dataquest.io/blog/top-tips-for-learning-r-from-africa-rs-shelmith-kariuki/ Top Tips for Learning R from Africa R’s Shelmith Kariuki]
* [https://smach.github.io/R4JournalismBook/HowDoI.html How Do I? …(do that in R)] by Sharon Machlis
* [https://www.t4rstats.com/ Twitter for R programmers]
 
== Bug Tracking System ==
https://bugs.r-project.org/bugzilla3/ and [https://bugs.r-project.org/bugzilla3/query.cgi Search existing bug reports]. Remember to select 'All' in the Status drop-down list.


=== How to debug an R code ===
Use '''sessionInfo()'''.
==== Using assign() in functions ====
For example, insert the following line to your function
<pre>
assign(envir=globalenv(), "GlobalVar", localvar)
</pre>


=== Debug R source code ===
== License ==
==== Build R with debug information ====
[http://www.win-vector.com/blog/2019/07/some-notes-on-gnu-licenses-in-r-packages/ Some Notes on GNU Licenses in R Packages]
* [[R#Build_R_from_its_source|R -> Build R from its source on Windows]]
* http://www.stats.uwo.ca/faculty/murdoch/software/debuggingR/
* http://www.stats.uwo.ca/faculty/murdoch/software/debuggingR/gdb.shtml
* [https://github.com/arraytools/r-debug My note of debugging cor() function]


==== .Call ====
[https://moderndata.plot.ly/why-dash-uses-the-mit-license/ Why Dash uses the mit license (and not a copyleft gpl license)]
* [https://cran.rstudio.com/doc/manuals/r-release/R-exts.html#Calling-_002eCall Writing R Extensions] manual.


==== Registering native routines ====
== Interview questions ==
https://cran.rstudio.com/doc/manuals/r-release/R-exts.html#Registering-native-routines
* Does R store matrices in column-major order or row-major order?
** Matrices are stored in column-major order, which means that elements are arranged and accessed by columns. This is in contrast to languages like Python, where matrices (or arrays) are typically stored in row-major order.


Pay attention to the prefix argument '''.fixes''' (eg .fixes = "C_") in '''useDynLib()''' function in the NAMESPACE file.
* Explain the difference between == and === in R. Provide an example to illustrate their use.
 
** The == operator is used for testing equality of values in R. It returns TRUE if the values on the left and right sides are equal, otherwise FALSE. The === operator does not exist in base R.
==== Example of debugging cor() function ====
Note that R's cor() function called a C function cor().
<pre>
stats::cor
....
.Call(C_cor, x, y, na.method, method == "kendall")
</pre>


A step-by-step screenshot of debugging using the GNU debugger '''gdb''' can be found on my Github repository https://github.com/arraytools/r-debug.
* What is the purpose of the apply() function in R? How does it differ from the for loop?
** The apply() function in R is used to apply a function over the margins of an array or matrix. It is often used as an alternative to loops for applying a function to each row or column of a matrix.


=== Locale bug (grep did not handle UTF-8 properly PR#16264) ===
* Describe the concept of factors in R. How are they used in data manipulation and analysis?
https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=16264
** Factors in R are used to represent categorical data. They are an essential data type for statistical modeling and analysis. Factors store both the unique values that occur in a dataset and the corresponding integer codes used to represent those values.


== Resource ==
* What is the significance
=== Books ===
of the attach() and detach() functions in R? When should they be used?
* A list of recommended books http://blog.revolutionanalytics.com/2015/11/r-recommended-reading.html
** A: The attach() function is used to add a data frame to the search path in R, making it easier to access variables within the data frame. The detach() function is used to remove a data frame from the search path, which can help avoid naming conflicts and reduce memory usage.
* [http://www.stats.ox.ac.uk/pub/MASS4/ Modern Applied Statistics with S] by William N. Venables and Brian D. Ripley
* [http://dirk.eddelbuettel.com/code/rcpp.html Seamless R and C++ Integration with Rcpp] by Dirk Eddelbuettel
* [http://www.amazon.com/Advanced-Chapman-Hall-CRC-Series/dp/1466586966/ref=pd_sim_b_6?ie=UTF8&refRID=0C98YDK5MRSTRY0ZX1DB Advanced R] by Hadley Wickham
* [http://www.amazon.com/Cookbook-OReilly-Cookbooks-Paul-Teetor/dp/0596809158/ref=pd_sim_b_3?ie=UTF8&refRID=0C98YDK5MRSTRY0ZX1DB R Cookbook] by Paul Teetor
* [http://www.amazon.com/Machine-Learning-R-Brett-Lantz/dp/1782162143/ref=pd_sim_b_13?ie=UTF8&refRID=1851BAX3M17CK00VSMA6 Machine Learning with R] by Brett Lantz
* [http://www.amazon.com/Everyone-Advanced-Analytics-Graphics-Addison-Wesley/dp/0321888030/ref=pd_sim_b_3?ie=UTF8&refRID=1851BAX3M17CK00VSMA6 R for Everyone] by [http://www.jaredlander.com/r-for-everyone/ Jared P. Lander]
* [http://www.amazon.com/The-Art-Programming-Statistical-Software/dp/1593273843/ref=pd_sim_b_2?ie=UTF8&refRID=1851BAX3M17CK00VSMA6 The Art of R Programming] by Norman Matloff
* [http://www.amazon.com/Applied-Predictive-Modeling-Max-Kuhn/dp/1461468485/ref=pd_sim_b_3?ie=UTF8&refRID=0H3NMWX7KTRAEB32902Q Applied Predictive Modeling] by Max Kuhn
* [http://www.amazon.com/R-Action-Robert-Kabacoff/dp/1935182390/ref=pd_sim_b_17?ie=UTF8&refRID=0H3NMWX7KTRAEB32902Q R in Action] by Robert Kabacoff
* [http://www.amazon.com/The-Book-Michael-J-Crawley/dp/0470973927/ref=pd_sim_b_6?ie=UTF8&refRID=0CNF2XK8VBGF5A6W3NE3 The R Book] by Michael J. Crawley
* Regression Modeling Strategies, with Applications to Linear Models, Survival Analysis and Logistic Regression by Frank E. Harrell
* Data Manipulation with R by Phil Spector


=== Webinar ===
* Explain the concept of vectorization in R. How does it impact the performance of R code?
* [https://www.rstudio.com/resources/webinars/ RStudio] & its [https://github.com/rstudio/webinars github] repository
** Vectorization in R refers to the ability to apply operations to entire vectors or arrays at once, without needing to write explicit loops. This can significantly improve the performance of R code, as it allows operations to be performed in a more efficient, vectorized manner by taking advantage of R's underlying C code.


=== Blogs, Tips ===
* Describe the difference between data.frame and matrix in R. When would you use one over the other?
* [http://r4stats.com/articles/why-r-is-hard-to-learn/ Why R is hard to learn] by Bob Musenchen.
** A data.frame in R is a two-dimensional structure that can store different types of data (e.g., numeric, character, factor) in its columns. It is similar to a table in a database.
* [http://onetipperday.sterding.com/2016/02/my-15-practical-tips-for.html My 15 practical tips for a bioinformatician]
** A matrix in R is also a two-dimensional structure, but it can only store elements of the same data type. It is more like a mathematical matrix.
** You would use a data.frame when you have heterogeneous data (i.e., different types of data) and need to work with it as a dataset. You would use a matrix when you have homogeneous data (i.e., the same type of data) and need to perform matrix operations.


=== Bug Tracking System ===
* What are the benefits of using the dplyr package in R for data manipulation? Provide an example of how you would use dplyr to filter a data frame.
https://bugs.r-project.org/bugzilla3/ and [https://bugs.r-project.org/bugzilla3/query.cgi Search existing bug reports]. Remember to select 'All' in the Status drop-down list.
** The dplyr package provides a set of functions that make it easier to manipulate data frames in R.
** It uses a syntax that is easy to read and understand, making complex data manipulations more intuitive.
** To filter a data frame using dplyr, you can use the filter() function. For example, filter(df, column_name == value) would filter df to include only rows where column_name is equal to value.

Latest revision as of 13:31, 18 October 2024

Install and upgrade R

Here

New release

Online Editor

We can run R on web browsers without installing it on local machines (similar to [/ideone.com Ideone.com] for C++. It does not require an account either (cf RStudio).

rdrr.io

It can produce graphics too. The package I am testing (cobs) is available too.

rstudio.cloud

RDocumentation

The interactive engine is based on DataCamp Light

For example, tbl_df function from dplyr package.

The website DataCamp allows to run library() on the Script window. After that, we can use the packages on R Console.

Here is a list of (common) R packages that users can use on the web.

The packages on RDocumentation may be outdated. For example, the current stringr on CRAN is v1.2.0 (2/18/2017) but RDocumentation has v1.1.0 (8/19/2016).

Web Applications

R web applications

Creating local repository for CRAN and Bioconductor

R repository

Parallel Computing

See R parallel.

Cloud Computing

Install R on Amazon EC2

http://randyzwitch.com/r-amazon-ec2/

Bioconductor on Amazon EC2

http://www.bioconductor.org/help/bioconductor-cloud-ami/

Big Data Analysis

bigmemory, biganalytics, bigtabulate

ff, ffbase

biglm

data.table

See data.table.

disk.frame

Split-apply-combine for Maximum Likelihood Estimation of a linear model

Apache arrow

Reproducible Research

Reproducible Environments

https://rviews.rstudio.com/2019/04/22/reproducible-environments/

checkpoint package

Some lessons in R coding

  1. don't use rand() and srand() in c. The result is platform dependent. My experience is Ubuntu/Debian/CentOS give the same result but they are different from macOS and Windows. Use Rcpp package and R's random number generator instead.
  2. don't use list.files() directly. The result is platform dependent even different Linux OS. An extra sorting helps!

Useful R packages

Rcpp

http://cran.r-project.org/web/packages/Rcpp/index.html. See more here.

RInside : embed R in C++ code

Ubuntu

With RInside, R can be embedded in a graphical application. For example, $HOME/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/qt directory includes source code of a Qt application to show a kernel density plot with various options like kernel functions, bandwidth and an R command text box to generate the random data. See my demo on Youtube. I have tested this qtdensity example successfully using Qt 4.8.5.

  1. Follow the instruction cairoDevice to install required libraries for cairoDevice package and then cairoDevice itself.
  2. Install Qt. Check 'qmake' command becomes available by typing 'whereis qmake' or 'which qmake' in terminal.
  3. Open Qt Creator from Ubuntu start menu/Launcher. Open the project file $HOME/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/qt/qtdensity.pro in Qt Creator.
  4. Under Qt Creator, hit 'Ctrl + R' or the big green triangle button on the lower-left corner to build/run the project. If everything works well, you shall see the interactive program qtdensity appears on your desktop.

File:qtdensity.png

With RInside + Wt web toolkit installed, we can also create a web application. To demonstrate the example in examples/wt directory, we can do

cd ~/R/x86_64-pc-linux-gnu-library/3.0/RInside/examples/wt
make
sudo ./wtdensity --docroot . --http-address localhost --http-port 8080

Then we can go to the browser's address bar and type http://localhost:8080 to see how it works (a screenshot is in here).

Windows 7

To make RInside works on Windows OS, try the following

  1. Make sure R is installed under C:\ instead of C:\Program Files if we don't want to get an error like g++.exe: error: Files/R/R-3.0.1/library/RInside/include: No such file or directory.
  2. Install RTools
  3. Instal RInside package from source (the binary version will give an error )
  4. Create a DOS batch file containing necessary paths in PATH environment variable
@echo off
set PATH=C:\Rtools\bin;c:\Rtools\gcc-4.6.3\bin;%PATH%
set PATH=C:\R\R-3.0.1\bin\i386;%PATH%
set PKG_LIBS=`Rscript -e "Rcpp:::LdFlags()"`
set PKG_CPPFLAGS=`Rscript -e "Rcpp:::CxxFlags()"`
set R_HOME=C:\R\R-3.0.1
echo Setting environment for using R
cmd

In the Windows command prompt, run

cd C:\R\R-3.0.1\library\RInside\examples\standard
make -f Makefile.win

Now we can test by running any of executable files that make generates. For example, rinside_sample0.

rinside_sample0

As for the Qt application qdensity program, we need to make sure the same version of MinGW was used in building RInside/Rcpp and Qt. See some discussions in

So the Qt and Wt web tool applications on Windows may or may not be possible.

GUI

Qt and R

tkrplot

On Ubuntu, we need to install tk packages, such as by

sudo apt-get install tk-dev

reticulate - Interface to 'Python'

Python -> reticulate

Hadoop (eg ~100 terabytes)

See also HighPerformanceComputing

RHadoop

Snowdoop: an alternative to MapReduce algorithm

XML

On Ubuntu, we need to install libxml2-dev before we can install XML package.

sudo apt-get update
sudo apt-get install libxml2-dev

On CentOS,

yum -y install libxml2 libxml2-devel

XML

library(XML)

# Read and parse HTML file
doc.html = htmlTreeParse('http://apiolaza.net/babel.html', useInternal = TRUE)

# Extract all the paragraphs (HTML tag is p, starting at
# the root of the document). Unlist flattens the list to
# create a character vector.
doc.text = unlist(xpathApply(doc.html, '//p', xmlValue))

# Replace all by spaces
doc.text = gsub('\n', ' ', doc.text)

# Join all the elements of the character vector into a single
# character string, separated by spaces
doc.text = paste(doc.text, collapse = ' ')

This post http://stackoverflow.com/questions/25315381/using-xpathsapply-to-scrape-xml-attributes-in-r can be used to monitor new releases from github.com.

> library(RCurl) # getURL()
> library(XML)   # htmlParse and xpathSApply
> xData <- getURL("https://github.com/alexdobin/STAR/releases")
> doc = htmlParse(xData)
> plain.text <- xpathSApply(doc, "//span[@class='css-truncate-target']", xmlValue)
  # I look at the source code and search 2.5.3a and find the tag as
  # 2.5.3a
> plain.text
 [1] "2.5.3a"      "2.5.2b"      "2.5.2a"      "2.5.1b"      "2.5.1a"     
 [6] "2.5.0c"      "2.5.0b"      "STAR_2.5.0a" "STAR_2.4.2a" "STAR_2.4.1d"
>
> # try bwa
> > xData <- getURL("https://github.com/lh3/bwa/releases")
> doc = htmlParse(xData)
> xpathSApply(doc, "//span[@class='css-truncate-target']", xmlValue)
[1] "v0.7.15" "v0.7.13"

> # try picard
> xData <- getURL("https://github.com/broadinstitute/picard/releases")
> doc = htmlParse(xData)
> xpathSApply(doc, "//span[@class='css-truncate-target']", xmlValue)
 [1] "2.9.1" "2.9.0" "2.8.3" "2.8.2" "2.8.1" "2.8.0" "2.7.2" "2.7.1" "2.7.0"
[10] "2.6.0"

This method can be used to monitor new tags/releases from some projects like Cura, BWA, Picard, STAR. But for some projects like sratools the class attribute in the span element ("css-truncate-target") can be different (such as "tag-name").

xmlview

RCurl

On Ubuntu, we need to install the packages (the first one is for XML package that RCurl suggests)

# Test on Ubuntu 14.04
sudo apt-get install libxml2-dev
sudo apt-get install libcurl4-openssl-dev

Scrape google scholar results

https://github.com/tonybreyal/Blog-Reference-Functions/blob/master/R/googleScholarXScraper/googleScholarXScraper.R

No google ID is required

Seems not work

 Error in data.frame(footer = xpathLVApply(doc, xpath.base, "/font/span[@class='gs_fl']",  : 
  arguments imply differing number of rows: 2, 0 

devtools

devtools package depends on Curl. It actually depends on some system files. If we just need to install a package, consider the remotes package which was suggested by the BiocManager package.

# Ubuntu 14.04
sudo apt-get install libcurl4-openssl-dev

# Ubuntu 16.04, 18.04
sudo apt-get install build-essential libcurl4-gnutls-dev libxml2-dev libssl-dev

# Ubuntu 20.04
sudo apt-get install -y libxml2-dev libcurl4-openssl-dev libssl-dev

Lazy-load database XXX is corrupt. internal error -3. It often happens when you use install_github to install a package that's currently loaded; try restarting R and running the app again.

NB. According to the output of apt-cache show r-cran-devtools, the binary package is very old though apt-cache show r-base and supported packages like survival shows the latest version.

httr

httr imports curl, jsonlite, mime, openssl and R6 packages.

When I tried to install httr package, I got an error and some message:

Configuration failed because openssl was not found. Try installing:
 * deb: libssl-dev (Debian, Ubuntu, etc)
 * rpm: openssl-devel (Fedora, CentOS, RHEL)
 * csw: libssl_dev (Solaris)
 * brew: openssl (Mac OSX)
If openssl is already installed, check that 'pkg-config' is in your
PATH and PKG_CONFIG_PATH contains a openssl.pc file. If pkg-config
is unavailable you can set INCLUDE_DIR and LIB_DIR manually via:
R CMD INSTALL --configure-vars='INCLUDE_DIR=... LIB_DIR=...'
--------------------------------------------------------------------
ERROR: configuration failed for package ‘openssl’

It turns out after I run sudo apt-get install libssl-dev in the terminal (Debian), it would go smoothly with installing httr package. Nice httr!

Real example: see this post. Unfortunately I did not get a table result; I only get an html file (R 3.2.5, httr 1.1.0 on Ubuntu and Debian).

Since httr package was used in many other packages, take a look at how others use it. For example, aRxiv package.

A package to download free Springer books during Covid-19 quarantine, An update to "An adventure in downloading books" (rvest package)

curl

curl is independent of RCurl package.

library(curl)
h <- new_handle()
handle_setform(h,
  name="aaa", email="bbb"
)
req <- curl_fetch_memory("http://localhost/d/phpmyql3_scripts/ch02/form2.html", handle = h)
rawToChar(req$content)

rOpenSci packages

rOpenSci contains packages that allow access to data repositories through the R statistical programming environment

remotes

Download and install R packages stored in 'GitHub', 'BitBucket', or plain 'subversion' or 'git' repositories. This package is a lightweight replacement of the 'install_*' functions in 'devtools'. Also remotes does not require any extra OS level library (at least on Ubuntu 16.04).

Example:

# https://github.com/henrikbengtsson/matrixstats
remotes::install_github('HenrikBengtsson/matrixStats@develop')

DirichletMultinomial

On Ubuntu, we do

sudo apt-get install libgsl0-dev

Create GUI

gWidgets

GenOrd: Generate ordinal and discrete variables with given correlation matrix and marginal distributions

here

json

R web -> json

Map

leaflet

choroplethr

ggplot2

How to make maps with Census data in R

googleVis

See an example from RJSONIO above.

googleAuthR

Create R functions that interact with OAuth2 Google APIs easily, with auto-refresh and Shiny compatibility.

gtrendsR - Google Trends

quantmod

Maintaining a database of price files in R. It consists of 3 steps.

  1. Initial data downloading
  2. Update existing data
  3. Create a batch file

caret

Tool for connecting Excel with R

write.table

Output a named vector

vec <- c(a = 1, b = 2, c = 3)
write.csv(vec, file = "my_file.csv", quote = F)
x = read.csv("my_file.csv", row.names = 1)
vec2 <- x[, 1]
names(vec2) <- rownames(x)
all.equal(vec, vec2)

# one liner: row names of a 'matrix' become the names of a vector
vec3 <- as.matrix(read.csv('my_file.csv', row.names = 1))[, 1]
all.equal(vec, vec3)

Avoid leading empty column to header

write.table writes unwanted leading empty column to header when has rownames

write.table(a, 'a.txt', col.names=NA)
# Or better by
write.table(data.frame("SeqId"=rownames(a), a), "a.txt", row.names=FALSE)

Add blank field AND column names in write.table

  • write.table(, row.names = TRUE) will miss one element on the 1st row when "row.names = TRUE" which is enabled by default.
    • Suppose x is (n x 2)
    • write.table(x, sep="\t") will generate a file with 2 element on the 1st row
    • read.table(file) will return an object with a size (n x 2)
    • read.delim(file) and read.delim2(file) will also be correct
  • Note that write.csv() does not have this issue that write.table() has
    • Suppose x is (n x 2)
    • Suppose we use write.csv(x, file). The csv file will be ((n+1) x 3) b/c the header row.
    • If we use read.csv(file), the object is (n x 3). So we need to use read.csv(file, row.names = 1)
  • adding blank field AND column names in write.table(); write.table writes unwanted leading empty column to header when has rownames
write.table(a, 'a.txt', col.names=NA)
  • readr::write_tsv() does not include row names in the output file

read.delim(, row.names=1) and write.table(, row.names=TRUE)

How to Use read.delim Function in R

Case 1: no row.names

write.table(df, 'my_data.txt', quote=FALSE, sep='\t', row.names=FALSE)
my_df <- read.delim('my_data.txt')  # the rownames will be 1, 2, 3, ...

Case 2: with row.names. Note: if we open the text file in Excel, we'll see the 1st row is missing one header at the end. It is actually missing the column name for the 1st column.

write.table(df, 'my_data.txt', quote=FALSE, sep='\t', row.names=TRUE)
my_df <- read.delim('my_data.txt')  # it will automatically assign the rownames

Read/Write Excel files package

  • http://www.milanor.net/blog/?p=779
  • flipAPI. One useful feature of DownloadXLSX, which is not supported by the readxl package, is that it can read Excel files directly from the URL.
  • xlsx: depends on Java
  • openxlsx: not depend on Java. Depend on zip application. On Windows, it seems to be OK without installing Rtools. But it can not read xls file; it works on xlsx file.
  • readxl: it does not depend on anything although it can only read but not write Excel files.
    • It is part of tidyverse package. The readxl website provides several articles for more examples.
    • readxl webinar.
    • One advantage of read_excel (as with read_csv in the readr package) is that the data imports into an easy to print object with three attributes a tbl_df, a tbl and a data.frame.
    • For writing to Excel formats, use writexl or openxlsx package.
library(readxl)
read_excel(path, sheet = NULL, range = NULL, col_names = TRUE, 
    col_types = NULL, na = "", trim_ws = TRUE, skip = 0, n_max = Inf, 
    guess_max = min(1000, n_max), progress = readxl_progress(), 
    .name_repair = "unique")
# Example
read_excel(path, range = cell_cols("c:cx"), col_types = "numeric")
  • writexl: zero dependency xlsx writer for R
library(writexl)
mylst <- list(sheet1name = df1, sheet2name = df2)
write_xlsx(mylst, "output.xlsx")

For the Chromosome column, integer values becomes strings (but converted to double, so 5 becomes 5.000000) or NA (empty on sheets).

> head(read_excel("~/Downloads/BRCA.xls", 4)[ , -9], 3)
  UniqueID (Double-click) CloneID UGCluster
1                   HK1A1   21652 Hs.445981
2                   HK1A2   22012 Hs.119177
3                   HK1A4   22293 Hs.501376
                                                    Name Symbol EntrezID
1 Catenin (cadherin-associated protein), alpha 1, 102kDa CTNNA1     1495
2                              ADP-ribosylation factor 3   ARF3      377
3                          Uroporphyrinogen III synthase   UROS     7390
  Chromosome      Cytoband ChimericClusterIDs Filter
1   5.000000        5q31.2               <NA>      1
2  12.000000         12q13               <NA>      1
3       <NA> 10q25.2-q26.3               <NA>      1

The hidden worksheets become visible (Not sure what are those first rows mean in the output).

> excel_sheets("~/Downloads/BRCA.xls")
DEFINEDNAME: 21 00 00 01 0b 00 00 00 02 00 00 00 00 00 00 0d 3b 01 00 00 00 9a 0c 00 00 1a 00 
DEFINEDNAME: 21 00 00 01 0b 00 00 00 04 00 00 00 00 00 00 0d 3b 03 00 00 00 9b 0c 00 00 0a 00 
DEFINEDNAME: 21 00 00 01 0b 00 00 00 03 00 00 00 00 00 00 0d 3b 02 00 00 00 9a 0c 00 00 06 00 
[1] "Experiment descriptors" "Filtered log ratio"     "Gene identifiers"      
[4] "Gene annotations"       "CollateInfo"            "GeneSubsets"           
[7] "GeneSubsetsTemp"       

The Chinese character works too.

> read_excel("~/Downloads/testChinese.xlsx", 1)
   中文 B C
1     a b c
2     1 2 3

To read all worksheets we need a convenient function

read_excel_allsheets <- function(filename) {
    sheets <- readxl::excel_sheets(filename)
    sheets <- sheets[-1] # Skip sheet 1
    x <- lapply(sheets, function(X) readxl::read_excel(filename, sheet = X, col_types = "numeric"))
    names(x) <- sheets
    x
}
dcfile <- "table0.77_dC_biospear.xlsx"
dc <- read_excel_allsheets(dcfile)
# Each component (eg dc1) is a tibble.

readr

Compared to base equivalents like read.csv(), readr is much faster and gives more convenient output: it never converts strings to factors, can parse date/times, and it doesn’t munge the column names.

1.0.0 released. readr 2.0.0 adds built-in support for reading multiple files at once, fast multi-threaded lazy reading and automatic guessing of delimiters among other changes.

Consider a text file where the table (6100 x 22) has duplicated row names and the (1,1) element is empty. The column names are all unique.

  • read.delim() will treat the first column as rownames but it does not allow duplicated row names. Even we use row.names=NULL, it still does not read correctly. It does give warnings (EOF within quoted string & number of items read is not a multiple of the number of columns). The dim is 5177 x 22.
  • readr::read_delim(Filename, "\t") will miss the last column. The dim is 6100 x 21.
  • data.table::fread(Filename, sep = "\t") will detect the number of column names is less than the number of columns. Added 1 extra default column name for the first column which is guessed to be row names or an index. The dim is 6100 x 22. (Winner!)

The readr::read_csv() function is as fast as data.table::fread() function. For files beyond 100MB in size fread() and read_csv() can be expected to be around 5 times faster than read.csv(). See 5.3 of Efficient R Programming book.

Note that data.table::fread() can read a selection of the columns.

Speed comparison

The Fastest Way To Read And Write Files In R. data.table >> readr >> base.

ggplot2

See ggplot2

Data Manipulation & Tidyverse

See Tidyverse.

Data Science

See Data science page

microbenchmark & rbenchmark

Plot, image

jpeg

If we want to create the image on this wiki left hand side panel, we can use the jpeg package to read an existing plot and then edit and save it.

We can also use the jpeg package to import and manipulate a jpg image. See Fun with Heatmaps and Plotly.

EPS/postscript format

  • Don't use postscript().
  • Use cairo_ps(). See aving High-Resolution ggplots: How to Preserve Semi-Transparency. It works on base R plots too.
    cairo_ps(filename = "survival-curves.eps",
             width = 7, height = 7, pointsize = 12,
             fallback_resolution = 300)
    print(p) # or any base R plots statements
    dev.off()
  • Export a graph to .eps file with R.
    • The results looks the same as using cairo_ps().
    • The file size by setEPS() + postscript() is quite smaller compared to using cairo_ps().
    • However, grep can find the characters shown on the plot generated by cairo_ps() but not setEPS() + postscript().
    setEPS()
    postscript("whatever.eps") # 483 KB
    plot(rnorm(20000))
    dev.off()
    # grep rnorm whatever.eps # Not found!
    
    cairo_ps("whatever_cairo.eps")   # 2.4 MB
    plot(rnorm(20000))
    dev.off()
    # grep rnorm whatever_cairo.eps  # Found!
    
  • View EPS files
    • Linux: evince. It is installed by default.
    • Mac: evince. brew install evince
    • Windows. Install ghostscript 9.20 (10.x does not work with ghostview/GSview) and ghostview/GSview (5.0). In Ghostview, open Options -> Advanced Configure. Change Ghostscript DLL path AND Ghostscript include Path according to the ghostscript location ("C:\.
  • Edit EPS files: Inkscape
    • Step 1: open the EPS file
    • Step 2: EPS Input: Determine page orientation from text direction 'Page by page' - OK
    • Step 3: PDF Import Settings: default is "Internal import", but we shall choose "Cairo import".
    • Step 4: Zoom in first.
    • Step 5: Click on Layers and Objects tab on the RHS. Now we can select any lines or letters and edit them as we like. The selected objects are highlighted in the "Layers and Objects" panel. That is, we can select multiple objects using object names. The selected objects can be rotated (Object -> Rotate 90 CW), for example.
    • Step 6: We can save the plot as any formats like svg, eps, pdf, html, pdf, ...

png and resolution

It seems people use res=300 as a definition of high resolution.

  • Bottom line: fix res=300 and adjust height/width as needed. The default is res=72, height=width=480. If we increase res=300, the text font size will be increased, lines become thicker and the plot looks like a zoom-in.
  • Saving high resolution plot in png.
    png("heatmap.png", width = 8, height = 6, units='in', res = 300) 
    # we can adjust width/height as we like
    # the pixel values will be width=8*300 and height=6*300 which is equivalent to 
    # 8*300 * 6*300/10^6 = 4.32 Megapixels (1M pixels = 10^6 pixels) in camera's term
    # However, if we use png(, width=8*300, height=6*300, units='px'), it will produce
    # a plot with very large figure body and tiny text font size.
    
    # It seems the following command gives the same result as above
    png("heatmap.png", width = 8*300, height = 6*300, res = 300) # default units="px"
    
  • Chapter 14.5 Outputting to Bitmap (PNG/TIFF) Files by R Graphics Cookbook
    • Changing the resolution affects the size (in pixels) of graphical objects like text, lines, and points.
  • 10 tips for making your R graphics look their best David Smith
    • In Word you can resize the graphic to an appropriate size, but the high resolution gives you the flexibility to choose a size while not compromising on the quality. I'd recommend at least 1200 pixels on the longest side for standard printers.
  • ?png. The png function has default settings ppi=72, height=480, width=480, units="px".
    • By default no resolution is recorded in the file, except for BMP.
    • BMP vs PNG format. If you need a smaller file size and don’t mind a lossless compression, PNG might be a better choice. If you need to retain as much detail as possible and don’t mind a larger file size, BMP could be the way to go.
      • Compression: BMP files are raw and uncompressed, meaning they’re large files that retain as much detail as possible. On the other hand, PNG files are compressed but still lossless. This means you can reduce or expand PNGs without losing any information.
      • File size: BMPs are larger than PNGs. This is because PNG files automatically compress, and can be compressed again to make the file even smaller.
      • Common uses: BMP contains a maximum amount of details while PNGs are good for small illustrations, sketches, drawings, logos and icons.
      • Quality: No difference
      • Transparency: PNG supports transparency while BMP doesn't
  • Some comparison about the ratio
    • 11/8.5=1.29 (A4 paper)
    • 8/6=1.33 (plot output)
    • 1440/900=1.6 (my display)
  • Setting resolution and aspect ratios in R
  • The difference of res parameter for a simple plot. How to change the resolution of a plot in base R?
  • High Resolution Figures in R.
  • High resolution graphics with R
  • R plot: size and resolution
  • How can I increase the resolution of my plot in R?, devEMF package
  • See Images -> Anti-alias.
  • How to check DPI on PNG
    • The width of a PNG file in terms of inches cannot be determined directly from the file itself, as the file contains pixel dimensions, not physical dimensions. However, you can calculate the width in inches if you know the resolution (DPI, dots per inch) of the image. Remember that converting pixel measurements to physical measurements like inches involves a specific resolution (DPI), and different devices may display the same image at different sizes due to having different resolutions.
  • Cairo case.

PowerPoint

  • For PP presentation, I found it is useful to use svg() to generate a small size figure. Then when we enlarge the plot, the text font size can be enlarged too. According to svg, by default, width = 7, height = 7, pointsize = 12, family = sans.
  • Try the following code. The font size is the same for both plots/files. However, the first plot can be enlarged without losing its quality.
    svg("svg4.svg", width=4, height=4)
    plot(1:10, main="width=4, height=4")
    dev.off()
    
    svg("svg7.svg", width=7, height=7) # default
    plot(1:10, main="width=7, height=7")
    dev.off()
    

magick

https://cran.r-project.org/web/packages/magick/

See an example here I created.

Cairo

See White strips problem in png() or tiff().

geDevices

cairoDevice

PS. Not sure the advantage of functions in this package compared to R's functions (eg. Cairo_svg() vs svg()).

For ubuntu OS, we need to install 2 libraries and 1 R package RGtk2.

sudo apt-get install libgtk2.0-dev libcairo2-dev

On Windows OS, we may got the error: unable to load shared object 'C:/Program Files/R/R-3.0.2/library/cairoDevice/libs/x64/cairoDevice.dll' . We need to follow the instruction in here.

dpi requirement for publication

For import into PDF-incapable programs (MS Office)

sketcher: photo to sketch effects

https://htsuda.net/sketcher/

httpgd

igraph

R web -> igraph

Identifying dependencies of R functions and scripts

https://stackoverflow.com/questions/8761857/identifying-dependencies-of-r-functions-and-scripts

library(mvbutils)
foodweb(where = "package:batr")

foodweb( find.funs("package:batr"), prune="survRiskPredict", lwd=2)

foodweb( find.funs("package:batr"), prune="classPredict", lwd=2)

iterators

Iterator is useful over for-loop if the data is already a collection. It can be used to iterate over a vector, data frame, matrix, file

Iterator can be combined to use with foreach package http://www.exegetic.biz/blog/2013/11/iterators-in-r/ has more elaboration.

Colors

  • scales package. This is used in ggplot2 package.
  • colorspace: A Toolbox for Manipulating and Assessing Colors and Palettes. Popular! Many reverse imports/suggests; e.g. ComplexHeatmap. See my ggplot2 page.
    hcl_palettes(plot = TRUE) # a quick overview
    hcl_palettes(palette = "Dark 2", n=5, plot = T)
    q4 <- qualitative_hcl(4, palette = "Dark 3")
    
  • convert hex value to color names
    library(plotrix)
    sapply(rainbow(4), color.id) # color.id is a function
              # it is used to identify closest match to a color
    sapply(palette(), color.id)
    sapply(RColorBrewer::brewer.pal(4, "Set1"), color.id)
    

Below is an example using the option scale_fill_brewer(palette = "Paired"). See the source code at gist. Note that only set1 and set3 palettes in qualitative scheme can support up to 12 classes.

According to the information from the colorbrew website, qualitative schemes do not imply magnitude differences between legend classes, and hues are used to create the primary visual differences between classes.

File:GgplotPalette.svg

colortools

Tools that allow users generate color schemes and palettes

colourpicker

A Colour Picker Tool for Shiny and for Selecting Colours in Plots

eyedroppeR

Select colours from an image in R with {eyedroppeR}

rex

Friendly Regular Expressions

formatR

The best strategy to avoid failure is to put comments in complete lines or after complete R expressions.

See also this discussion on stackoverflow talks about R code reformatting.

library(formatR)
tidy_source("Input.R", file = "output.R", width.cutoff=70)
tidy_source("clipboard") 
# default width is getOption("width") which is 127 in my case.

Some issues

  • Comments appearing at the beginning of a line within a long complete statement. This will break tidy_source().
cat("abcd",
    # This is my comment
    "defg")

will result in

> tidy_source("clipboard")
Error in base::parse(text = code, srcfile = NULL) : 
  3:1: unexpected string constant
2: invisible(".BeGiN_TiDy_IdEnTiFiEr_HaHaHa# This is my comment.HaHaHa_EnD_TiDy_IdEnTiFiEr")
3: "defg"
   ^
  • Comments appearing at the end of a line within a long complete statement won't break tidy_source() but tidy_source() cannot re-locate/tidy the comma sign.
cat("abcd"
    ,"defg"   # This is my comment
  ,"ghij")

will become

cat("abcd", "defg"  # This is my comment
, "ghij") 

Still bad!!

  • Comments appearing at the end of a line within a long complete statement breaks tidy_source() function. For example,
cat("</p>",
	"<HR SIZE=5 WIDTH=\"100%\" NOSHADE>",
	ifelse(codeSurv == 0,"<h3><a name='Genes'><b><u>Genes which are differentially expressed among classes:</u></b></a></h3>", #4/9/09
	                     "<h3><a name='Genes'><b><u>Genes significantly associated with survival:</u></b></a></h3>"), 
	file=ExternalFileName, sep="\n", append=T)

will result in

> tidy_source("clipboard", width.cutoff=70)
Error in base::parse(text = code, srcfile = NULL) : 
  3:129: unexpected SPECIAL
2: "<HR SIZE=5 WIDTH=\"100%\" NOSHADE>" ,
3: ifelse ( codeSurv == 0 , "<h3><a name='Genes'><b><u>Genes which are differentially expressed among classes:</u></b></a></h3>" , %InLiNe_IdEnTiFiEr%
  • width.cutoff parameter is not always working. For example, there is no any change for the following snippet though I hope it will move the cat() to the next line.
if (codePF & !GlobalTest & !DoExactPermTest) cat(paste("Multivariate Permutations test was computed based on", 
    NumPermutations, "random permutations"), "<BR>", " ", file = ExternalFileName, 
    sep = "\n", append = T)
  • It merges lines though I don't always want to do that. For example
cat("abcd"
    ,"defg"  
  ,"ghij")

will become

cat("abcd", "defg", "ghij") 

styler

https://cran.r-project.org/web/packages/styler/index.html Pretty-prints R code without changing the user's formatting intent.

Download papers

biorxivr

Search and Download Papers from the bioRxiv Preprint Server (biology)

aRxiv

Interface to the arXiv API

pdftools

aside: set it aside

An RStudio addin to run long R commands aside your current session.

Teaching

  • smovie: Some Movies to Illustrate Concepts in Statistics

Organize R research project

How to save (and load) datasets in R (.RData vs .Rds file)

How to save (and load) datasets in R: An overview

Naming convention

Efficient Data Management in R

Efficient Data Management in R. .Rprofile, renv package and dplyr package.

Text to speech

Text-to-Speech with the googleLanguageR package

Speech to text

https://github.com/ggerganov/whisper.cpp and an R package audio.whisper

Weather data

logR

https://github.com/jangorecki/logR

Progress bar

https://github.com/r-lib/progress#readme

Configurable Progress bars, they may include percentage, elapsed time, and/or the estimated completion time. They work in terminals, in 'Emacs' 'ESS', 'RStudio', 'Windows' 'Rgui' and the 'macOS'.

cron

beepr: Play A Short Sound

https://www.rdocumentation.org/packages/beepr/versions/1.3/topics/beep. Try sound=3 "fanfare", 4 "complete", 5 "treasure", 7 "shotgun", 8 "mario".

utils package

https://www.rdocumentation.org/packages/utils/versions/3.6.2

tools package

Different ways of using R

Extending R by John M. Chambers (2016)

10 things R can do that might surprise you

https://simplystatistics.org/2019/03/13/10-things-r-can-do-that-might-surprise-you/

R call C/C++

Mainly talks about .C() and .Call().

Note that scalars and arrays must be passed using pointers. So if we want to access a function not exported from a package, we may need to modify the function to make the arguments as pointers.

.Call

Be sure to add the PACKAGE parameter to avoid an error like

cvfit <- cv.grpsurvOverlap(X, Surv(time, event), group, 
                            cv.ind = cv.ind, seed=1, penalty = 'cMCP')
Error in .Call("standardize", X) : 
  "standardize" not resolved from current namespace (grpreg)

NAMESPACE file & useDynLib

(From Writing R Extensions manual) Loading is most often done automatically based on the useDynLib() declaration in the NAMESPACE file, but may be done explicitly via a call to library.dynam(). This has the form

library.dynam("libname", package, lib.loc) 

library.dynam.unload()

gcc

Coping with varying `gcc` versions and capabilities in R packages

Primitive functions

Primitive Functions List

SEXP

Some examples from packages

  • sva package has one C code function

R call Fortran

Embedding R

An very simple example (do not return from shell) from Writing R Extensions manual

The command-line R front-end, R_HOME/bin/exec/R, is one such example. Its source code is in file <src/main/Rmain.c>.

This example can be run by

R_HOME/bin/R CMD R_HOME/bin/exec/R

Note:

  1. R_HOME/bin/exec/R is the R binary. However, it couldn't be launched directly unless R_HOME and LD_LIBRARY_PATH are set up. Again, this is explained in Writing R Extension manual.
  2. R_HOME/bin/R is a shell-script front-end where users can invoke it. It sets up the environment for the executable. It can be copied to /usr/local/bin/R. When we run R_HOME/bin/R, it actually runs R_HOME/bin/R CMD R_HOME/bin/exec/R (see line 259 of R_HOME/bin/R as in R 3.0.2) so we know the important role of R_HOME/bin/exec/R.

More examples of embedding can be found in tests/Embedding directory. Read <index.html> for more information about these test examples.

An example from Bioconductor workshop

Example: Create embed.c file. Then build the executable. Note that I don't need to create R_HOME variable.

cd 
tar xzvf 
cd R-3.0.1
./configure --enable-R-shlib
make
cd tests/Embedding
make
~/R-3.0.1/bin/R CMD ./Rtest

nano embed.c
# Using a single line will give an error and cannot not show the real problem.
# ../../bin/R CMD gcc -I../../include -L../../lib -lR embed.c
# A better way is to run compile and link separately
gcc -I../../include -c embed.c
gcc -o embed embed.o -L../../lib -lR -lRblas
../../bin/R CMD ./embed

Note that if we want to call the executable file ./embed directly, we shall set up R environment by specifying R_HOME variable and including the directories used in linking R in LD_LIBRARY_PATH. This is based on the inform provided by Writing R Extensions.

export R_HOME=/home/brb/Downloads/R-3.0.2
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/brb/Downloads/R-3.0.2/lib
./embed # No need to include R CMD in front.

Question: Create a data frame in C? Answer: Use data.frame() via an eval() call from C. Or see the code is stats/src/model.c, as part of model.frame.default. Or using Rcpp as here.

Reference http://bioconductor.org/help/course-materials/2012/Seattle-Oct-2012/AdvancedR.pdf

Create a Simple Socket Server in R

This example is coming from this paper.

Create an R function

simpleServer <- function(port=6543)
{
  sock <- socketConnection ( port=port , server=TRUE)
  on.exit(close( sock ))
  cat("\nWelcome to R!\nR>" ,file=sock )
  while(( line <- readLines ( sock , n=1)) != "quit")
  {
    cat(paste("socket >" , line , "\n"))
    out<- capture.output (try(eval(parse(text=line ))))
    writeLines ( out , con=sock )
    cat("\nR> " ,file =sock )
  }
}

Then run simpleServer(). Open another terminal and try to communicate with the server

$ telnet localhost 6543
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

Welcome to R!
R> summary(iris[, 3:5])
  Petal.Length    Petal.Width          Species  
 Min.   :1.000   Min.   :0.100   setosa    :50  
 1st Qu.:1.600   1st Qu.:0.300   versicolor:50  
 Median :4.350   Median :1.300   virginica :50  
 Mean   :3.758   Mean   :1.199                  
 3rd Qu.:5.100   3rd Qu.:1.800                  
 Max.   :6.900   Max.   :2.500                  

R> quit
Connection closed by foreign host.

Rserve

Note the way of launching Rserve is like the way we launch C program when R was embedded in C. See Example from Bioconductor workshop.

See my Rserve page.

outsider

(Commercial) StatconnDcom

R.NET

rJava

Terminal

# jdk 7
sudo apt-get install openjdk-7-*
update-alternatives --config java
# oracle jdk 8
sudo add-apt-repository -y ppa:webupd8team/java
sudo apt-get update
echo debconf shared/accepted-oracle-license-v1-1 select true | sudo debconf-set-selections
echo debconf shared/accepted-oracle-license-v1-1 seen true | sudo debconf-set-selections
sudo apt-get -y install openjdk-8-jdk

and then run the following (thanks to http://stackoverflow.com/questions/12872699/error-unable-to-load-installed-packages-just-now) to fix an error: libjvm.so: cannot open shared object file: No such file or directory.

  • Create the file /etc/ld.so.conf.d/java.conf with the following entries:
/usr/lib/jvm/java-8-oracle/jre/lib/amd64
/usr/lib/jvm/java-8-oracle/jre/lib/amd64/server
  • And then run sudo ldconfig

Now go back to R

install.packages("rJava")

Done!

If above does not work, a simple way is by (under Ubuntu) running

sudo apt-get install r-cran-rjava

which will create new package 'default-jre' (under /usr/lib/jvm) and 'default-jre-headless'.

RCaller

RApache

Rscript, arguments and commandArgs()

Passing arguments to an R script from command lines Syntax:

$ Rscript --help
Usage: /path/to/Rscript [--options] [-e expr [-e expr2 ...] | file] [args]

Example:

args = commandArgs(trailingOnly=TRUE)
# test if there is at least one argument: if not, return an error
if (length(args)==0) {
  stop("At least one argument must be supplied (input file).n", call.=FALSE)
} else if (length(args)==1) {
  # default output file
  args[2] = "out.txt"
}
cat("args[1] = ", args[1], "\n")
cat("args[2] = ", args[2], "\n")
Rscript --vanilla sillyScript.R iris.txt out.txt
# args[1] =  iris.txt 
# args[2] =  out.txt

Rscript, #! Shebang and optparse package

littler

Provides hash-bang (#!) capability for R

FAQs:

root@ed5f80320266:/# ls -l /usr/bin/{r,R*}
# R 3.5.2 docker container
-rwxr-xr-x 1 root root 82632 Jan 26 18:26 /usr/bin/r        # binary, can be used for 'shebang' lines, r --help
                                              # Example: r --verbose -e "date()"

-rwxr-xr-x 1 root root  8722 Dec 20 11:35 /usr/bin/R        # text, R --help
                                              # Example: R -q -e "date()"

-rwxr-xr-x 1 root root 14552 Dec 20 11:35 /usr/bin/Rscript  # binary, can be used for 'shebang' lines, Rscript --help
                                              # It won't show the startup message when it is used in the command line.
                                              # Example: Rscript -e "date()"

We can install littler using two ways.

  • install.packages("littler"). This will install the latest version but the binary 'r' program is only available under the package/bin directory (eg ~/R/x86_64-pc-linux-gnu-library/3.4/littler/bin/r). You need to create a soft link in order to access it globally.
  • sudo apt install littler. This will install 'r' globally; however, the installed version may be old.

After the installation, vignette contains several examples. The off-line vignette has a table of contents. Nice! The web version of examples does not have the TOC.

r was not meant to run interactively like R. See man r.

RInside: Embed R in C++

See RInside

(From RInside documentation) The RInside package makes it easier to embed R in your C++ applications. There is no code you would execute directly from the R environment. Rather, you write C++ programs that embed R which is illustrated by some the included examples.

The included examples are armadillo, eigen, mpi, qt, standard, threads and wt.

To run 'make' when we don't have a global R, we should modify the file <Makefile>. Also if we just want to create one executable file, we can do, for example, 'make rinside_sample1'.

To run any executable program, we need to specify LD_LIBRARY_PATH variable, something like

export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/home/brb/Downloads/R-3.0.2/lib 

The real build process looks like (check <Makefile> for completeness)

g++ -I/home/brb/Downloads/R-3.0.2/include \
    -I/home/brb/Downloads/R-3.0.2/library/Rcpp/include \
    -I/home/brb/Downloads/R-3.0.2/library/RInside/include -g -O2 -Wall \
    -I/usr/local/include   \
    rinside_sample0.cpp  \
    -L/home/brb/Downloads/R-3.0.2/lib -lR  -lRblas -lRlapack \
    -L/home/brb/Downloads/R-3.0.2/library/Rcpp/lib -lRcpp \
    -Wl,-rpath,/home/brb/Downloads/R-3.0.2/library/Rcpp/lib \
    -L/home/brb/Downloads/R-3.0.2/library/RInside/lib -lRInside \
    -Wl,-rpath,/home/brb/Downloads/R-3.0.2/library/RInside/lib \
    -o rinside_sample0

Hello World example of embedding R in C++.

#include <RInside.h>                    // for the embedded R via RInside

int main(int argc, char *argv[]) {

    RInside R(argc, argv);              // create an embedded R instance 

    R["txt"] = "Hello, world!\n";	// assign a char* (string) to 'txt'

    R.parseEvalQ("cat(txt)");           // eval the init string, ignoring any returns

    exit(0);
}

The above can be compared to the Hello world example in Qt.

#include <QApplication.h>
#include <QPushButton.h>

int main( int argc, char **argv )
{
    QApplication app( argc, argv );

    QPushButton hello( "Hello world!", 0 );
    hello.resize( 100, 30 );

    app.setMainWidget( &hello );
    hello.show();

    return app.exec();
}

RFortran

RFortran is an open source project with the following aim:

To provide an easy to use Fortran software library that enables Fortran programs to transfer data and commands to and from R.

It works only on Windows platform with Microsoft Visual Studio installed:(

Call R from other languages

C

Using R from C/C++

Error: “not resolved from current namespace” error, when calling C routines from R

Solution: add getNativeSymbolInfo() around your C/Fortran symbols. Search Google:r dyn.load not resolved from current namespace

JRI

http://www.rforge.net/JRI/

ryp2

http://rpy.sourceforge.net/rpy2.html

Create a standalone Rmath library

R has many math and statistical functions. We can easily use these functions in our C/C++/Fortran. The definite guide of doing this is on Chapter 9 "The standalone Rmath library" of R-admin manual.

Here is my experience based on R 3.0.2 on Windows OS.

Create a static library <libRmath.a> and a dynamic library <Rmath.dll>

Suppose we have downloaded R source code and build R from its source. See Build_R_from_its_source. Then the following 2 lines will generate files <libRmath.a> and <Rmath.dll> under C:\R\R-3.0.2\src\nmath\standalone directory.

cd C:\R\R-3.0.2\src\nmath\standalone
make -f Makefile.win

Use Rmath library in our code

set CPLUS_INCLUDE_PATH=C:\R\R-3.0.2\src\include
set LIBRARY_PATH=C:\R\R-3.0.2\src\nmath\standalone
# It is not LD_LIBRARY_PATH in above.

# Created <RmathEx1.cpp> from the book "Statistical Computing in C++ and R" web site
# http://math.la.asu.edu/~eubank/CandR/ch4Code.cpp
# It is OK to save the cpp file under any directory.

# Force to link against the static library <libRmath.a>
g++ RmathEx1.cpp -lRmath -lm -o RmathEx1.exe
# OR
g++ RmathEx1.cpp -Wl,-Bstatic -lRmath -lm -o RmathEx1.exe

# Force to link against dynamic library <Rmath.dll>
g++ RmathEx1.cpp Rmath.dll -lm -o RmathEx1Dll.exe

Test the executable program. Note that the executable program RmathEx1.exe can be transferred to and run in another computer without R installed. Isn't it cool!

c:\R>RmathEx1
Enter a argument for the normal cdf:
1
Enter a argument for the chi-squared cdf:
1
Prob(Z <= 1) = 0.841345
Prob(Chi^2 <= 1)= 0.682689

Below is the cpp program <RmathEx1.cpp>.

//RmathEx1.cpp
#define MATHLIB_STANDALONE 
#include <iostream>
#include "Rmath.h"

using std::cout; using std::cin; using std::endl;

int main()
{
  double x1, x2;
  cout << "Enter a argument for the normal cdf:" << endl;
  cin >> x1;
  cout << "Enter a argument for the chi-squared cdf:" << endl;
  cin >> x2;

  cout << "Prob(Z <= " << x1 << ") = " << 
    pnorm(x1, 0, 1, 1, 0)  << endl;
  cout << "Prob(Chi^2 <= " << x2 << ")= " << 
    pchisq(x2, 1, 1, 0) << endl;
  return 0;
}

Calling R.dll directly

See Chapter 8.2.2 of R Extensions. This is related to embedding R under Windows. The file <R.dll> on Windows is like <libR.so> on Linux.

Create HTML report

ReportingTools (Jason Hackney) from Bioconductor. See Genome->ReportingTools.

htmlTable package

The htmlTable package is intended for generating tables using HTML formatting. This format is compatible with Markdown when used for HTML-output. The most basic table can easily be created by just passing a matrix or a data.frame to the htmlTable-function.

formattable

htmltab package

This package is NOT used to CREATE html report but EXTRACT html table.

ztable package

Makes zebra-striped tables (tables with alternating row colors) in LaTeX and HTML formats easily from a data.frame, matrix, lm, aov, anova, glm or coxph objects.

Create academic report

reports package in CRAN and in github repository. The youtube video gives an overview of the package.

Create pdf and epub files

# Idea:
#        knitr        pdflatex
#   rnw -------> tex ----------> pdf
library(knitr)
knit("example.rnw") # create example.tex file
  • A very simple example <002-minimal.Rnw> from yihui.name works fine on linux.
git clone https://github.com/yihui/knitr-examples.git
  • <knitr-minimal.Rnw>. I have no problem to create pdf file on Windows but still cannot generate pdf on Linux from tex file. Some people suggested to run sudo apt-get install texlive-fonts-recommended to install missing fonts. It works!

To see a real example, check out DESeq2 package (inst/doc subdirectory). In addition to DESeq2, I also need to install DESeq, BiocStyle, airway, vsn, gplots, and pasilla packages from Bioconductor. Note that, it is best to use sudo/admin account to install packages.

Or starts with markdown file. Download the example <001-minimal.Rmd> and remove the last line of getting png file from internet.

# Idea:
#        knitr        pandoc
#   rmd -------> md ----------> pdf

git clone https://github.com/yihui/knitr-examples.git
cd knitr-examples
R -e "library(knitr); knit('001-minimal.Rmd')"
pandoc 001-minimal.md -o 001-minimal.pdf # require pdflatex to be installed !!

To create an epub file (not success yet on Windows OS, missing figures on Linux OS)

# Idea:
#        knitr        pandoc
#   rnw -------> tex ----------> markdown or epub

library(knitr)
knit("DESeq2.Rnw") # create DESeq2.tex
system("pandoc  -f latex -t markdown -o DESeq2.md DESeq2.tex")

Convert tex to epub

kable() for tables

Create Tables In LaTeX, HTML, Markdown And ReStructuredText

Create Word report

Using the power of Word

How to go from R to nice tables in Microsoft Word

knitr + pandoc

It is better to create rmd file in RStudio. Rstudio provides a template for rmd file and it also provides a quick reference to R markdown language.

# Idea:
#        knitr       pandoc
#   rmd -------> md --------> docx
library(knitr)
knit2html("example.rmd") #Create md and html files

and then

FILE <- "example"
system(paste0("pandoc -o ", FILE, ".docx ", FILE, ".md"))

Note. For example reason, if I play around the above 2 commands for several times, the knit2html() does not work well. However, if I click 'Knit HTML' button on the RStudio, it then works again.

Another way is

library(pander)
name = "demo"
knit(paste0(name, ".Rmd"), encoding = "utf-8")
Pandoc.brew(file = paste0(name, ".md"), output = paste0(-name, "docx"), convert = "docx")

Note that once we have used knitr command to create a md file, we can use pandoc shell command to convert it to different formats:

  • A pdf file: pandoc -s report.md -t latex -o report.pdf
  • A html file: pandoc -s report.md -o report.html (with the -c flag html files can be added easily)
  • Openoffice: pandoc report.md -o report.odt
  • Word docx: pandoc report.md -o report.docx

We can also create the epub file for reading on Kobo ereader. For example, download this file and save it as example.Rmd. I need to remove the line containing the link to http://i.imgur.com/RVNmr.jpg since it creates an error when I run pandoc (not sure if it is the pandoc version I have is too old). Now we just run these 2 lines to get the epub file. Amazing!

knit("example.Rmd")
pandoc("example.md", format="epub")

PS. If we don't remove the link, we will get an error message (pandoc 1.10.1 on Windows 7)

> pandoc("Rmd_to_Epub.md", format="epub")
executing pandoc   -f markdown -t epub -o Rmd_to_Epub.epub "Rmd_to_Epub.utf8md"
pandoc.exe: .\.\http://i.imgur.com/RVNmr.jpg: openBinaryFile: invalid argument (Invalid argument)
Error in (function (input, format, ext, cfg)  : conversion failed
In addition: Warning message:
running command 'pandoc   -f markdown -t epub -o Rmd_to_Epub.epub "Rmd_to_Epub.utf8md"' had status 1

pander

Try pandoc[1] with a minimal reproducible example, you might give a try to my "pander" package [2] too:

library(pander)
Pandoc.brew(system.file('examples/minimal.brew', package='pander'),
            output = tempfile(), convert = 'docx')

Where the content of the "minimal.brew" file is something you might have got used to with Sweave - although it's using "brew" syntax instead. See the examples of pander [3] for more details. Please note that pandoc should be installed first, which is pretty easy on Windows.

  1. http://johnmacfarlane.net/pandoc/
  2. http://rapporter.github.com/pander/
  3. http://rapporter.github.com/pander/#examples

R2wd

Use R2wd package. However, only 32-bit R is allowed and sometimes it can not produce all 'table's.

> library(R2wd)
> wdGet()
Loading required package: rcom
Loading required package: rscproxy
rcom requires a current version of statconnDCOM installed.
To install statconnDCOM type
     installstatconnDCOM()

This will download and install the current version of statconnDCOM

You will need a working Internet connection
because installation needs to download a file.
Error in if (wdapp[["Documents"]][["Count"]] == 0) wdapp[["Documents"]]$Add() : 
  argument is of length zero 

The solution is to launch 32-bit R instead of 64-bit R since statconnDCOM does not support 64-bit R.

Convert from pdf to word

The best rendering of advanced tables is done by converting from pdf to Word. See http://biostat.mc.vanderbilt.edu/wiki/Main/SweaveConvert

rtf

Use rtf package for Rich Text Format (RTF) Output.

xtable

Package xtable will produce html output.

print(xtable(X), type="html")

If you save the file and then open it with Word, you will get serviceable results. I've had better luck copying the output from xtable and pasting it into Excel.

officer

  • CRAN. Microsoft Word, Microsoft Powerpoint and HTML documents generation from R.
  • The gist includes a comprehensive example that encompasses various elements such as sections, subsections, and tables. It also incorporates a detailed paragraph, along with visual representations created using base R plots and ggplots.
  • Add a line space
    doc <- body_add_par(doc, "")
    
    # Function to add n line spaces
    body_add_par_n <- function (doc, n) {
      for(i in 1:n){
        doc <- body_add_par(doc, "")
      }
      return(doc)
    }
    body_add_par_n(3)
    
  • Figures from the documentation of officeverse.
  • See Data frame to word table?.
  • See Office page for some code.
  • How to read and create Word Documents in R where we can extracting tables from Word Documents.
    x = read_docx("myfile.docx")
    content <- docx_summary(x) # a vector
    grep("nlme", content$text, ignore.case = T, value = T)
    

Powerpoint

PDF manipulation

staplr

R Graphs Gallery

COM client or server

Client

Server

RDCOMServer

Use R under proxy

http://support.rstudio.org/help/kb/faq/configuring-r-to-use-an-http-proxy

RStudio

  • Github
  • Installing RStudio (1.0.44) on Ubuntu will not install Java even the source code contains 37.5% Java??
  • Preview

rstudio.cloud

https://rstudio.cloud/

Launch RStudio

Multiple versions of R

Create .Rproj file

If you have an existing package that doesn't have an .Rproj file, you can use devtools::use_rstudio("path/to/package") to add it.

With an RStudio project file, you can

  • Restore .RData into workspace at startup
  • Save workspace to .RData on exit (or save.image("Robj.RData") & load("Robj.RData"))
  • Always save history (even if no saving .RData, savehistory(".Rhistory") & loadhistory(".Rhistory"))
  • etc

package search

https://github.com/RhoInc/CRANsearcher

Git

Visual Studio

R and Python support now built in to Visual Studio 2017

List files using regular expression

  • Extension
list.files(pattern = "\\.txt$")

where the dot (.) is a metacharacter. It is used to refer to any character.

  • Start with
list.files(pattern = "^Something")

Using Sys.glob()"' as

> Sys.glob("~/Downloads/*.txt")
[1] "/home/brb/Downloads/ip.txt"       "/home/brb/Downloads/valgrind.txt"

Hidden tool: rsync in Rtools

c:\Rtools\bin>rsync -avz "/cygdrive/c/users/limingc/Downloads/a.exe" "/cygdrive/c/users/limingc/Documents/"
sending incremental file list
a.exe

sent 323142 bytes  received 31 bytes  646346.00 bytes/sec
total size is 1198416  speedup is 3.71

c:\Rtools\bin>

Unforunately, if the destination is a network drive, I could get a permission denied (13) error. See also rsync file permissions on windows.

Install rgdal package (geospatial Data) on ubuntu

Terminal

sudo apt-get install libgdal1-dev libproj-dev # https://stackoverflow.com/a/44389304
sudo apt-get install libgdal1i # Ubuntu 16.04 https://stackoverflow.com/a/12143411

R

install.packages("rgdal")

Install sf package

I got the following error even I have installed some libraries.

checking GDAL version >= 2.0.1... no
configure: error: sf is not compatible with GDAL versions below 2.0.1

Then I follow the instruction here

sudo apt remove libgdal-dev
sudo apt remove libproj-dev
sudo apt remove gdal-bin
sudo add-apt-repository ppa:ubuntugis/ubuntugis-stable

sudo apt update
sudo apt-cache policy libgdal-dev # Make sure a version >= 2.0 appears 

sudo apt install libgdal-dev # works on ubuntu 20.04 too
                             # no need the previous lines

Database

RSQLite

Creating a new database:

library(DBI)

mydb <- dbConnect(RSQLite::SQLite(), "my-db.sqlite")
dbDisconnect(mydb)
unlink("my-db.sqlite")

# temporary database
mydb <- dbConnect(RSQLite::SQLite(), "")
dbDisconnect(mydb)

Loading data:

mydb <- dbConnect(RSQLite::SQLite(), "")
dbWriteTable(mydb, "mtcars", mtcars)
dbWriteTable(mydb, "iris", iris)

dbListTables(mydb)

dbListFields(con, "mtcars")

dbReadTable(con, "mtcars")

Queries:

dbGetQuery(mydb, 'SELECT * FROM mtcars LIMIT 5')

dbGetQuery(mydb, 'SELECT * FROM iris WHERE "Sepal.Length" < 4.6')

dbGetQuery(mydb, 'SELECT * FROM iris WHERE "Sepal.Length" < :x', params = list(x = 4.6))

res <- dbSendQuery(con, "SELECT * FROM mtcars WHERE cyl = 4")
dbFetch(res)

Batched queries:

dbClearResult(rs)
rs <- dbSendQuery(mydb, 'SELECT * FROM mtcars')
while (!dbHasCompleted(rs)) {
  df <- dbFetch(rs, n = 10)
  print(nrow(df))
}

dbClearResult(rs)

Multiple parameterised queries:

rs <- dbSendQuery(mydb, 'SELECT * FROM iris WHERE "Sepal.Length" = :x')
dbBind(rs, param = list(x = seq(4, 4.4, by = 0.1)))
nrow(dbFetch(rs))
#> [1] 4
dbClearResult(rs)

Statements:

dbExecute(mydb, 'DELETE FROM iris WHERE "Sepal.Length" < 4')
#> [1] 0
rs <- dbSendStatement(mydb, 'DELETE FROM iris WHERE "Sepal.Length" < :x')
dbBind(rs, param = list(x = 4.5))
dbGetRowsAffected(rs)
#> [1] 4
dbClearResult(rs)

sqldf

Manipulate R data frames using SQL. Depends on RSQLite. A use of gsub, reshape2 and sqldf with healthcare data

RPostgreSQL

RMySQL

MongoDB

odbc

RODBC

DBI

dbplyr

Create a new SQLite database:

surveys <- read.csv("data/surveys.csv")
plots <- read.csv("data/plots.csv")

my_db_file <- "portal-database.sqlite"
my_db <- src_sqlite(my_db_file, create = TRUE)

copy_to(my_db, surveys)
copy_to(my_db, plots)
my_db

Connect to a database:

download.file(url = "https://ndownloader.figshare.com/files/2292171",
              destfile = "portal_mammals.sqlite", mode = "wb")

library(dbplyr)
library(dplyr)
mammals <- src_sqlite("portal_mammals.sqlite")

Querying the database with the SQL syntax:

tbl(mammals, sql("SELECT year, species_id, plot_id FROM surveys"))

Querying the database with the dplyr syntax:

surveys <- tbl(mammals, "surveys")
surveys %>%
    select(year, species_id, plot_id)
head(surveys, n = 10)

show_query(head(surveys, n = 10)) # show which SQL commands are actually sent to the database

Simple database queries:

surveys %>%
  filter(weight < 5) %>%
  select(species_id, sex, weight)

Laziness (instruct R to stop being lazy):

data_subset <- surveys %>%
  filter(weight < 5) %>%
  select(species_id, sex, weight) %>%
  collect()

Complex database queries:

plots <- tbl(mammals, "plots")
plots # # The plot_id column features in the plots table

surveys # The plot_id column also features in the surveys table

# Join databases method 1
plots %>%
  filter(plot_id == 1) %>%
  inner_join(surveys) %>%
  collect()

NoSQL

nodbi: the NoSQL Database Connector

Github

R source

https://github.com/wch/r-source/ Daily update, interesting, should be visited every day. Clicking 1000+ commits to look at daily changes.

If we are interested in a certain branch (say 3.2), look for R-3-2-branch.

R packages (only) source (metacran)

Bioconductor packages source

Announcement, https://github.com/Bioconductor-mirror

Send local repository to Github in R by using reports package

http://www.youtube.com/watch?v=WdOI_-aZV0Y

My collection

How to download

Clone ~ Download.

  • Command line
git clone https://gist.github.com/4484270.git

This will create a subdirectory called '4484270' with all cloned files there.

  • Within R
library(devtools)
source_gist("4484270")

or First download the json file from

https://api.github.com/users/MYUSERLOGIN/gists

and then

library(RJSONIO)
x <- fromJSON("~/Downloads/gists.json")
setwd("~/Downloads/")
gist.id <- lapply(x, "[[", "id")
lapply(gist.id, function(x){
  cmd <- paste0("git clone https://gist.github.com/", x, ".git")
  system(cmd)
})

Jekyll

An Easy Start with Jekyll, for R-Bloggers

Connect R with Arduino

Android App

Common plots tips

Create an empty plot

plot.new()

Overlay plots

How to Overlay Plots in R-Quick Guide with Example.

#Step1:-create scatterplot
plot(x1, y1)
#Step 2:-overlay line plot
lines(x2, y2)
#Step3:-overlay scatterplot
points(x2, y2)

Save the par() and restore it

Example 1: Don't use old.par <- par() directly. no.readonly = FALSE by default. * The `no.readonly = TRUE` argument in the par() function in R is used to get the full list of graphical parameters that can be restored.

  • When you call `par()` with no arguments or `par(no.readonly = TRUE)`, it returns an invisible named list of all the graphical parameters. This includes both parameters that can be set and those that are read-only.
  • If we use par(old.par) where old.par <- par(), we will get several warning messages like 'In par(op) : graphical parameter "cin" cannot be set'.
old.par <- par(no.readonly = TRUE); par(mar = c(5, 4, 4, 2) - 2)  # OR in one step
old.par <- par(mar = c(5, 4, 4, 2) - 2)
## do plotting stuff with new settings
par(old.par)

Example 2: Use it inside a function with the on.exit(0 function.

ex <- function() {
   old.par <- par(no.readonly = TRUE) # all par settings which
                                      # could be changed.
   on.exit(par(old.par))
   ## ... do lots of par() settings and plots
   ## ...
   invisible() #-- now,  par(old.par)  will be executed
}

Example 3: It seems par() inside a function will affect the global environment. But if we use dev.off(), it will reset all parameters.

ex <- function() { par(mar=c(5,4,4,1)) }
ex()
par()$mar
ex = function() { png("~/Downloads/test.png"); par(mar=c(5,4,4,1)); dev.off()}
ex()
par()$mar

Grouped boxplots

Weather Time Line

The plot looks similar to a boxplot though it is not. See a screenshot on Android by Sam Ruston.

Horizontal bar plot

library(ggplot2)
dtf <- data.frame(x = c("ETB", "PMA", "PER", "KON", "TRA", 
                        "DDR", "BUM", "MAT", "HED", "EXP"),
                  y = c(.02, .11, -.01, -.03, -.03, .02, .1, -.01, -.02, 0.06))
ggplot(dtf, aes(x, y)) +
  geom_bar(stat = "identity", aes(fill = x), show.legend = FALSE) + 
  coord_flip() + xlab("") + ylab("Fold Change")   

File:Ggplot2bar.svg

Include bar values in a barplot

Use text().

Or use geom_text() if we are using the ggplot2 package. See an example here or this.

For stacked barplot, see this post.

Grouped barplots

library(ggplot2)
# mydata <- data.frame(OUTGRP, INGRP, value)
ggplot(mydata, aes(fill=INGRP, y=value, x=OUTGRP)) + 
       geom_bar(position="dodge", stat="identity")
> 1 - 2*(1-pnorm(1))
[1] 0.6826895
> 1 - 2*(1-pnorm(1.96))
[1] 0.9500042

Unicode symbols

Mind reader game, and Unicode symbols

Math expression

# Expressions
plot(x,y, xlab = expression(hat(x)[t]),
     ylab = expression(phi^{rho + a}),
     main = "Pure Expressions")

# Superscript
plot(1:10, main = expression("My Title"^2)) 
# Subscript
plot(1:10, main = expression("My Title"[2]))  

# Expressions with Spacing
# '~' is to add space and '*' is to squish characters together
plot(1:10, xlab= expression(Delta * 'C'))
plot(x,y, xlab = expression(hat(x)[t] ~ z ~ w),
     ylab = expression(phi^{rho + a} * z * w),
     main = "Pure Expressions with Spacing")

# Expressions with Text
plot(x,y, 
     xlab = expression(paste("Text here ", hat(x), " here ", z^rho, " and here")), 
     ylab = expression(paste("Here is some text of ", phi^{rho})), 
     main = "Expressions with Text")

# Substituting Expressions
plot(x,y, 
     xlab = substitute(paste("Here is ", pi, " = ", p), list(p = py)), 
     ylab = substitute(paste("e is = ", e ), list(e = ee)), 
     main = "Substituted Expressions")

Impose a line to a scatter plot

  • abline + lsfit # least squares
plot(cars)
abline(lsfit(cars[, 1], cars[, 2]))
# OR
abline(lm(cars[,2] ~ cars[,1]))
  • abline + line # robust line fitting
plot(cars)
(z <- line(cars))
abline(coef(z), col = 'green')
  • lines
plot(cars)
fit <- lm(cars[,2] ~ cars[,1])
lines(cars[,1], fitted(fit), col="blue")
lines(stats::lowess(cars), col='red')

How to actually make a quality scatterplot in R: axis(), mtext()

How to actually make a quality scatterplot in R

3D scatterplot

Rotating x axis labels for barplot

https://stackoverflow.com/questions/10286473/rotating-x-axis-labels-in-r-for-barplot

barplot(mytable,main="Car makes",ylab="Freqency",xlab="make",las=2)

Set R plots x axis to show at y=0

https://stackoverflow.com/questions/3422203/set-r-plots-x-axis-to-show-at-y-0

plot(1:10, rnorm(10), ylim=c(0,10), yaxs="i")

Different colors of axis labels in barplot

See Vary colors of axis labels in R based on another variable

Method 1: Append labels for the 2nd, 3rd, ... color gradually because 'col.axis' argument cannot accept more than one color.

tN <- table(Ni <- stats::rpois(100, lambda = 5))
r <- barplot(tN, col = rainbow(20))
axis(1, 1, LETTERS[1], col.axis="red", col="red")
axis(1, 2, LETTERS[2], col.axis="blue", col = "blue")

Method 2: text() which can accept multiple colors in 'col' parameter but we need to find out the (x, y) by ourselves.

barplot(tN, col = rainbow(20), axisnames = F)
text(4:6, par("usr")[3]-2 , LETTERS[4:6], col=c("black","red","blue"), xpd=TRUE)

Use text() to draw labels on X/Y-axis including rotation

par(mar = c(5, 6, 4, 5) + 0.1)
plot(..., xaxt = "n") # "n" suppresses plotting of the axis; need mtext() and axis() to supplement
text(x = barCenters, y = par("usr")[3] - 1, srt = 45,
     adj = 1, labels = myData$names, xpd = TRUE)

Vertically stacked plots with the same x axis

https://stackoverflow.com/questions/11794436/stacking-multiple-plots-vertically-with-the-same-x-axis-but-different-y-axes-in

Include labels on the top axis/margin: axis() and mtext()

plot(1:4, rnorm(4), axes = FALSE)
axis(3, at=1:4, labels = LETTERS[1:4], tick = FALSE, line = -0.5) # las, cex.axis
box()
mtext("Groups selected", cex = 0.8, line = 1.5) # default side = 3

See also 15_Questions_All_R_Users_Have_About_Plots

This can be used to annotate each plot with the script name, date, ...

mtext(text=paste("Prepared on", format(Sys.time(), "%d %B %Y at %H:%M")), 
      adj=.99,  # text align to right 
      cex=.75, side=3, las=1, line=2)

ggplot2 uses breaks instead of at parameter. See ggplot2 → Add axis on top or right hand side, ggplot2 → scale_x_continus(name, breaks, labels) and the scale_continuous documentation.

Legend tips

Add legend to a plot in R

Increase/decrease legend font size cex & ggplot2 package case.

plot(rnorm(100))
# op <- par(cex=2)
legend("topleft", legend = 1:4, col=1:4, pch=1, lwd=2, lty = 1, cex =2)
# par(op)

legend inset. Default is 0. % (from 0 to 1) to draw the legend away from x and y axis. The inset argument with negative values moves the legend outside the plot.

legend("bottomright", inset=.05, )

legend without a box

legend(, bty = "n")

Add a legend title

legend(, title = "")

Add a common legend to multiple plots. Use the layout function.

Superimpose a density plot or any curves

Use lines().

Example 1

plot(cars, main = "Stopping Distance versus Speed")
lines(stats::lowess(cars))

plot(density(x), col = "#6F69AC", lwd = 3)
lines(density(y), col = "#95DAC1", lwd = 3)
lines(density(z), col = "#FFEBA1", lwd = 3)

Example 2

require(survival)
n = 10000
beta1 = 2; beta2 = -1
lambdaT = 1 # baseline hazard
lambdaC = 2  # hazard of censoring
set.seed(1234)
x1 = rnorm(n,0)
x2 = rnorm(n,0)
# true event time
T = rweibull(n, shape=1, scale=lambdaT*exp(-beta1*x1-beta2*x2)) 
C <- rweibull(n, shape=1, scale=lambdaC)   
time = pmin(T,C)  
status <- 1*(T <= C) 
status2 <- 1-status
plot(survfit(Surv(time, status2) ~ 1), 
     ylab="Survival probability",
     main = 'Exponential censoring time')
xseq <- seq(.1, max(time), length =100)
func <- function(x) 1-pweibull(x, shape = 1, scale = lambdaC)
lines(xseq, func(xseq), col = 'red') # survival function of Weibull

Example 3. Use ggplot(df, aes(x = x, color = factor(grp))) + geom_density(). Then each density curve will represent data from each "grp".

log scale

If we set y-axis to use log-scale, then what we display is the value log(Y) or log10(Y) though we still label the values using the input. For example, when we plot c(1, 10, 100) using the log scale, it is like we draw log10(c(1, 10, 100)) = c(0,1,2) on the plot but label the axis using the true values c(1, 10, 100).

File:Logscale.png

Custom scales

Using custom scales with the 'scales' package

Time series

Time series stock price plot

library(quantmod)
getSymbols("AAPL")
getSymbols("IBM") # similar to AAPL
getSymbols("CSCO") # much smaller than AAPL, IBM
getSymbols("DJI") # Dow Jones, huge 
chart_Series(Cl(AAPL), TA="add_TA(Cl(IBM), col='blue', on=1); add_TA(Cl(CSCO), col = 'green', on=1)", 
    col='orange', subset = '2017::2017-08')

tail(Cl(DJI))

tidyquant: Getting stock data

The 'largest stock profit or loss' puzzle: efficient computation in R

Timeline plot

Clockify

Clockify

Circular plot

Word cloud

Text mining

World map

Visualising SSH attacks with R (rworldmap and rgeolocate packages)

Diagram/flowchart/Directed acyclic diagrams (DAGs)

DiagrammeR

diagram

Functions for Visualising Simple Graphs (Networks), Plotting Flow Diagrams

DAGitty (browser-based and R package)

dagR

Gmisc

Easiest flowcharts eveR?

Concept Maps

concept-maps where the diagrams are generated from https://app.diagrams.net/.

flow

flow, How To Draw Flow Diagrams In R

Venn Diagram

Venn diagram

hexbin plot

Bump chart/Metro map

https://dominikkoch.github.io/Bump-Chart/

Amazing/special plots

See Amazing plot.

Google Analytics

GAR package

http://www.analyticsforfun.com/2015/10/query-your-google-analytics-data-with.html

Linear Programming

http://www.r-bloggers.com/modeling-and-solving-linear-programming-with-r-free-book/

Linear Algebra

Amazon Alexa

R and Singularity

https://rviews.rstudio.com/2017/03/29/r-and-singularity/

Teach kids about R with Minecraft

http://blog.revolutionanalytics.com/2017/06/teach-kids-about-r-with-minecraft.html

Secure API keys

Securely store API keys in R scripts with the "secret" package

Credentials and secrets

How to manage credentials and secrets safely in R

Hide a password

keyring package

getPass

getPass

Vision and image recognition

Creating a Dataset from an Image

Creating a Dataset from an Image in R Markdown using reticulate

Turn pictures into coloring pages

https://gist.github.com/jeroen/53a5f721cf81de2acba82ea47d0b19d0

Numerical optimization

CRAN Task View: Numerical Mathematics, CRAN Task View: Optimization and Mathematical Programming

Ryacas: R Interface to the 'Yacas' Computer Algebra System

Doing Maths Symbolically: R as a Computer Algebra System (CAS)

Game

Music

  • gm. Require to install MuseScore, an open source and free notation software.

SAS

sasMap Static code analysis for SAS scripts

R packages

R packages

Tricks

Getting help

Better Coder/coding, best practices

E-notation

6.022E23 (or 6.022e23) is equivalent to 6.022×10^23

Getting user's home directory

See What are HOME and working directories?

# Windows
normalizePath("~")   # "C:\\Users\\brb\\Documents"
Sys.getenv("R_USER") # "C:/Users/brb/Documents"
Sys.getenv("HOME")   # "C:/Users/brb/Documents"

# Mac
normalizePath("~")   # [1] "/Users/brb"
Sys.getenv("R_USER") # [1] ""
Sys.getenv("HOME")   # "/Users/brb"

# Linux
normalizePath("~")   # [1] "/home/brb"
Sys.getenv("R_USER") # [1] ""
Sys.getenv("HOME")   # [1] "/home/brb"

tempdir()

  • The path is a per-session temporary directory. On parallel use, R processes forked by functions such as mclapply and makeForkCluster in package parallel share a per-session temporary directory.
  • Set temporary folder for R in Rstudio server

Distinguish Windows and Linux/Mac, R.Version()

identical(.Platform$OS.type, "unix") returns TRUE on Mac and Linux.

get_os <- function(){
  sysinf <- Sys.info()
  if (!is.null(sysinf)){
    os <- sysinf['sysname']
    if (os == 'Darwin')
      os <- "osx"
  } else { ## mystery machine
    os <- .Platform$OS.type
    if (grepl("^darwin", R.version$os))
      os <- "osx"
    if (grepl("linux-gnu", R.version$os))
      os <- "linux"
  }
  tolower(os)
}
names(R.Version())
#  [1] "platform"       "arch"           "os"             "system"        
#  [5] "status"         "major"          "minor"          "year"          
#  [9] "month"          "day"            "svn rev"        "language"      
# [13] "version.string" "nickname" 
getRversion()
# [1] ‘4.3.0’

Rprofile.site, Renviron.site (all platforms) and Rconsole (Windows only)

If we like to install R packages to a personal directory, follow this. Just add the line

R_LIBS_SITE=F:/R/library

to the file R_HOME/etc/x64/Renviron.site. In R, run Sys.getenv("R_LIBS_SITE") or Sys.getenv("R_LIBS_USER") to query the environment variable. See Environment Variables.

What is the best place to save Rconsole on Windows platform

Put/create the file <Rconsole> under C:/Users/USERNAME/Documents folder so no matter how R was upgraded/downgraded, it always find my preference.

My preferred settings:

  • Font: Consolas (it will be shown as "TT Consolas" in Rconsole)
  • Size: 12
  • background: black
  • normaltext: white
  • usertext: GreenYellow or orange (close to RStudio's Cobalt theme) or sienna1 or SpringGreen or tan1 or yellow

and others (default options)

  • pagebg: white
  • pagetext: navy
  • highlight: DarkRed
  • dataeditbg: white
  • dataedittext: navy (View() function)
  • dataedituser: red
  • editorbg: white (edit() function)
  • editortext: black

A copy of the Rconsole is saved in github.

How R starts up

https://rstats.wtf/r-startup.html

startup - Friendly R Startup Configuration

https://github.com/henrikbengtsson/startup

Saving and loading history automatically: .Rprofile & local()

  • savehistory("filename"). It will save everything from the beginning to the command savehistory() to a text file.
  • .Rprofile will automatically be loaded when R has started from that directory
  • Don't do things in your .Rprofile that affect how R code runs, such as loading a package like dplyr or ggplot or setting an option such as stringsAsFactors = FALSE. See Project-oriented workflow.
  • .Rprofile has been created/used by the packrat package to restore a packrat environment. See the packrat/init.R file and R packages → packrat.
  • Customizing Startup from R in Action, Fun with .Rprofile and customizing R startup
    • You can also place a .Rprofile file in any directory that you are going to run R from or in the user home directory.
    • At startup, R will source the Rprofile.site file. It will then look for a .Rprofile file to source in the current working directory. If it doesn't find it, it will look for one in the user's home directory.
    options(continue="  ") # default is "+ "
    options(prompt="R> ", continue=" ")
    options(editor="nano") # default is "vi" on Linux
    # options(htmlhelp=TRUE) 
    
    local({r <- getOption("repos")
          r["CRAN"] <- "https://cran.rstudio.com"
          options(repos=r)})
    
    .First <- function(){
     # library(tidyverse)
     cat("\nWelcome at", date(), "\n")
    }
    
    .Last <- function(){
     cat("\nGoodbye at ", date(), "\n")
    }  
    
  • https://stackoverflow.com/questions/16734937/saving-and-loading-history-automatically
  • The history file will always be read from the $HOME directory and the history file will be overwritten by a new session. These two problems can be solved if we define R_HISTFILE system variable.
  • local() function can be used in .Rprofile file to set up the environment even no new variables will be created (change repository, install packages, load libraries, source R files, run system() function, file/directory I/O, etc)

Linux or Mac

In ~/.profile or ~/.bashrc I put:

export R_HISTFILE=~/.Rhistory

In ~/.Rprofile I put:

if (interactive()) {
  if (.Platform$OS.type == "unix")  .First <- function() try(utils::loadhistory("~/.Rhistory")) 
  .Last <- function() try(savehistory(file.path(Sys.getenv("HOME"), ".Rhistory")))
}

Windows

If you launch R by clicking its icon from Windows Desktop, the R starts in C:\User\$USER\Documents directory. So we can create a new file .Rprofile in this directory.

if (interactive()) {
  .Last <- function() try(savehistory(file.path(Sys.getenv("HOME"), ".Rhistory")))
}

Disable "Save workspace image?" prompt when exit R?

How to disable "Save workspace image?" prompt in R?

R release versions

rversions: Query the main 'R' 'SVN' repository to find the released versions & dates.

getRversion()

getRversion()
[1] ‘4.3.0’

Detect number of running R instances in Windows

C:\Program Files\R>tasklist /FI "IMAGENAME eq Rscript.exe"
INFO: No tasks are running which match the specified criteria.

C:\Program Files\R>tasklist /FI "IMAGENAME eq Rgui.exe"

Image Name                     PID Session Name        Session#    Mem Usage
============================================================================
Rgui.exe                      1096 Console                    1     44,712 K

C:\Program Files\R>tasklist /FI "IMAGENAME eq Rserve.exe"

Image Name                     PID Session Name        Session#    Mem Usage
============================================================================
Rserve.exe                    6108 Console                    1    381,796 K

In R, we can use

> system('tasklist /FI "IMAGENAME eq Rgui.exe" ', intern = TRUE)
[1] ""                                                                            
[2] "Image Name                     PID Session Name        Session#    Mem Usage"
[3] "============================================================================"
[4] "Rgui.exe                      1096 Console                    1     44,804 K"

> length(system('tasklist /FI "IMAGENAME eq Rgui.exe" ', intern = TRUE))-3

Editor

http://en.wikipedia.org/wiki/R_(programming_language)#Editors_and_IDEs

  • Emacs + ESS. The ESS is useful in the case I want to tidy R code (the tidy_source() function in the formatR package sometimes gives errors; eg when I tested it on an R file like <GetComparisonResults.R> from BRB-ArrayTools v4.4 stable).
    • Edit the file C:\Program Files\GNU Emacs 23.2\site-lisp\site-start.el with something like
    (setq-default inferior-R-program-name
                  "c:/program files/r/r-2.15.2/bin/i386/rterm.exe")
    

GUI for Data Analysis

Update to Data Science Software Popularity 6/7/2023

BlueSky Statistics

Rcmdr

http://cran.r-project.org/web/packages/Rcmdr/index.html. After loading a dataset, click Statistics -> Fit models. Then select Linear regression, Linear model, GLM, Multinomial logit model, Ordinal regression model, Linear mixed model, and Generalized linear mixed model. However, Rcmdr does not include, e.g. random forest, SVM, glmnet, et al.

Deducer

http://cran.r-project.org/web/packages/Deducer/index.html

jamovi

Scope

See

source()

## foo.R ##
cat(ArrayTools, "\n")
## End of foo.R

# 1. Error
predict <- function() {
  ArrayTools <- "C:/Program Files" # or through load() function 
  source("foo.R")                  # or through a function call; foo()
}
predict()   # Object ArrayTools not found

# 2. OK. Make the variable global
predict <- function() {
  ArrayTools <<- "C:/Program Files'
  source("foo.R")
}
predict()  
ArrayTools

# 3. OK. Create a global variable
ArrayTools <- "C:/Program Files"
predict <- function() {
  source("foo.R")
}
predict()

Note that any ordinary assignments done within the function are local and temporary and are lost after exit from the function.

Example 1.

> ttt <- data.frame(type=letters[1:5], JpnTest=rep("999", 5), stringsAsFactors = F)
> ttt
  type JpnTest
1    a     999
2    b     999
3    c     999
4    d     999
5    e     999
> jpntest <- function() { ttt$JpnTest[1] ="N5"; print(ttt)}
> jpntest()
  type JpnTest
1    a      N5
2    b     999
3    c     999
4    d     999
5    e     999
> ttt
  type JpnTest
1    a     999
2    b     999
3    c     999
4    d     999
5    e     999

Example 2. How can we set global variables inside a function? The answer is to use the "<<-" operator or assign(, , envir = .GlobalEnv) function.

Other resource: Advanced R by Hadley Wickham.

Example 3. Writing functions in R, keeping scoping in mind

New environment

Run the same function on a bunch of R objects

mye = new.env()
load(<filename>, mye)
for(n in names(mye)) n = as_tibble(mye[[n]])

Just look at the contents of rda file without saving to anywhere (?load)

local({
   load("myfile.rda")
   ls()
})

Or use attach() which is a wrapper of load(). It creates an environment and slots it into the list right after the global environment, then populates it with the objects we're attaching.

attach("all.rda") # safer and will warn about masked objects w/ same name in .GlobalEnv
ls(pos = 2)
##  also typically need to cleanup the search path:
detach("file:all.rda")

If we want to read data from internet, load() works but not attach().

con <- url("http://some.where.net/R/data/example.rda")
## print the value to see what objects were created.
print(load(con))
close(con)
# Github example
# https://stackoverflow.com/a/62954840

source() case.

myEnv <- new.env()    
source("some_other_script.R", local=myEnv)
attach(myEnv, name="sourced_scripts")
search()
ls(2)
ls(myEnv)
with(myEnv, print(x))

str( , max) function

Use max.level parameter to avoid a long display of the structure of a complex R object. Use give.head = FALSE to hide the attributes. See ?str

If we use str() on a function like str(lm), it is equivalent to args(lm)

For a complicated list object, it is useful to use the max.level argument; e.g. str(, max.level = 1)

For a large data frame, we can use the tibble() function; e.g. mydf %>% tibble()

tidy() function

broom::tidy() provides a simplified form of an R object (obtained from running some analysis). See here.

View all objects present in a package, ls()

https://stackoverflow.com/a/30392688. In the case of an R package created by Rcpp.package.skeleton("mypackage"), we will get

> devtools::load_all("mypackage")
> search()
 [1] ".GlobalEnv"        "devtools_shims"    "package:mypackage"
 [4] "package:stats"     "package:graphics"  "package:grDevices"
 [7] "package:utils"     "package:datasets"  "package:methods"
[10] "Autoloads"         "package:base"

> ls("package:mypackage")
[1] "_mypackage_rcpp_hello_world" "evalCpp"                     "library.dynam.unload"       
[4] "rcpp_hello_world"            "system.file"

Note that the first argument of ls() (or detach()) is used to specify the environment. It can be

  • an integer (the position in the ‘search’ list);
  • the character string name of an element in the search list;
  • an explicit ‘environment’ (including using ‘sys.frame’ to access the currently active function calls).

Speedup R code

Profiler

&& vs &

See https://www.rdocumentation.org/packages/base/versions/3.5.1/topics/Logic.

  • The shorter form performs elementwise comparisons in much the same way as arithmetic operators. The return is a vector.
  • The longer form evaluates left to right examining only the first element of each vector. The return is one value.
  • The longer form evaluates left to right examining only the first element of each vector. Evaluation proceeds only until the result is determined.
  • The idea of the longer form && in R seems to be the same as the && operator in linux shell; see here.
  • Single or double?: AND operator and OR operator in R. The confusion might come from the inconsistency when choosing these operators in different languages. For example, in C, & performs bitwise AND, while && does Boolean logical AND.
  • Think of && as a stricter &
c(T,F,T) & c(T,T,T)
# [1]  TRUE FALSE  TRUE
c(T,F,T) && c(T,T,T)
# [1] TRUE
c(T,F,T) && c(F,T,T)
# [1] FALSE
c(T,F,T) && c(NA,T,T)
# [1] NA
# Assume 'b' is not defined
> if (TRUE && b==3) cat("end")
Error: object 'b' not found
> if (FALSE && b==3) cat("end")
> # No error since the 2nd condition is never evaluated

It's useful in functions(). We don't need nested if statements. In this case if 'arg' is missing, the argument 'L' is not needed so there is not syntax error.

> foo <- function(arg, L) {
   # Suppose 'L' is meaningful only if 'arg' is provided
   # 
   # Evaluate 'L' only if 'arg' is provided
   #
   if (!missing(arg) && L) {
     print("L is true")
   } else {
     print("Either arg is missing or L is FALSE")
   }
 }
> foo()
[1] "arg is missing or L is FALSE"
> foo("a", F)
[1] "arg is missing or L is FALSE"
> foo("a", T)
[1] "L is true"

Other examples: && is more flexible than &.

nspot <- ifelse(missing(rvm) || !rvm, nrow(exprTrain), sum(filter))

if (!is.null(exprTest) && any(is.na(exprTest))) { ... }

for-loop, control flow

Vectorization

sapply vs vectorization

Speed test: sapply vs vectorization

lapply vs for loop

split() and sapply()

split() can be used to split a vector, columns or rows. See How to split a data frame?

  • Split divides the data in the vector or data frame x into the groups defined by f. The syntax is
    split(x, f, drop = FALSE, …)
    
  • split() + cut(). How to Split Data into Equal Sized Groups in R: A Comprehensive Guide for Beginners
  • Split a vector into chunks. split() returns a vector/indices and the indices can be used in lapply() to subset the data. Useful for the split() + lapply() + do.call() or split() + sapply() operations.
    d <- 1:10
    chunksize <- 4
    ceiling(1:10/4)
    # [1] 1 1 1 1 2 2 2 2 3 3
    split(d, ceiling(seq_along(d)/chunksize))
    # $`1`
    # [1] 1 2 3 4
    #
    # $`2`
    # [1] 5 6 7 8
    #
    # $`3`
    # [1]  9 10
    do.call(c, lapply(split(d, ceiling(seq_along(d)/4)), function(x) sum(x)) ) 
    #  1  2  3 
    # 10 26 19
    
    # bigmemory vignette
    planeindices <- split(1:nrow(x), x[,'TailNum'])
    planeStart <- sapply(planeindices,
                         function(i) birthmonth(x[i, c('Year','Month'),
                                                drop=FALSE]))
    
  • Split rows of a data frame/matrix; e.g. rows represents genes. The data frame/matrix is split directly.
    split(mtcars,mtcars$cyl)
    
    split(data.frame(matrix(1:20, nr=10) ), ceiling(1:10/chunksize)) # data.frame/tibble works
    split.data.frame(matrix(1:20, nr=10), ceiling(1:10/chunksize))   # split.data.frame() works for matrices
    
  • Split columns of a data frame/matrix.
    ma <- cbind(x = 1:10, y = (-4:5)^2, z = 11:20)
    split(ma, cbind(rep(1,10), rep(2, 10), rep(1,10))) # not an interesting example
    # $`1`
    #  [1]  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20
    #
    # $`2`
    #  [1] 16  9  4  1  0  1  4  9 16 25
    
  • split() + sapply() to merge columns. See below Mean of duplicated columns for more detail.
  • split() + sapply() to split a vector. See nsFilter() function which can remove duplicated probesets/rows using unique Entrez Gene IDs (genefilter package). The source code of nsFilter() and findLargest().
    tSsp = split.default(testStat, lls) 
    # testStat is a vector of numerics including probeset IDs as names
    # lls is a vector of entrez IDs (same length as testStat)
    # tSSp is a list of the same length as unique elements of lls.
    
    sapply(tSsp, function(x) names(which.max(x))) 
    # return a vector of probset IDs of length of unique entrez IDs
    

strsplit and sapply

> namedf <- c("John ABC", "Mary CDE", "Kat FGH")
> strsplit(namedf, " ")
1
[1] "John" "ABC" 

2
[1] "Mary" "CDE" 

3
[1] "Kat" "FGH"

> sapply(strsplit(namedf, " "), "[", 1)
[1] "John" "Mary" "Kat" 
> sapply(strsplit(namedf, " "), "[", 2)
[1] "ABC" "CDE" "FGH"

Mean of duplicated columns: rowMeans; compute Means by each row

  • Reduce columns of a matrix by a function in R. To use rowMedians() instead of rowMeans(), we need to install matrixStats from CRAN.
    set.seed(1)
    x <- matrix(1:60, nr=10); x[1, 2:3] <- NA
    colnames(x) <- c("b", "b", "b", "c", "a", "a"); x
    res <- sapply(split(1:ncol(x), colnames(x)), 
                  function(i) rowMeans(x[, i, drop=F], na.rm = TRUE))
    res  # notice the sorting of columns
           a  b  c
     [1,] 46  1 31
     [2,] 47 12 32
     [3,] 48 13 33
     [4,] 49 14 34
     [5,] 50 15 35
     [6,] 51 16 36
     [7,] 52 17 37
     [8,] 53 18 38
     [9,] 54 19 39
    [10,] 55 20 40
    
    # vapply() is safter than sapply(). 
    # The 3rd arg in vapply() is a template of the return value.
    res2 <- vapply(split(1:ncol(x), colnames(x)), 
                   function(i) rowMeans(x[, i, drop=F], na.rm = TRUE),
                   rep(0, nrow(x)))
  • colSums, rowSums, colMeans, rowMeans (no group variable). These functions are equivalent to use of ‘apply’ with ‘FUN = mean’ or ‘FUN = sum’ with appropriate margins, but are a lot faster.
    rowMeans(x, na.rm=T)
    # [1] 31 27 28 29 30 31 32 33 34 35
    
    apply(x, 1, mean, na.rm=T)
    # [1] 31 27 28 29 30 31 32 33 34 35
    
  • matrixStats: Functions that Apply to Rows and Columns of Matrices (and to Vectors)
  • From for() loops to the split-apply-combine paradigm for column-wise tasks: the transition for a dinosaur

Mean of duplicated rows: colMeans and rowsum

  • colMeans(x, na.rm = FALSE, dims = 1), take mean per columns & sum over rows. It returns a vector. Other similar idea functions include colSums, rowSums, rowMeans.
    x <- matrix(1:60, nr=10); x[1, 2:3] <- NA; x
    rownames(x) <- c(rep("b", 2), rep("c", 3), rep("d", 4), "a") # move 'a' to the last
    res <- sapply(split(1:nrow(x), rownames(x)), 
                  function(i) colMeans(x[i, , drop=F], na.rm = TRUE))
    res <- t(res) # transpose is needed since sapply() will form the resulting matrix by columns
    res  # still a matrix, rows are ordered
    #   [,1] [,2] [,3] [,4] [,5] [,6]
    # a 10.0 20.0 30.0 40.0 50.0 60.0
    # b  1.5 12.0 22.0 31.5 41.5 51.5
    # c  4.0 14.0 24.0 34.0 44.0 54.0
    # d  7.5 17.5 27.5 37.5 47.5 57.5
    table(rownames(x))
    # a b c d
    # 1 2 3 4
    
    aggregate(x, list(rownames(x)), FUN=mean, na.rm = T) # EASY, but it becomes a data frame, rows are ordered
    #   Group.1   V1   V2   V3   V4   V5   V6
    # 1       a 10.0 20.0 30.0 40.0 50.0 60.0
    # 2       b  1.5 12.0 22.0 31.5 41.5 51.5
    # 3       c  4.0 14.0 24.0 34.0 44.0 54.0
    # 4       d  7.5 17.5 27.5 37.5 47.5 57.5
    
  • Reduce multiple probes by the maximally expressed probe (set) measured by average intensity across arrays
  • rowsum(x, group, reorder = TRUE, …). Sum over rows. It returns a matrix. This is very special. It's not the same as rowSums. There is no "colsum" function. It has the speed advantage over sapply+colSums OR aggregate.
    group <- rownames(x)
    rowsum(x, group, na.rm=T)/as.vector(table(group))
    #   [,1] [,2] [,3] [,4] [,5] [,6]
    # a 10.0 20.0 30.0 40.0 50.0 60.0
    # b  1.5  6.0 11.0 31.5 41.5 51.5
    # c  4.0 14.0 24.0 34.0 44.0 54.0
    # d  7.5 17.5 27.5 37.5 47.5 57.5
    
  • by() function. Calculating change from baseline in R
  • See aggregate Function in R- A powerful tool for data frames & summarize in r, Data Summarization In R
  • aggregate() function. Too slow! http://slowkow.com/2015/01/28/data-table-aggregate/. Don't use aggregate post.
    > attach(mtcars)
    dim(mtcars)
    [1] 32 11
    > head(mtcars)
                       mpg cyl disp  hp drat    wt  qsec vs am gear carb
    Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
    Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
    Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
    Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
    Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
    Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1
    > with(mtcars, table(cyl, vs))
       vs
    cyl  0  1
      4  1 10
      6  3  4
      8 14  0
    > aggdata <-aggregate(mtcars, by=list(cyl,vs),  FUN=mean, na.rm=TRUE)
    > print(aggdata)
      Group.1 Group.2      mpg cyl   disp       hp     drat       wt     qsec vs
    1       4       0 26.00000   4 120.30  91.0000 4.430000 2.140000 16.70000  0
    2       6       0 20.56667   6 155.00 131.6667 3.806667 2.755000 16.32667  0
    3       8       0 15.10000   8 353.10 209.2143 3.229286 3.999214 16.77214  0
    4       4       1 26.73000   4 103.62  81.8000 4.035000 2.300300 19.38100  1
    5       6       1 19.12500   6 204.55 115.2500 3.420000 3.388750 19.21500  1
             am     gear     carb
    1 1.0000000 5.000000 2.000000
    2 1.0000000 4.333333 4.666667
    3 0.1428571 3.285714 3.500000
    4 0.7000000 4.000000 1.500000
    5 0.0000000 3.500000 2.500000
    > detach(mtcars)
    
    # Another example: select rows with a minimum value from a certain column (yval in this case)
    > mydf <- read.table(header=T, text='
     id xval yval
     A 1  1
     A -2  2
     B 3  3
     B 4  4
     C 5  5
     ')
    > x = mydf$xval
    > y = mydf$yval
    > aggregate(mydf[, c(2,3)], by=list(id=mydf$id), FUN=function(x) x[which.min(y)])
      id xval yval
    1  A    1    1
    2  B    3    3
    3  C    5    5
    

Mean by Group

Mean by Group in R (2 Examples) | dplyr Package vs. Base R

aggregate(x = iris$Sepal.Length,                # Specify data column
          by = list(iris$Species),              # Specify group indicator
          FUN = mean)                           # Specify function (i.e. mean)
library(dplyr)
iris %>%                                        # Specify data frame
  group_by(Species) %>%                         # Specify group indicator
  summarise_at(vars(Sepal.Length),              # Specify column
               list(name = mean))               # Specify function
  • ave(x, ..., FUN),
  • aggregate(x, by, FUN),
  • by(x, INDICES, FUN): return is a list
  • tapply(): return results as a matrix or array. Useful for ragged array.

Apply family

Vectorize, aggregate, apply, by, eapply, lapply, mapply, rapply, replicate, scale, sapply, split, tapply, and vapply.

The following list gives a hierarchical relationship among these functions.

  • apply(X, MARGIN, FUN, ...) – Apply a Functions Over Array Margins
  • lapply(X, FUN, ...) – Apply a Function over a List (including a data frame) or Vector X.
    • sapply(X, FUN, ..., simplify = TRUE, USE.NAMES = TRUE) – Apply a Function over a List or Vector
      • replicate(n, expr, simplify = "array")
    • mapply(FUN, ..., MoreArgs = NULL, SIMPLIFY = TRUE, USE.NAMES = TRUE) – Multivariate version of sapply
      • Vectorize(FUN, vectorize.args = arg.names, SIMPLIFY = TRUE, USE.NAMES = TRUE) - Vectorize a Scalar Function
      • Map(FUN, ...) A wrapper to mapply with SIMPLIFY = FALSE, so it is guaranteed to return a list.
    • vapply(X, FUN, FUN.VALUE, ..., USE.NAMES = TRUE) – similar to sapply, but has a pre-specified type of return value
    • rapply(object, f, classes = "ANY", deflt = NULL, how = c("unlist", "replace", "list"), ...) – A recursive version of lapply
  • tapply(V, INDEX, FUN = NULL, ..., default = NA, simplify = TRUE) – Apply a Function Over a "Ragged" Array. V is typically a vector where split() will be applied. INDEX is a list of one or more factors.
    • aggregate(D, by, FUN, ..., simplify = TRUE, drop = TRUE) - Apply a function to each columns of subset data frame split by factors. FUN (such as mean(), weighted.mean(), sum()) is a simple function applied to a vector. D is typically a data frame. This is used to summarize data.
    • by(D, INDICES, FUN, ..., simplify = TRUE) - Apply a Function to each subset data frame split by factors. FUN (such as summary(), lm()) is applied to a data frame. D is typically a data frame.
  • eapply(env, FUN, ..., all.names = FALSE, USE.NAMES = TRUE) – Apply a Function over values in an environment

Difference between apply vs sapply vs lapply vs tapply?

  • apply - When you want to apply a function to the rows or columns or both of a matrix and output is a one-dimensional if only row or column is selected else it is a 2D-matrix
  • lapply - When you want to apply a function to each element of a list in turn and get a list back.
  • sapply - When you want to apply a function to each element of a list in turn, but you want a vector back, rather than a list.
  • tapply - When you want to apply a function to subsets of a vector and the subsets are defined by some other vector, usually a factor.

Some short examples:

Apply vs for loop

Note that, apply's performance is not always better than a for loop. See

Progress bar

What is the cost of a progress bar in R?

The package 'pbapply' creates a text-mode progress bar - it works on any platforms. On Windows platform, check out this post. It uses winProgressBar() and setWinProgressBar() functions.

e-Rum 2020 Slides on Progressr by Henrik Bengtsson. progressr 0.8.0: RStudio's progress bar, Shiny progress updates, and absolute progress, progressr 0.10.1: Plyr Now Supports Progress Updates also in Parallel

simplify option in sapply()

library(KEGGREST)

names1 <- keggGet(c("hsa05340", "hsa05410"))
names2 <- sapply(names1, function(x) x$GENE)
length(names2)  # same if we use lapply() above
# [1] 2

names3 <- keggGet(c("hsa05340"))
names4 <- sapply(names3, function(x) x$GENE)
length(names4)  # may or may not be what we expect
# [1] 76
names4 <- sapply(names3, function(x) x$GENE, simplify = FALSE)
length(names4)  # same if we use lapply() w/o simplify 
# [1] 1

lapply and its friends Map(), Reduce(), Filter() from the base package for manipulating lists

  • mapply() documentation. Use mapply() to merge lists.
    mapply(rep, 1:4, 4:1)
    mapply(rep, times = 1:4, x = 4:1)
    mapply(function(x, y) seq_len(x) + y,
           c(a =  1, b = 2, c = 3),  # names from first
           c(A = 10, B = 0, C = -10))
    mapply(c, firstList, secondList, SIMPLIFY=FALSE)
    
  • Finding the Expected value of the maximum of two Bivariate Normal variables with simulation sapply + mapply.
    z <- mapply(function(u, v) { max(u, v) }, 
                u = x[, 1], v = x[, 2])
    
  • Map() and Reduce() in functional programming
  • Map(), Reduce(), and Filter() from Advanced R by Hadley
    • If you have two or more lists (or data frames) that you need to process in parallel, use Map(). One good example is to compute the weighted.mean() function that requires two input objects. Map() is similar to mapply() function and is more concise than lapply(). Advanced R has a comment that Map() is better than mapply().
      # Syntax: Map(f, ...)
      
      xs <- replicate(5, runif(10), simplify = FALSE)
      ws <- replicate(5, rpois(10, 5) + 1, simplify = FALSE)
      Map(weighted.mean, xs, ws)
      
      # instead of a more clumsy way
      lapply(seq_along(xs), function(i) {
        weighted.mean(xsi, wsi)
      })
      
    • Reduce() reduces a vector, x, to a single value by recursively calling a function, f, two arguments at a time. A good example of using Reduce() function is to read a list of matrix files and merge them. See How to combine multiple matrix frames into one using R?
      # Syntax: Reduce(f, x, ...)
      
      > m1 <- data.frame(id=letters[1:4], val=1:4)
      > m2 <- data.frame(id=letters[2:6], val=2:6)
      > merge(m1, m2, "id", all = T)
        id val.x val.y
      1  a     1    NA
      2  b     2     2
      3  c     3     3
      4  d     4     4
      5  e    NA     5
      6  f    NA     6
      > m <- list(m1, m2)
      > Reduce(function(x,y) merge(x,y, "id",all=T), m)
        id val.x val.y
      1  a     1    NA
      2  b     2     2
      3  c     3     3
      4  d     4     4
      5  e    NA     5
      6  f    NA     6
      

sapply & vapply

See parallel::parSapply() for a parallel version of sapply(1:n, function(x)). We can this technique to speed up this example.

rapply - recursive version of lapply

replicate

https://www.datacamp.com/community/tutorials/tutorial-on-loops-in-r

> replicate(5, rnorm(3))
           [,1]       [,2]       [,3]      [,4]        [,5]
[1,]  0.2509130 -0.3526600 -0.3170790  1.064816 -0.53708856
[2,]  0.5222548  1.5343319  0.6120194 -1.811913 -1.09352459
[3,] -1.9905533 -0.8902026 -0.5489822  1.308273  0.08773477

See parSapply() for a parallel version of replicate().

Vectorize

> rep(1:4, 4:1)
 [1] 1 1 1 1 2 2 2 3 3 4
> vrep <- Vectorize(rep.int)
> vrep(1:4, 4:1)
1
[1] 1 1 1 1

2
[1] 2 2 2

3
[1] 3 3

4
[1] 4
> rweibull(1, 1, c(1, 2)) # no error but not sure what it gives?
[1] 2.17123
> Vectorize("rweibull")(n=1, shape = 1, scale = c(1, 2)) 
[1] 1.6491761 0.9610109
myfunc <- function(a, b) a*b
myfunc(1, 2) # 2
myfunc(3, 5) # 15
myfunc(c(1,3), c(2,5)) # 2 15
Vectorize(myfunc)(c(1,3), c(2,5)) # 2 15

myfunc2 <- function(a, b) if (length(a) == 1) a * b else NA
myfunc2(1, 2) # 2 
myfunc2(3, 5) # 15
myfunc2(c(1,3), c(2,5)) # NA
Vectorize(myfunc2)(c(1, 3), c(2, 5)) # 2 15
Vectorize(myfunc2)(c(1, 3, 6), c(2, 5)) # 2 15 12
                                        # parameter will be re-used

plyr and dplyr packages

Practical Data Science for Stats - a PeerJ Collection

The Split-Apply-Combine Strategy for Data Analysis (plyr package) in J. Stat Software.

A quick introduction to plyr with a summary of apply functions in R and compare them with functions in plyr package.

  1. plyr has a common syntax -- easier to remember
  2. plyr requires less code since it takes care of the input and output format
  3. plyr can easily be run in parallel -- faster

Tutorials

Examples of using dplyr:

tibble

Tidy DataFrames but not Tibbles

Tibble objects

  • it does not have row names (cf data frame),
  • it never changes the type of the inputs (e.g. it never converts strings to factors!),
  • it never changes the names of variables

To show all rows or columns of a tibble object,

print(tbObj, n= Inf)

print(tbObj, width = Inf)

If we try to do a match on some column of a tibble object, we will get zero matches. The issue is we cannot use an index to get a tibble column.

Subsetting: to extract a column from a tibble object, use [[ or $ or dplyr::pull(). Select Data Frame Columns in R.

TibbleObject$VarName
# OR
TibbleObject"VarName"
# OR
pull(TibbleObject, VarName) # won't be a tibble object anymore

# For multiple columns, use select()
dplyr::select(TibbleObject, -c(VarName1, VarName2)) # still a tibble object
# OR
dplyr::select(TibbleObject, 2:5) # 

Convert a data frame to a tibble See Tibble Data Format in R: Best and Modern Way to Work with Your Data

my_data <- as_tibble(iris)
class(my_data)

llply()

llply is equivalent to lapply except that it will preserve labels and can display a progress bar. This is handy if we want to do a crazy thing.

LLID2GOIDs <- lapply(rLLID, function(x) get("org.Hs.egGO")[[x]])

where rLLID is a list of entrez ID. For example,

get("org.Hs.egGO")[["6772"]]

returns a list of 49 GOs.

ddply()

http://lamages.blogspot.com/2012/06/transforming-subsets-of-data-in-r-with.html

ldply()

An R Script to Automatically download PubMed Citation Counts By Year of Publication

Performance/speed comparison

Performance comparison of converting list to data.frame with R language

Using R's set.seed() to set seeds for use in C/C++ (including Rcpp)

http://rorynolan.rbind.io/2018/09/30/rcsetseed/

get_seed()

See the same blog

get_seed <- function() {
  sample.int(.Machine$integer.max, 1)
}

Note: .Machine$integer.max = 2147483647 = 2^31 - 1.

Random seeds

By default, R uses the exact time in milliseconds of the computer's clock when R starts up to generate a seed. See ?Random.

set.seed(as.numeric(Sys.time()))

set.seed(as.numeric(Sys.Date()))  # same seed for each day

.Machine and the largest integer, double

See ?.Machine.

                          Linux/Mac  32-bit Windows 64-bit Windows
double.eps              2.220446e-16   2.220446e-16   2.220446e-16
double.neg.eps          1.110223e-16   1.110223e-16   1.110223e-16
double.xmin            2.225074e-308  2.225074e-308  2.225074e-308
double.xmax            1.797693e+308  1.797693e+308  1.797693e+308
double.base             2.000000e+00   2.000000e+00   2.000000e+00
double.digits           5.300000e+01   5.300000e+01   5.300000e+01
double.rounding         5.000000e+00   5.000000e+00   5.000000e+00
double.guard            0.000000e+00   0.000000e+00   0.000000e+00
double.ulp.digits      -5.200000e+01  -5.200000e+01  -5.200000e+01
double.neg.ulp.digits  -5.300000e+01  -5.300000e+01  -5.300000e+01
double.exponent         1.100000e+01   1.100000e+01   1.100000e+01
double.min.exp         -1.022000e+03  -1.022000e+03  -1.022000e+03
double.max.exp          1.024000e+03   1.024000e+03   1.024000e+03
integer.max             2.147484e+09   2.147484e+09   2.147484e+09
sizeof.long             8.000000e+00   4.000000e+00   4.000000e+00
sizeof.longlong         8.000000e+00   8.000000e+00   8.000000e+00
sizeof.longdouble       1.600000e+01   1.200000e+01   1.600000e+01
sizeof.pointer          8.000000e+00   4.000000e+00   8.000000e+00

NA when overflow

tmp <- 156287L
tmp*tmp
# [1] NA
# Warning message:
# In tmp * tmp : NAs produced by integer overflow
.Machine$integer.max
# [1] 2147483647

How to select a seed for simulation or randomization

set.seed() allow alphanumeric seeds

https://stackoverflow.com/a/10913336

set.seed(), for loop and saving random seeds

  • Detect When the Random Number Generator Was Used
    if (interactive()) {
      invisible(addTaskCallback(local({
        last <- .GlobalEnv$.Random.seed
        
        function(...) {
          curr <- .GlobalEnv$.Random.seed
          if (!identical(curr, last)) {
            msg <- "NOTE: .Random.seed changed"
            if (requireNamespace("crayon", quietly=TRUE)) msg <- crayon::blurred(msg)
            message(msg)
            last <<- curr
          }
          TRUE
        }
      }), name = "RNG tracker"))
    }
    
  • http://r.789695.n4.nabble.com/set-seed-and-for-loop-td3585857.html. This question is legitimate when we want to debug on a certain iteration.
    set.seed(1001) 
    data <- vector("list", 30) 
    seeds <- vector("list", 30) 
    for(i in 1:30) { 
      seeds[[i]] <- .Random.seed 
      data[[i]] <- runif(5) 
    } 
     
    # If we save and load .Random.seed from a file using scan(), make
    # sure to convert its type from doubles to integers.
    # Otherwise, .Random.seed will complain!
    
    .Random.seed <- seeds[[23]]  # restore 
    data.23 <- runif(5) 
    data.23 
    data[[23]] 
    
  • impute.knn
  • Duncan Murdoch: This works in this example, but wouldn't work with all RNGs, because some of them save state outside of .Random.seed. See ?.Random.seed for details.
  • Uwe Ligges's comment: set.seed() actually generates a seed. See ?set.seed that points us to .Random.seed (and relevant references!) which contains the actual current seed.
  • Petr Savicky's comment is also useful in the situation when it is not difficult to re-generate the data.
  • Local randomness in R.

sample()

sample() inaccurate on very large populations, fixed in R 3.6.0

# R 3.5.3
set.seed(123)
m <- (2/5)*2^32
m > 2^31
# [1] FALSE
log10(m)
# [1] 9.23502
x <- sample(m, 1000000, replace = TRUE)
table(x %% 2)
#      0      1 
# 400070 599930 
# R 3.5.3
# docker run --net=host -it --rm r-base:3.5.3
> set.seed(1234)
> sample(5)
[1] 1 3 2 4 5

# R 3.6.0
# docker run --net=host -it --rm r-base:3.6.0
> set.seed(1234)
> sample(5)
[1] 4 5 2 3 1
> RNGkind(sample.kind = "Rounding")
Warning message:
In RNGkind(sample.kind = "Rounding") : non-uniform 'Rounding' sampler used
> set.seed(1234)
> sample(5)
[1] 1 3 2 4 5

Getting different results with set.seed() in RStudio

Getting different results with set.seed(). It's possible that you're loading an R package that is changing the requested random number generator; RNGkind().

dplyr::sample_n()

The function has a parameter weight. For example if we have some download statistics for each day and we want to do sampling based on their download numbers, we can use this function.

Regular Expression

See here.

Read rrd file

on.exit()

Examples of using on.exit(). In all these examples, add = TRUE is used in the on.exit() call to ensure that each exit action is added to the list of actions to be performed when the function exits, rather than replacing the previous actions.

  • Database connections
    library(RSQLite)
    sqlite_get_query <- function(db, sql) {
      conn <- dbConnect(RSQLite::SQLite(), db)
      on.exit(dbDisconnect(conn), add = TRUE)
      dbGetQuery(conn, sql)
    }
    
  • File connections
    read_chars <- function(file_name) {
      conn <- file(file_name, "r")
      on.exit(close(conn), add = TRUE)
      readChar(conn, file.info(file_name)$size)
    }
    
  • Temporary files
    history_lines <- function() {
      f <- tempfile()
      on.exit(unlink(f), add = TRUE)
      savehistory(f)
      readLines(f, encoding = "UTF-8")
    }
    
  • Printing messages
    myfun = function(x) {
      on.exit(print("first"))
      on.exit(print("second"), add = TRUE)
      return(x)
    }
    

file, connection

  • cat() and scan() (read data into a vector or list from the console or file)
  • read() and write()
  • read.table() and write.table()
out = file('tmp.txt', 'w')
writeLines("abcd", out)
writeLines("eeeeee", out)
close(out)
readLines('tmp.txt')
unlink('tmp.txt')
args(writeLines)
# function (text, con = stdout(), sep = "\n", useBytes = FALSE)

foo <- function() {
  con <- file()
  ...
  on.exit(close(con))
  ...
}

Error in close.connection(f) : invalid connection. If we want to use close(con), we have to specify how to open the connection; such as

con <- gzfile(FileName, "r") # Or gzfile(FileName, open = 'r')
x <- read.delim(con)
close(x)

withr package

https://cran.r-project.org/web/packages/withr/index.html . Reverse suggested by languageserver.

Clipboard (?connections), textConnection(), pipe()

  • On Windows, we can use readClipboard() and writeClipboard().
    source("clipboard")
    read.table("clipboard")
    
  • Clipboard -> R. Reading/writing clipboard on macOS. Use textConnection() function:
    x <- read.delim(textConnection("<USE_KEYBOARD_TO_PASTE_FROM_CLIPBOARD>"))
    # Or on Mac
    x <- read.delim(pipe("pbpaste"))
    # safely ignore the warning: incomplete final line found by readTableHeader on 'pbpaste'
    

    An example is to copy data from this post. In this case we need to use read.table() instead of read.delim().

  • R -> clipboard on Mac. Note: pbcopy and pbpaste are macOS terminal commands. See pbcopy & pbpaste: Manipulating the Clipboard from the Command Line.
    • pbcopy: takes standard input and places it in the clipboard buffer
    • pbpaste: takes data from the clipboard buffer and writes it to the standard output
    clip <- pipe("pbcopy", "w")
    write.table(apply(x, 1, mean), file = clip, row.names=F, col.names=F)
    # write.table(data.frame(Var1, Var2), file = clip, row.names=F, quote=F, sep="\t")
    close(clip)
    
  • Clipboard -> Excel.
    • Method 1: Paste icon -> Text import wizard -> Delimit (Tab, uncheck Space) or Fixed width depending on the situation -> Finish.
    • Method 2: Ctrl+v first. Then choose Data -> Text to Columns. Fixed width -> Next -> Next -> Finish.
  • On Linux, we need to install "xclip". See R Copy from Clipboard in Ubuntu Linux. It seems to work.
    # sudo apt-get install xclip
    read.table(pipe("xclip -selection clipboard -o",open="r"))
    

clipr

clipr: Read and Write from the System Clipboard

read/manipulate binary data

  • x <- readBin(fn, raw(), file.info(fn)$size)
  • rawToChar(x[1:16])
  • See Biostrings C API

String Manipulation

format(): padding with zero

ngenes <- 10
genenames <- paste0("bm", gsub(" ", "0", format(1:ngenes))); genenames
#  [1] "bm01" "bm02" "bm03" "bm04" "bm05" "bm06" "bm07" "bm08" "bm09" "bm10"

noquote()

noqute Print character strings without quotes.

stringr package

glue package

  • glue. Useful in a loop and some function like ggtitle() or ggsave(). Inside the curly braces {R-Expression}, the expression is evaluated.
    library(glue)
    name <- "John"
    age <- 30
    glue("My name is {name} and I am {age} years old.")
    # My name is John and I am 30 years old.
    
    price <- 9.99
    quantity <- 3
    total <- glue("The total cost is {round(price * quantity, 2)}.")
    # Inside the curly braces {}, the expression round(price * quantity, 2) is evaluated.
    print(total)
    # The total cost is 29.97.

    The syntax of glue() in R is quite similar to Python's print() function when using formatted strings. In Python, you typically use f-strings to embed variables inside strings.

    name = "John"
    age = 30
    print(f"My name is {name} and I am {age} years old.")
    # My name is John and I am 30 years old.
    
    price = 9.99
    quantity = 3
    total = f"The total cost is {price * quantity:.2f}."
    print(total)
    # The total cost is 29.97.
  • String interpolation

Raw data type

Fun with strings, Cyrillic alphabets

a1 <- "А"
a2 <- "A"
a1 == a2
# [1] FALSE
charToRaw("А")
# [1] d0 90
charToRaw("A")
# [1] 41

number of characters limit

It's a limit on a (single) input line in the REPL

Comparing strings to numeric

">" coerces the number to a string before comparing. "10" < 2 # TRUE

HTTPs connection

HTTPS connection becomes default in R 3.2.2. See

R 3.3.2 patched The internal methods of ‘download.file()’ and ‘url()’ now report if they are unable to follow the redirection of a ‘http://’ URL to a ‘https://’ URL (rather than failing silently)

setInternet2

There was a bug in ftp downloading in R 3.2.2 (r69053) Windows though it is fixed now in R 3.2 patch.

Read the discussion reported on 8/8/2015. The error only happened on ftp not http connection. The final solution is explained in this post. The following demonstrated the original problem.

url <- paste0("ftp://ftp.ncbi.nlm.nih.gov/genomes/ASSEMBLY_REPORTS/All/",
              "GCF_000001405.13.assembly.txt")
f1 <- tempfile()
download.file(url, f1)

It seems the bug was fixed in R 3.2-branch. See 8/16/2015 patch r69089 where a new argument INTERNET_FLAG_PASSIVE was added to InternetOpenUrl() function of wininet library. This article and this post explain differences of active and passive FTP.

The following R command will show the exact svn revision for the R you are currently using.

R.Version()$"svn rev"

If setInternet2(T), then https protocol is supported in download.file().

When setInternet(T) is enabled by default, download.file() does not work for ftp protocol (this is used in getGEO() function of the GEOquery package). If I use setInternet(F), download.file() works again for ftp protocol.

The setInternet2() function is defined in R> src> library> utils > R > windows > sysutils.R.

R up to 3.2.2

setInternet2 <- function(use = TRUE) .Internal(useInternet2(use))

See also

  • <src/include/Internal.h> (declare do_setInternet2()),
  • <src/main/names.c> (show do_setInternet2() in C)
  • <src/main/internet.c> (define do_setInternet2() in C).

Note that: setInternet2(T) becomes default in R 3.2.2. To revert to the previous default use setInternet2(FALSE). See the <doc/NEWS.pdf> file. If we use setInternet2(F), then it solves the bug of getGEO() error. But it disables the https file download using the download.file() function. In R < 3.2.2, it is also possible to download from https by setIneternet2(T).

R 3.3.0

setInternet2 <- function(use = TRUE) {
    if(!is.na(use)) stop("use != NA is defunct")
    NA
}

Note that setInternet2.Rd says As from \R 3.3.0 it changes nothing, and only \code{use = NA} is accepted. Also NEWS.Rd says setInternet2() has no effect and will be removed in due course.

Finite, Infinite and NaN Numbers: is.finite(), is.infinite(), is.nan()

In R, basically all mathematical functions (including basic Arithmetic), are supposed to work properly with +/-, Inf and NaN as input or output.

See ?is.finite.

How to replace Inf with NA in All or Specific Columns of the Data Frame

replace() function

File/path operations

  • list.files(, include.dirs =F, recursive = T, pattern = "\\.csv$", all.files = TRUE)
  • file.info()
  • dir.create()
  • file.create()
  • file.copy()
  • file.exists()
  • basename() - remove the parent path, dirname() - returns the part of the path up to but excluding the last path separator
    > file.path("~", "Downloads")
    [1] "~/Downloads"
    > dirname(file.path("~", "Downloads"))
    [1] "/home/brb"
    > basename(file.path("~", "Downloads"))
    [1] "Downloads"
    
  • path.expand("~/.Renviron") # "/home/brb/.Renviron"
  • normalizePath() # Express File Paths in Canonical Form
    > cat(normalizePath(c(R.home(), tempdir())), sep = "\n")
    /usr/lib/R
    /tmp/RtmpzvDhAe
    
  • system.file() - Finds the full file names of files in packages etc
    > system.file("extdata", "ex1.bam", package="Rsamtools")
    [1] "/home/brb/R/x86_64-pc-linux-gnu-library/4.0/Rsamtools/extdata/ex1.bam"
    

read/download/source a file from internet

Simple text file http

retail <- read.csv("http://robjhyndman.com/data/ausretail.csv",header=FALSE)

Zip, RData, gz file and url() function

x <- read.delim(gzfile("filename.txt.gz"), nrows=10)
con = gzcon(url('http://www.systematicportfolio.com/sit.gz', 'rb'))
source(con)
close(con)

Here url() function is like file(), gzfile(), bzfile(), xzfile(), unz(), pipe(), fifo(), socketConnection(). They are used to create connections. By default, the connection is not opened (except for ‘socketConnection’), but may be opened by setting a non-empty value of argument ‘open’. See ?url.

Another example is Read gzipped csv directly from a url in R

con <- gzcon(url(paste("http://dumps.wikimedia.org/other/articlefeedback/",
                       "aa_combined-20110321.csv.gz", sep="")))
txt <- readLines(con)
dat <- read.csv(textConnection(txt))

Another example of using url() is

load(url("http:/www.example.com/example.RData"))

This does not work with load(), dget(), read.table() for files on OneDrive. In fact, I cannot use wget with shared files from OneDrive. The following trick works: How to configure a OneDrive file for use with wget.

Dropbox is easy and works for load(), wget, ...

R download .RData or Directly loading .RData from github from Github.

zip function

This will include 'hallmarkFiles' root folder in the files inside zip.

zip(zipfile = 'myFile.zip', 
    files = dir('hallmarkFiles', full.names = TRUE))

# Verify/view the files. 'list = TRUE' won't extract 
unzip('testZip.zip', list = TRUE) 

downloader package

This package provides a wrapper for the download.file function, making it possible to download files over https on Windows, Mac OS X, and other Unix-like platforms. The RCurl package provides this functionality (and much more) but can be difficult to install because it must be compiled with external dependencies. This package has no external dependencies, so it is much easier to install.

Google drive file based on https using RCurl package

require(RCurl)
myCsv <- getURL("https://docs.google.com/spreadsheet/pub?hl=en_US&hl=en_US&key=0AkuuKBh0jM2TdGppUFFxcEdoUklCQlJhM2kweGpoUUE&single=true&gid=0&output=csv")
read.csv(textConnection(myCsv))

Google sheet file using googlesheets package

Reading data from google sheets into R

Github files https using RCurl package

x = getURL("https://gist.github.com/arraytools/6671098/raw/c4cb0ca6fe78054da8dbe253a05f7046270d5693/GeneIDs.txt", 
            ssl.verifypeer = FALSE)
read.table(text=x)

data summary table

summarytools: create summary tables for vectors and data frames

https://github.com/dcomtois/summarytools. R Package for quickly and neatly summarizing vectors and data frames.

skimr: A frictionless, pipeable approach to dealing with summary statistics

skimr for useful and tidy summary statistics

modelsummary

modelsummary: Summary Tables and Plots for Statistical Models and Data: Beautiful, Customizable, and Publication-Ready

broom

Tidyverse->broom

Create publication tables using tables package

See p13 for example at here

R's tables packages is the best solution. For example,

> library(tables)
> tabular( (Species + 1) ~ (n=1) + Format(digits=2)*
+          (Sepal.Length + Sepal.Width)*(mean + sd), data=iris )
                                                  
                Sepal.Length      Sepal.Width     
 Species    n   mean         sd   mean        sd  
 setosa      50 5.01         0.35 3.43        0.38
 versicolor  50 5.94         0.52 2.77        0.31
 virginica   50 6.59         0.64 2.97        0.32
 All        150 5.84         0.83 3.06        0.44
> str(iris)
'data.frame':   150 obs. of  5 variables:
 $ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
 $ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
 $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
 $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
 $ Species     : Factor w/ 3 levels "setosa","versicolor",..: 1 1 1 1 1 1 1 1 1 1 ...

and

# This example shows some of the less common options         
> Sex <- factor(sample(c("Male", "Female"), 100, rep=TRUE))
> Status <- factor(sample(c("low", "medium", "high"), 100, rep=TRUE))
> z <- rnorm(100)+5
> fmt <- function(x) {
  s <- format(x, digits=2)
  even <- ((1:length(s)) %% 2) == 0
  s[even] <- sprintf("(%s)", s[even])
  s
}
> tabular( Justify(c)*Heading()*z*Sex*Heading(Statistic)*Format(fmt())*(mean+sd) ~ Status )
                  Status              
 Sex    Statistic high   low    medium
 Female mean       4.88   4.96   5.17 
        sd        (1.20) (0.82) (1.35)
 Male   mean       4.45   4.31   5.05 
        sd        (1.01) (0.93) (0.75)

fgsea example

vignette & source code

(archived) ClinReport: Statistical Reporting in Clinical Trials

https://cran.r-project.org/web/packages/ClinReport/index.html

Append figures to PDF files

How to append a plot to an existing pdf file. Hint: use the recordPlot() function.

Save base graphics as pseudo-objects

Save base graphics as pseudo-objects in R. Note there are some cons with this approach.

pdf(NULL)
dev.control(displaylist="enable")
plot(df$x, df$y)
text(40, 0, "Random")
text(60, 2, "Text")
lines(stats::lowess(df$x, df$y))
p1.base <- recordPlot()
invisible(dev.off())

# Display the saved plot
grid::grid.newpage()
p1.base

Extracting tables from PDFs

Print tables

addmargins()

tableone

Some examples

Cox models

finalfit package

table1

gtsummary

gt*

dplyr

https://stackoverflow.com/a/34587522. The output includes counts and proportions in a publication like fashion.

tables::tabular()

gmodels::CrossTable()

https://www.statmethods.net/stats/frequencies.html

base::prop.table(x, margin)

New function ‘proportions()’ and ‘marginSums()’. These should replace the unfortunately named ‘prop.table()’ and ‘margin.table()’. for R 4.0.0.

R> m <- matrix(1:4, 2)
R> prop.table(m, 1) # row percentage
          [,1]      [,2]
[1,] 0.2500000 0.7500000
[2,] 0.3333333 0.6666667
R> prop.table(m, 2) # column percentage
          [,1]      [,2]
[1,] 0.3333333 0.4285714
[2,] 0.6666667 0.5714286

stats::xtabs()

stats::ftable()

> ftable(Titanic, row.vars = 1:3)
                   Survived  No Yes
Class Sex    Age                   
1st   Male   Child            0   5
             Adult          118  57
      Female Child            0   1
             Adult            4 140
2nd   Male   Child            0  11
             Adult          154  14
      Female Child            0  13
             Adult           13  80
3rd   Male   Child           35  13
             Adult          387  75
      Female Child           17  14
             Adult           89  76
Crew  Male   Child            0   0
             Adult          670 192
      Female Child            0   0
             Adult            3  20
> ftable(Titanic, row.vars = 1:2, col.vars = "Survived")
             Survived  No Yes
Class Sex                    
1st   Male            118  62
      Female            4 141
2nd   Male            154  25
      Female           13  93
3rd   Male            422  88
      Female          106  90
Crew  Male            670 192
      Female            3  20
> ftable(Titanic, row.vars = 2:1, col.vars = "Survived")
             Survived  No Yes
Sex    Class                 
Male   1st            118  62
       2nd            154  25
       3rd            422  88
       Crew           670 192
Female 1st              4 141
       2nd             13  93
       3rd            106  90
       Crew             3  20
> str(Titanic)
 table [1:4, 1:2, 1:2, 1:2] 0 0 35 0 0 0 17 0 118 154 ...
 - attr(*, "dimnames")=List of 4
  ..$ Class   : chr [1:4] "1st" "2nd" "3rd" "Crew"
  ..$ Sex     : chr [1:2] "Male" "Female"
  ..$ Age     : chr [1:2] "Child" "Adult"
  ..$ Survived: chr [1:2] "No" "Yes"
> x <- ftable(mtcars[c("cyl", "vs", "am", "gear")])
> x
          gear  3  4  5
cyl vs am              
4   0  0        0  0  0
       1        0  0  1
    1  0        1  2  0
       1        0  6  1
6   0  0        0  0  0
       1        0  2  1
    1  0        2  2  0
       1        0  0  0
8   0  0       12  0  0
       1        0  0  2
    1  0        0  0  0
       1        0  0  0
> ftable(x, row.vars = c(2, 4))
        cyl  4     6     8   
        am   0  1  0  1  0  1
vs gear                      
0  3         0  0  0  0 12  0
   4         0  0  0  2  0  0
   5         0  1  0  1  0  2
1  3         1  0  2  0  0  0
   4         2  6  2  0  0  0
   5         0  1  0  0  0  0
> 
> ## Start with expressions, use table()'s "dnn" to change labels
> ftable(mtcars$cyl, mtcars$vs, mtcars$am, mtcars$gear, row.vars = c(2, 4),
         dnn = c("Cylinders", "V/S", "Transmission", "Gears"))

          Cylinders     4     6     8   
          Transmission  0  1  0  1  0  1
V/S Gears                               
0   3                   0  0  0  0 12  0
    4                   0  0  0  2  0  0
    5                   0  1  0  1  0  2
1   3                   1  0  2  0  0  0
    4                   2  6  2  0  0  0
    5                   0  1  0  0  0  0

tracemem, data type, copy

How to avoid copying a long vector

Tell if the current R is running in 32-bit or 64-bit mode

8 * .Machine$sizeof.pointer

where sizeof.pointer returns the number of *bytes* in a C SEXP type and '8' means number of bits per byte.

32- and 64-bit

See R-admin.html.

  • For speed you may want to use a 32-bit build, but to handle large datasets a 64-bit build.
  • Even on 64-bit builds of R there are limits on the size of R objects, some of which stem from the use of 32-bit integers (especially in FORTRAN code). For example, the dimensionas of an array are limited to 2^31 -1.
  • Since R 2.15.0, it is possible to select '64-bit Files' from the standard installer even on a 32-bit version of Windows (2012/3/30).

Handling length 2^31 and more in R 3.0.0

From R News for 3.0.0 release:

There is a subtle change in behaviour for numeric index values 2^31 and larger. These never used to be legitimate and so were treated as NA, sometimes with a warning. They are now legal for long vectors so there is no longer a warning, and x[2^31] <- y will now extend the vector on a 64-bit platform and give an error on a 32-bit one.

In R 2.15.2, if I try to assign a vector of length 2^31, I will get an error

> x <- seq(1, 2^31)
Error in from:to : result would be too long a vector

However, for R 3.0.0 (tested on my 64-bit Ubuntu with 16GB RAM. The R was compiled by myself):

> system.time(x <- seq(1,2^31))
   user  system elapsed
  8.604  11.060 120.815
> length(x)
[1] 2147483648
> length(x)/2^20
[1] 2048
> gc()
             used    (Mb) gc trigger    (Mb)   max used    (Mb)
Ncells     183823     9.9     407500    21.8     350000    18.7
Vcells 2147764406 16386.2 2368247221 18068.3 2148247383 16389.9
>

Note:

  1. 2^31 length is about 2 Giga length. It takes about 16 GB (2^31*8/2^20 MB) memory.
  2. On Windows, it is almost impossible to work with 2^31 length of data if the memory is less than 16 GB because virtual disk on Windows does not work well. For example, when I tested on my 12 GB Windows 7, the whole Windows system freezes for several minutes before I force to power off the machine.
  3. My slide in http://goo.gl/g7sGX shows the screenshots of running the above command on my Ubuntu and RHEL machines. As you can see the linux is pretty good at handling large (> system RAM) data. That said, as long as your linux system is 64-bit, you can possibly work on large data without too much pain.
  4. For large dataset, it makes sense to use database or specially crafted packages like bigmemory or ff or bigstatsr.
  5. [[<- for index 2^31 fails

NA in index

  • Question: what is seq(1, 3)[c(1, 2, NA)]?

Answer: It will reserve the element with NA in indexing and return the value NA for it.

  • Question: What is TRUE & NA?

Answer: NA

  • Question: What is FALSE & NA?

Answer: FALSE

  • Question: c("A", "B", NA) != "" ?

Answer: TRUE TRUE NA

  • Question: which(c("A", "B", NA) != "") ?

Answer: 1 2

  • Question: c(1, 2, NA) != "" & !is.na(c(1, 2, NA)) ?

Answer: TRUE TRUE FALSE

  • Question: c("A", "B", NA) != "" & !is.na(c("A", "B", NA)) ?

Answer: TRUE TRUE FALSE

Conclusion: In order to exclude empty or NA for numerical or character data type, we can use which() or a convenience function keep.complete(x) <- function(x) x != "" & !is.na(x). This will guarantee return logical values and not contain NAs.

Don't just use x != "" OR !is.na(x).

Some functions

Constant and 'L'

Add 'L' after a constant. For example,

for(i in 1L:n) { }

if (max.lines > 0L) { }

label <- paste0(n-i+1L, ": ")

n <- length(x);  if(n == 0L) { }

Vector/Arrays

R indexes arrays from 1 like Fortran, not from 0 like C or Python.

remove integer(0)

How to remove integer(0) from a vector?

Append some elements

append() and its after argument

setNames()

Assign names to a vector

z <- setNames(1:3, c("a", "b", "c"))
# OR
z <- 1:3; names(z) <- c("a", "b", "c")
# OR
z <- c("a"=1, "b"=2, "c"=3) # not work if "a", "b", "c" is like x[1], x[2], x[3].

Factor

labels argument

We can specify the factor levels and new labels using the factor() function.

sex <- factor(sex, levels = c("0", "1"), labels = c("Male", "Female"))
drug_treatment <- factor(drug_treatment, levels = c("Placebo", "Low dose", "High dose"))
health_status <- factor(health_status, levels = c("Healthy", "Alzheimer's"))

factor(rev(letters[1:3]), labels = c("A", "B", "C"))
# C B A
# Levels: A B C

Create a factor/categorical variable from a continuous variable: cut() and dplyr::case_when()

cut(
     c(0, 10, 30), 
     breaks = c(0, 30, 50, Inf), 
     labels = c("Young", "Middle-aged", "Elderly")
 )  # Default include.lowest = FALSE
# [1] <NA>  Young Young
  • ?cut
    set.seed(1)
    x <- rnorm(100)
    facVar <- cut(x, c(min(x), -1, 1, max(x)), labels = c("low", "medium", "high"))
    table(facVar, useNA = "ifany")
    facVar
    #   low medium   high   <NA> 
    #    10     74     15      1 
    

    Note the option include.lowest = TRUE is needed when we use cut() + quantile(); otherwise the smallest data will become NA since the intervals have the format (a, b].

    x2 <- cut(x, quantile(x, 0:2/2), include.lowest = TRUE) # split x into 2 levels
    x2 <- cut(x, quantile(x, 0:3/3), include.lowest = TRUE) # split x into 3 levels
    
    library(tidyverse); library(magrittr)
    set.seed(1)
    breaks <- quantile(runif(100), probs=seq(0, 1, len=20))
    x <- runif(50)
    bins <- cut(x, breaks=unique(breaks), include.lowest=T, right=T)
    
    data.frame(sc=x, bins=bins) %>% 
      group_by(bins) %>% 
      summarise(n=n()) %>% 
      ggplot(aes(x = bins, y = n)) + 
        geom_col(color = "black", fill = "#90AACB") + 
        theme_minimal() + 
        theme(axis.text.x = element_text(angle = 90)) + 
        theme(legend.position = "none") + coord_flip()
    
  • A Guide to Using the cut() Function in R
  • tibble object
    library(tidyverse)
    tibble(age_yrs = c(0, 4, 10, 15, 24, 55),
           age_cat = case_when(
              age_yrs < 2 ~ "baby",
              age_yrs < 13 ~ "kid",
              age_yrs < 20 ~ "teen",
              TRUE         ~ "adult")
    )
    
  • R tip: Learn dplyr’s case_when() function
    case_when(
      condition1 ~ value1, 
      condition2 ~ value2,
      TRUE ~ ValueAnythingElse
    )
    # Example
    case_when(
      x %%2 == 0 ~ "even",
      x %%2 == 1 ~ "odd",
      TRUE ~ "Neither even or odd"
    )
    

How to change one of the level to NA

https://stackoverflow.com/a/25354985. Note that the factor level is removed.

x <- factor(c("a", "b", "c", "NotPerformed"))
levels(x)[levels(x) == 'NotPerformed'] <- NA

Creating missing values in factors

Concatenating two factor vectors

Not trivial. How to concatenate factors, without them being converted to integer level?.

unlist(list(f1, f2))
# unlist(list(factor(letters[1:5]), factor(letters[5:2])))

droplevels()

droplevels(): drop unused levels from a factor or, more commonly, from factors in a data frame.

factor(x , levels = ...) vs levels(x) <-

Note levels(x) is to set/rename levels, not reorder. Use relevel() or factor() to reorder.

levels()
plyr::revalue()
forcats::fct_recode()
rename levels
factor(, levels) reorder levels
sizes <- factor(c("small", "large", "large", "small", "medium"))
sizes
#> [1] small  large  large  small  medium
#> Levels: large medium small

sizes2 <- factor(sizes, levels = c("small", "medium", "large")) # reorder levels but data is not changed
sizes2
# [1] small  large  large  small  medium
# Levels: small medium large

sizes3 <- sizes
levels(sizes3) <- c("small", "medium", "large") # rename, not reorder
                                                # large -> small
                                                # medium -> medium
                                                # small -> large 
sizes3
# [1] large  small  small  large  medium
# Levels: small medium large

A regression example.

set.seed(1)
x <- sample(1:2, 500, replace = TRUE)
y <- round(x + rnorm(500), 3)
x <- as.factor(x)
sample_data <- data.frame(x, y)
 
# create linear model
summary(lm( y~x, sample_data))
# Coefficients:
#             Estimate Std. Error t value Pr(>|t|)    
# (Intercept)  0.96804    0.06610   14.65   <2e-16 ***
# x2           0.99620    0.09462   10.53   <2e-16 ***

# Wrong way when we want to change the baseline level to '2'
# No change on the model fitting except the apparent change on the variable name in the printout
levels(sample_data$x) <- c("2", "1")
summary(lm( y~x, sample_data))
# Coefficients:
#             Estimate Std. Error t value Pr(>|t|)    
# (Intercept)  0.96804    0.06610   14.65   <2e-16 ***
# x1           0.99620    0.09462   10.53   <2e-16 ***

# Correct way if we want to change the baseline level to '2'
# The estimate was changed by flipping the sign from the original data
sample_data$x <- relevel(x, ref = "2")
summary(lm( y~x, sample_data))
# Coefficients:
#             Estimate Std. Error t value Pr(>|t|)    
# (Intercept)  1.96425    0.06770   29.01   <2e-16 ***
# x1          -0.99620    0.09462  -10.53   <2e-16 ***

stats::relevel()

relevel. This function can only be used to change the reference level of a factor variable. It does not directly create an arbitrary order of levels. That is, it is useful in lm() or aov(), etc.

reorder(), levels() and boxplot()

  • How to Reorder Boxplots in R: A Comprehensive Guide (tapply() method, simple & effective)
  • reorder().This is useful in barplot (ggplot2::geom_col()) where we want to sort the bars by a numerical variable.
    # Syntax:
    # newFac <- with(df, reorder(fac, vec, FUN=mean)) # newFac is like fac except it has a new order
    
    (bymedian <- with(InsectSprays, reorder(spray, count, median)) )
    class(bymedian)
    levels(bymedian)
    boxplot(count ~ bymedian, data = InsectSprays,
            xlab = "Type of spray", ylab = "Insect count",
            main = "InsectSprays data", varwidth = TRUE,
            col = "lightgray") # boxplots are sorted according to the new levels
    boxplot(count ~ spray, data = InsectSprays,
            xlab = "Type of spray", ylab = "Insect count",
            main = "InsectSprays data", varwidth = TRUE,
            col = "lightgray") # not sorted
    
  • Statistics Sunday: My 2019 Reading (reorder function)

factor() vs ordered()

factor(levels=c("a", "b", "c"), ordered=TRUE)
# ordered(0)
# Levels: a < b < c

factor(levels=c("a", "b", "c"))
# factor(0)
# Levels: a b c

ordered(levels=c("a", "b", "c"))
# Error in factor(x, ..., ordered = TRUE) : 
#  argument "x" is missing, with no default

Data frame

stringsAsFactors = FALSE

http://www.win-vector.com/blog/2018/03/r-tip-use-stringsasfactors-false/

We can use options(stringsAsFactors=FALSE) forces R to import character data as character objects.

In R 4.0.0, stringAsFactors=FALSE will be default. This also affects read.table() function.

check.names = FALSE

Note this option will not affect rownames. So if the rownames contains special symbols, like dash, space, parentheses, etc, they will not be modified.

> data.frame("1a"=1:2, "2a"=1:2, check.names = FALSE)
  1a 2a
1  1  1
2  2  2
> data.frame("1a"=1:2, "2a"=1:2) # default
  X1a X2a
1   1   1
2   2   2

Create unique rownames: make.unique()

groupCodes <- c(rep("Cont",5), rep("Tre1",5), rep("Tre2",5))
rownames(mydf) <- make.unique(groupCodes)

data.frame() will change rownames

class(df2)
# [1] "matrix" "array"
rownames(df2)[c(9109, 44999)]
# [1] "A1CF"     "A1BG-AS1"
rownames(data.frame(df2))[c(9109, 44999)]
# [1] "A1CF"     "A1BG.AS1"

Print a data frame without rownames

# Method 1. 
rownames(df1) <- NULL

# Method 2. 
print(df1, row.names = FALSE)

Convert data frame factor columns to characters

Convert data.frame columns from factors to characters

# Method 1:
bob <- data.frame(lapply(bob, as.character), stringsAsFactors=FALSE)

# Method 2:
bob[] <- lapply(bob, as.character)

To replace only factor columns:

# Method 1:
i <- sapply(bob, is.factor)
bob[i] <- lapply(bob[i], as.character)

# Method 2:
library(dplyr)
bob %>% mutate_if(is.factor, as.character) -> bob

Sort Or Order A Data Frame

How To Sort Or Order A Data Frame In R

  1. df[order(df$x), ], df[order(df$x, decreasing = TRUE), ], df[order(df$x, df$y), ]
  2. library(plyr); arrange(df, x), arrange(df, desc(x)), arrange(df, x, y)
  3. library(dplyr); df %>% arrange(x),df %>% arrange(x, desc(x)), df %>% arrange(x, y)
  4. library(doBy); order(~x, df), order(~ -x, df), order(~ x+y, df)

data.frame to vector

df <- data.frame(x = c(1, 2, 3), y = c(4, 5, 6))

class(df)
# [1] "data.frame"
class(t(df))
# [1] "matrix" "array"
class(unlist(df))
# [1] "numeric"

# Method 1: Convert data frame to matrix using as.matrix()
# and then Convert matrix to vector using as.vector() or c()
mat <- as.matrix(df)
vec1 <- as.vector(mat)   # [1] 1 2 3 4 5 6
vec2 <- c(mat)

# Method 2: Convert data frame to matrix using t()/transpose
# and then Convert matrix to vector using as.vector() or c()
vec3 <- as.vector(t(df)) # [1] 1 4 2 5 3 6
vec4 <- c(t(df))

# Not working
as.vector(df)
# $x
# [1] 1 2 3
# $y
# [1] 4 5 6

# Method 3: unlist() - easiest solution
unlist(df)
# x1 x2 x3 y1 y2 y3 
#  1  2  3  4  5  6 
unlist(data.frame(df), use.names = F) # OR dplyr::pull()
# [1] 1 2 3 4 5 6

Q: Why as.vector(df) cannot convert a data frame into a vector?

A: The as.vector function cannot be used directly on a data frame to convert it into a vector because a data frame is a list of vectors (i.e., its columns) and as.vector only removes the attributes of an object to create a vector. When you apply as.vector to a data frame, R does not know how to concatenate these independent columns (which could be of different types) into a single vector. Therefore, it doesn’t perform the operation. Therefore as.vector() returns the underlying list structure of the data frame instead of converting it into a vector.

However, when you transpose the data frame using t(), it gets converted into a matrix. A matrix in R is a vector with dimensions. Therefore, all elements of the matrix must be of the same type. If they are not, R will coerce them to be so. Once you have a matrix, as.vector() can easily convert it into a vector because all elements are of the same type.

Using cbind() to merge vectors together?

It’s a common mistake to try and create a data frame by cbind()ing vectors together. This doesn’t work because cbind() will create a matrix unless one of the arguments is already a data frame. Instead use data.frame() directly. See Advanced R -> Data structures chapter.

cbind NULL and data.frame

cbind can't combine NULL with dataframe. Add as.matrix() will fix the problem.

merge

Special character in the matched variable can create a trouble when we use merge() or dplyr::inner_join(). I guess R internally turns df2 (a matrix but not a data frame) to a data frame (so rownames are changed if they contain special character like "-"). This still does not explain the situation when I

class(df1); class(df2)
# [1] "data.frame"  # 2 x 2
# [1] "matrix" "array" # 52439 x 2
rownames(df1)
# [1] "A1CF"     "A1BG-AS1"
merge(df1, df2[c(9109, 44999), ], by=0)
#   Row.names 786-0 A498 ACH-000001 ACH-000002
# 1  A1BG-AS1     0    0   7.321358   6.908333
# 2      A1CF     0    0   3.011470   1.189578
merge(df1, df2[c(9109, 38959:44999), ], by= 0) # still correct
merge(df1, df2[c(9109, 38958:44999), ], by= 0) # same as merge(df1, df2, by=0)
#   Row.names 786-0 A498 ACH-000001 ACH-000002
# 1      A1CF     0    0    3.01147   1.189578
rownames(df2)[38958:38959]
# [1] "ITFG2-AS1"  "ADGRD1-AS1"

rownames(df1)[2] <- "A1BGAS1"
rownames(df2)[44999] <- "A1BGAS1"
merge(df1, df2, by= 0)
#   Row.names 786-0 A498 ACH-000001 ACH-000002
# 1   A1BGAS1     0    0   7.321358   6.908333
# 2      A1CF     0    0   3.011470   1.189578

is.matrix: data.frame is not necessarily a matrix

See ?matrix. is.matrix returns TRUE if x is a vector and has a "dim" attribute of length 2 and FALSE otherwise.

An example that is a data frame (is.data.frame() returns TRUE) but not a matrix (is.matrix() returns FALSE) is an object returned by

X <- data.frame(x=1:2, y=3:4)

The 'X' object is NOT a vector and it does NOT have the "dim" attribute. It has only 3 attributes: "names", "row.names" & "class". Note that dim() function works fine and returns correctly though there is not "dim" attribute.

Another example that is a data frame but not a matrix is the built-in object cars; see ?matrix. It is not a vector

Convert a data frame to a matrix: as.matrix() vs data.matrix()

If I have a data frame X which recorded the time of some files.

  • is.data.frame(X) shows TRUE but is.matrix(X) show FALSE
  • as.matrix(X) will keep the time mode. The returned object is not a data frame anymore.
  • data.matrix(X) will convert the time to numerical values. So use data.matrix() if the data is numeric. The returned object is not a data frame anymore.
# latex directory contains cache files from knitting an rmarkdown file
X <- list.files("latex/", full.names = T) %>%
     grep("RData", ., value=T) %>% 
     file.info() %>%  
     `[`("mtime")
X %>% is.data.frame() # TRUE
X %>% is.matrix() # FALSE
X %>% as.matrix() %>% is.matrix() # TRUE
X %>% data.matrix() %>% is.matrix() # TRUE
X %>% as.matrix() %>% "["(1:2, ) # timestamps
X %>% data.matrix() %>% "["(1:2, ) # numeric
  • The as.matrix() function is used to coerce an object into a matrix. It can be used with various types of R objects, such as vectors, data frames, and arrays.
  • The data.matrix() function is specifically designed for converting a data frame into a matrix by coercing all columns to numeric values. If the data frame contains non-numeric columns, such as character or factor columns, data.matrix() will convert them to numeric values if possible (e.g., by converting factors to their integer codes).
  • See the following example where as.matrix() and data.matrix() return different resuls.
df <- data.frame(a = c(1, 2, 3), b = c("x", "y", "z"))
mat <- as.matrix(df)
mat
#      a   b  
# [1,] "1" "x"
# [2,] "2" "y"
# [3,] "3" "z"
class(mat)
# [1] "matrix" "array" 
mat2 <- data.matrix(df)
mat2
#      a b
# [1,] 1 1
# [2,] 2 2
# [3,] 3 3
class(mat2)
# [1] "matrix" "array" 
typeof(mat)
# [1] "character"
typeof(mat2)
# [1] "double"

matrix vs data.frame

Case 1: colnames() is safer than names() if the object could be a data frame or a matrix.

Browse[2]> names(res2$surv.data.new[[index]])
NULL
Browse[2]> colnames(res2$surv.data.new[[index]])
 [1] "time"   "status" "treat"  "AKT1"   "BRAF"   "FLOT2"  "MTOR"   "PCK2"   "PIK3CA"
[10] "RAF1"  
Browse[2]> mode(res2$surv.data.new[[index]])
[1] "numeric"
Browse[2]> is.matrix(res2$surv.data.new[[index]])
[1] TRUE
Browse[2]> dim(res2$surv.data.new[[index]])
[1] 991  10

Case 2:

ip1 <- installed.packages()[,c(1,3:4)] # class(ip1) = 'matrix'
unique(ip1$Priority)
# Error in ip1$Priority : $ operator is invalid for atomic vectors
unique(ip1[, "Priority"])   # OK

ip2 <- as.data.frame(installed.packages()[,c(1,3:4)], stringsAsFactors = FALSE) # matrix -> data.frame
unique(ip2$Priority)     # OK

The length of a matrix and a data frame is different.

> length(matrix(1:6, 3, 2))
[1] 6
> length(data.frame(matrix(1:6, 3, 2)))
[1] 2
> x[1]
  X1
1  1
2  2
3  3
4  4
5  5
6  6
> x1
[1] 1 2 3 4 5 6

So the length of a data frame is the number of columns. When we use sapply() function on a data frame, it will apply to each column of the data frame.

How to Remove Duplicates

How to Remove Duplicates in R with Example

Convert a matrix (not data frame) of characters to numeric

Just change the mode of the object

tmp <- cbind(a=c("0.12", "0.34"), b =c("0.567", "0.890")); tmp
     a     b
1 0.12 0.567
2 0.34 0.890
> is.data.frame(tmp) # FALSE
> is.matrix(tmp)     # TRUE
> sum(tmp)
Error in sum(tmp) : invalid 'type' (character) of argument
> mode(tmp)  # "character"

> mode(tmp) <- "numeric"
> sum(tmp)
[1] 1.917

Convert Data Frame Row to Vector

as.numeric() or c()

Convert characters to integers

mode(x) <- "integer"

Non-Standard Evaluation

Understanding Non-Standard Evaluation. Part 1: The Basics

Select Data Frame Columns in R

This is part of series of DATA MANIPULATION IN R from datanovia.com

  • pull(): Extract column values as a vector. The column of interest can be specified either by name or by index.
  • select(): Extract one or multiple columns as a data table. It can be also used to remove columns from the data frame.
  • select_if(): Select columns based on a particular condition. One can use this function to, for example, select columns if they are numeric.
  • Helper functions - starts_with(), ends_with(), contains(), matches(), one_of(): Select columns/variables based on their names

Another way is to the dollar sign $ operator (?"$") to extract rows or column from a data frame.

class(USArrests)  # "data.frame"
USArrests$"Assault"

Note that for both data frame and matrix objects, we need to use the [ operator to extract columns and/or rows.

USArrests[c("Alabama", "Alask"), c("Murder", "Assault")]
#         Murder Assault
# Alabama   13.2     236
# Alaska    10.0     263
USArrests[c("Murder", "Assault")]  # all rows

tmp <- data(package="datasets")
class(tmp$results)  # "matrix" "array" 
tmp$results[, "Item"]
# Same method can be used if rownames are available in a matrix

Note for a data.table object, we can extract columns using the column names without double quotes.

data.table(USArrests)[1:2, list(Murder, Assault)]

Add columns to a data frame

How to add columns to a data frame in R

Exclude/drop/remove data frame columns

# method 1
df = subset(mydata, select = -c(x,z) )

# method 2
drop <- c("x","z")
df = mydata[,!(names(mydata) %in% drop)]

# method 3: dplyr
mydata2 = select(mydata, -a, -x, -y)
mydata2 = select(mydata, -c(a, x, y))
mydata2 = select(mydata, -a:-y)
mydata2 = mydata[,!grepl("^INC",names(mydata))]

Remove Rows from the data frame

Remove Rows from the data frame in R

Danger of selecting rows from a data frame

> dim(cars)
[1] 50  2
> data.frame(a=cars[1,], b=cars[2, ])
  a.speed a.dist b.speed b.dist
1       4      2       4     10
> dim(data.frame(a=cars[1,], b=cars[2, ]))
[1] 1 4
> cars2 = as.matrix(cars)
> data.frame(a=cars2[1,], b=cars2[2, ])
      a  b
speed 4  4
dist  2 10

Creating data frame using structure() function

Creating data frame using structure() function in R

Create an empty data.frame

https://stackoverflow.com/questions/10689055/create-an-empty-data-frame

# the column types default as logical per vector(), but are then overridden
a = data.frame(matrix(vector(), 5, 3,
               dimnames=list(c(), c("Date", "File", "User"))),
               stringsAsFactors=F)
str(a) # NA but they are logical , not numeric.
a[1,1] <- rnorm(1)
str(a)

# similar to above
a <- data.frame(matrix(NA, nrow = 2, ncol = 3))

# different data type
a <- data.frame(x1 = character(),
                x2 = numeric(),
                x3 = factor(),
                stringsAsFactors = FALSE)

Objects from subsetting a row in a data frame vs matrix

  • Subsetting creates repeated rows. This will create unexpected rownames.
    R> z <- data.frame(x=1:3, y=2:4)
    R> rownames(z) <- letters[1:3]
    R> rownames(z)[c(1,1)]
    [1] "a" "a"
    R> rownames(z[c(1,1),])
    [1] "a"   "a.1"
    R> z[c(1,1), ]
        x y
    a   1 2
    a.1 1 2
    
  • Convert a dataframe to a vector (by rows) The solution is as.vector(t(mydf[i, ])) or c(mydf[i, ]). My example:
    str(trainData)
    # 'data.frame':	503 obs. of  500 variables:
    #  $ bm001: num  0.429 1 -0.5 1.415 -1.899 ...
    #  $ bm002: num  0.0568 1 0.5 0.3556 -1.16 ...
    # ...
    trainData[1:3, 1:3]
    #        bm001      bm002    bm003
    # 1  0.4289449 0.05676296 1.657966
    # 2  1.0000000 1.00000000 1.000000
    # 3 -0.5000000 0.50000000 0.500000
    o <- data.frame(time = trainData[1, ], status = trainData[2, ], treat = trainData[3, ], t(TData))
    # Warning message:
    # In data.frame(time = trainData[1, ], status = trainData[2, ], treat = trainData[3,  :
    #   row names were found from a short variable and have been discarded
    

    'trees' data from the 'datasets' package

    trees[1:3,]
    #   Girth Height Volume
    # 1   8.3     70   10.3
    # 2   8.6     65   10.3
    # 3   8.8     63   10.2
    
    # Wrong ways:
    data.frame(trees[1,] , trees[2,])
    #   Girth Height Volume Girth.1 Height.1 Volume.1
    # 1   8.3     70   10.3     8.6       65     10.3
    data.frame(time=trees[1,] , status=trees[2,])
    #   time.Girth time.Height time.Volume status.Girth status.Height status.Volume
    # 1        8.3          70        10.3          8.6            65          10.3
    data.frame(time=as.vector(trees[1,]) , status=as.vector(trees[2,]))
    #   time.Girth time.Height time.Volume status.Girth status.Height status.Volume
    # 1        8.3          70        10.3          8.6            65          10.3
    data.frame(time=c(trees[1,]) , status=c(trees[2,]))
    # time.Girth time.Height time.Volume status.Girth status.Height status.Volume
    # 1        8.3          70        10.3          8.6            65          10.3
    
    # Right ways:
    # method 1: dropping row names
    data.frame(time=c(t(trees[1,])) , status=c(t(trees[2,]))) 
    # OR
    data.frame(time=as.numeric(trees[1,]) , status=as.numeric(trees[2,]))
    #   time status
    # 1  8.3    8.6
    # 2 70.0   65.0
    # 3 10.3   10.3
    # method 2: keeping row names
    data.frame(time=t(trees[1,]) , status=t(trees[2,]))
    #          X1   X2
    # Girth   8.3  8.6
    # Height 70.0 65.0
    # Volume 10.3 10.3
    data.frame(time=unlist(trees[1,]) , status=unlist(trees[2,]))
    #        time status
    # Girth   8.3    8.6
    # Height 70.0   65.0
    # Volume 10.3   10.3
    
    # Method 3: convert a data frame to a matrix
    is.matrix(trees)
    # [1] FALSE
    trees2 <- as.matrix(trees)
    data.frame(time=trees2[1,] , status=trees2[2,]) # row names are kept
    #        time status
    # Girth   8.3    8.6
    # Height 70.0   65.0
    # Volume 10.3   10.3
    
    dim(trees[1,])
    # [1] 1 3
    dim(trees2[1, ])
    # NULL
    trees[1, ]  # notice the row name '1' on the left hand side
    #   Girth Height Volume
    # 1   8.3     70   10.3
    trees2[1, ]
    #  Girth Height Volume
    #    8.3   70.0   10.3
    

Convert a list to data frame

How to Convert a List to a Data Frame in R.

# method 1
data.frame(t(sapply(my_list,c)))

# method 2
library(dplyr)
bind_rows(my_list) # OR bind_cols(my_list)

# method 3
library(data.table)
rbindlist(my_list)

tibble and data.table

Clean a dataset

How to clean the datasets in R

matrix

Define and subset a matrix

  • Matrix in R
    • It is clear when a vector becomes a matrix the data is transformed column-wisely (byrow = FALSE, by default).
    • When subsetting a matrix, it follows the format: X[rows, colums] or X[y-axis, x-axis].
data <- c(2, 4, 7, 5, 10, 1)
A <- matrix(data, ncol = 3)
print(A)
#      [,1] [,2] [,3]
# [1,]    2    7   10
# [2,]    4    5    1

A[1:1, 2:3, drop=F]
#      [,1] [,2]
# [1,]    7   10

Prevent automatic conversion of single column to vector

use drop = FALSE such as mat[, 1, drop = FALSE].

complete.cases(): remove rows with missing in any column

It works on a sequence of vectors, matrices and data frames.

NROW vs nrow

?nrow. Use NROW/NCOL instead of nrow/ncol to treat vectors as 1-column matrices.

matrix (column-major order) multiply a vector

> matrix(1:6, 3,2)
     [,1] [,2]
[1,]    1    4
[2,]    2    5
[3,]    3    6
> matrix(1:6, 3,2) * c(1,2,3) # c(1,2,3) will be recycled to form a matrix. Good quiz.
     [,1] [,2]
[1,]    1    4
[2,]    4   10
[3,]    9   18
> matrix(1:6, 3,2) * c(1,2,3,4) # c(1,2,3,4) will be recycled
     [,1] [,2]
[1,]    1   16
[2,]    4    5
[3,]    9   12

add a vector to all rows of a matrix

add a vector to all rows of a matrix. sweep() or rep() is the best.

sparse matrix

R convert matrix or data frame to sparseMatrix

To subset a vector from some column of a sparseMatrix, we need to convert it to a regular vector, as.vector().

Attributes

Names

Useful functions for dealing with object names. (Un)Setting object names: stats::setNames(), unname() and rlang::set_names()

Print a vector by suppressing names

Use unname. sapply(, , USE.NAMES = FALSE).

format.pval/print p-values/format p values

format.pval(). By default it will show 5 significant digits (getOption("digits")-2).

> set.seed(1); format.pval(c(stats::runif(5), pi^-100, NA))
[1] "0.26551" "0.37212" "0.57285" "0.90821" "0.20168" "< 2e-16" "NA"
> format.pval(c(0.1, 0.0001, 1e-27))
[1] "1e-01"  "1e-04"  "<2e-16"

R> pvalue
[1] 0.0004632104
R> print(pvalue, digits =20)
[1] 0.00046321036188223807528
R> format.pval(pvalue)
[1] "0.00046321"
R> format.pval(pvalue * 1e-1)
[1] "4.6321e-05"
R> format.pval(0.00004632)
[1] "4.632e-05"
R> getOption("digits")
[1] 7

Return type

The format.pval() function returns a string, so it’s not appropriate to use the returned object for operations like sorting.

Wrong number of digits in format.pval()

See here. The solution is to apply round() and then format.pval().

x <- c(6.25433625041843e-05, NA, 0.220313341361346, NA, 0.154029880744594, 
   0.0378437685448703, 0.023358329881356, NA, 0.0262561986351483, 
   0.000251274794673796) 
format.pval(x, digits=3)
# [1] "6.25e-05" "NA"       "0.220313" "NA"       "0.154030" "0.037844" "0.023358"
# [8] "NA"       "0.026256" "0.000251"

round(x, 3) |> format.pval(digits=3, eps=.001)
# [1] "<0.001" "NA"     "0.220"  "NA"     "0.154"  "0.038"  "0.023"  "NA"
# [9] "0.026"  "<0.001"

dplr::mutate_if()

library(dplyr)
df <- data.frame(
  char_var = c("A", "B", "C"),
  num_var1 = c(1.123456, 2.123456, 3.123456),
  num_var2 = c(4.654321, 5.654321, 6.654321),
  stringsAsFactors = FALSE
)

# Round numerical variables to 4 digits after the decimal point
df_rounded <- df %>%
  mutate_if(is.numeric, round, digits = 4)

Customize R: options()

Change the default R repository, my .Rprofile

Change R repository

Edit global Rprofile file. On *NIX platforms, it's located in /usr/lib/R/library/base/R/Rprofile although local .Rprofile settings take precedence.

For example, I can specify the R mirror I like by creating a single line .Rprofile file under my home directory. Another good choice of repository is cloud.r-project.org.

Type file.edit("~/.Rprofile")

local({
  r = getOption("repos")
  r["CRAN"] = "https://cran.rstudio.com/"
  options(repos = r)
})
options(continue = "  ", editor = "nano")
message("Hi MC, loading ~/.Rprofile")
if (interactive()) {
  .Last <- function() try(savehistory("~/.Rhistory"))
}

Change the default web browser for utils::browseURL()

When I run help.start() function in LXLE, it cannot find its default web browser (seamonkey). The solution is to put

options(browser='seamonkey')

in the .Rprofile of your home directory. If the browser is not in the global PATH, we need to put the full path above.

For one-time only purpose, we can use the browser option in help.start() function:

> help.start(browser="seamonkey")
If the browser launched by 'seamonkey' is already running, it is *not*
    restarted, and you must switch to its window.
Otherwise, be patient ...

We can work made a change (or create the file) ~/.Renviron or etc/Renviron. See

Change the default editor

On my Linux and mac, the default editor is "vi". To change it to "nano",

options(editor = "nano")

Change prompt and remove '+' sign

See https://stackoverflow.com/a/1448823.

options(prompt="R> ", continue=" ")

digits

  • signif() rounds x to n significant digits.
    R> signif(pi, 3)
    [1] 3.14
    R> signif(pi, 5)
    [1] 3.1416
    
  • The default digits 7 may be too small. For example, if a number is very large, then we may not be able to see (enough) value after the decimal point. The acceptable range is 1-22. See the following examples

In R,

> options()$digits # Default
[1] 7
> print(.1+.2, digits=18)
[1] 0.300000000000000044
> 100000.07 + .04
[1] 100000.1
> options(digits = 16)
> 100000.07 + .04
[1] 100000.11

In Python,

>>> 100000.07 + .04
100000.11

Disable scientific notation in printing: options(scipen)

How to Turn Off Scientific Notation in R?

This also helps with write.table() results. For example, 0.0003 won't become 3e-4 in the output file.

> numer = 29707; denom = 93874
> c(numer/denom, numer, denom) 
[1] 3.164561e-01 2.970700e+04 9.387400e+04

# Method 1. Without changing the global option
> format(c(numer/denom, numer, denom), scientific=FALSE)
[1] "    0.3164561" "29707.0000000" "93874.0000000"

# Method 2. Change the global option
> options(scipen=999)
> numer/denom
[1] 0.3164561
> c(numer/denom, numer, denom)
[1]     0.3164561 29707.0000000 93874.0000000
> c(4/5, numer, denom)
[1]     0.8 29707.0 93874.0

Suppress warnings: options() and capture.output()

Use options(). If warn is negative all warnings are ignored. If warn is zero (the default) warnings are stored until the top--level function returns.

op <- options("warn")
options(warn = -1)
....
options(op)

# OR
warnLevel <- options()$warn
options(warn = -1)
...
options(warn = warnLevel)

suppressWarnings()

suppressWarnings( foo() )

foo <- capture.output( 
 bar <- suppressWarnings( 
 {print( "hello, world" ); 
   warning("unwanted" )} ) ) 

capture.output()

str(iris, max.level=1) %>% capture.output(file = "/tmp/iris.txt")

Converts warnings into errors

options(warn=2)

demo() function

  • How to wait for a keypress in R? PS readline() is different from readLines().
    for(i in 1:2) { print(i); readline("Press [enter] to continue")}
    
  • Hit 'ESC' or Ctrl+c to skip the prompt "Hit <Return> to see next plot:"
  • demo() uses options() to ask users to hit Enter on each plot
    op <- options(device.ask.default = ask)  # ask = TRUE
    on.exit(options(op), add = TRUE)
    

sprintf

paste, paste0, sprintf

this post, 3 R functions that I enjoy

sep vs collapse in paste()

  • sep is used if we supply multiple separate objects to paste(). A more powerful function is tidyr::unite() function.
  • collapse is used to make the output of length 1. It is commonly used if we have only 1 input object
R> paste("a", "A", sep=",") # multi-vec -> multi-vec
[1] "a,A"
R> paste(c("Elon", "Taylor"), c("Mask", "Swift"))
[1] "Elon Mask"    "Taylor Swift"
# OR
R> sprintf("%s, %s", c("Elon", "Taylor"), c("Mask", "Swift"))

R> paste(c("a", "A"), collapse="-") # one-vec/multi-vec  -> one-scale
[1] "a-A"

# When use together, sep first and collapse second
R> paste(letters[1:3], LETTERS[1:3], sep=",", collapse=" - ")
[1] "a,A - b,B - c,C"
R> paste(letters[1:3], LETTERS[1:3], sep=",")
[1] "a,A" "b,B" "c,C"
R> paste(letters[1:3], LETTERS[1:3], sep=",") |> paste(collapse=" - ")
[1] "a,A - b,B - c,C"

Format number as fixed width, with leading zeros

# sprintf()
a <- seq(1,101,25)
sprintf("name_%03d", a)
[1] "name_001" "name_026" "name_051" "name_076" "name_101"

# formatC()
paste("name", formatC(a, width=3, flag="0"), sep="_")
[1] "name_001" "name_026" "name_051" "name_076" "name_101"

# gsub()
paste0("bm", gsub(" ", "0", format(5:15)))
# [1] "bm05" "bm06" "bm07" "bm08" "bm09" "bm10" "bm11" "bm12" "bm13" "bm14" "bm15"

formatC and prettyNum (prettifying numbers)

R> (x <- 1.2345 * 10 ^ (-8:4))
 [1] 1.2345e-08 1.2345e-07 1.2345e-06 1.2345e-05 1.2345e-04 1.2345e-03
 [7] 1.2345e-02 1.2345e-01 1.2345e+00 1.2345e+01 1.2345e+02 1.2345e+03
[13] 1.2345e+04
R> formatC(x)
 [1] "1.234e-08" "1.234e-07" "1.234e-06" "1.234e-05" "0.0001234" "0.001234"
 [7] "0.01235"   "0.1235"    "1.234"     "12.34"     "123.4"     "1234"
[13] "1.234e+04"
R> formatC(x, digits=3)
 [1] "1.23e-08" "1.23e-07" "1.23e-06" "1.23e-05" "0.000123" "0.00123"
 [7] "0.0123"   "0.123"    "1.23"     "12.3"     " 123"     "1.23e+03"
[13] "1.23e+04"
R> formatC(x, digits=3, format="e")
 [1] "1.234e-08" "1.234e-07" "1.234e-06" "1.234e-05" "1.234e-04" "1.234e-03"
 [7] "1.235e-02" "1.235e-01" "1.234e+00" "1.234e+01" "1.234e+02" "1.234e+03"
[13] "1.234e+04"

R> x <- .000012345
R> prettyNum(x)
[1] "1.2345e-05"
R> x <- .00012345
R> prettyNum(x)
[1] "0.00012345"

format(x, scientific = TRUE) vs round() vs format.pval()

Print numeric data in exponential format, so .0001 prints as 1e-4

format(c(0.00001156, 0.84134, 2.1669), scientific = T, digits=4)
# [1] "1.156e-05" "8.413e-01" "2.167e+00"
round(c(0.00001156, 0.84134, 2.1669), digits=4)
# [1] 0.0000 0.8413 2.1669

format.pval(c(0.00001156, 0.84134, 2.1669)) # output is char vector
# [1] "1.156e-05" "0.84134"   "2.16690"
format.pval(c(0.00001156, 0.84134, 2.1669), digits=4)
# [1] "1.156e-05" "0.8413"    "2.1669"

Creating publication quality graphs in R

HDF5 : Hierarchical Data Format

HDF5 is an open binary file format for storing and managing large, complex datasets. The file format was developed by the HDF Group, and is widely used in scientific computing.

Formats for writing/saving and sharing data

Efficiently Saving and Sharing Data in R

Write unix format files on Windows and vice versa

https://stat.ethz.ch/pipermail/r-devel/2012-April/063931.html

with() and within() functions

closePr <- with(mariokart, totalPr - shipPr)
head(closePr, 20)

mk <- within(mariokart, {
             closePr <- totalPr - shipPr
     })
head(mk) # new column closePr

mk <- mariokart
aggregate(. ~ wheels + cond, mk, mean)
# create mean according to each level of (wheels, cond)

aggregate(totalPr ~ wheels + cond, mk, mean)

tapply(mk$totalPr, mk[, c("wheels", "cond")], mean)

stem(): stem-and-leaf plot (alternative to histogram), bar chart on terminals

Plot histograms as lines

https://stackoverflow.com/a/16681279. This is useful when we want to compare the distribution from different statistics.

x2=invisible(hist(out2$EB))
y2=invisible(hist(out2$Bench))
z2=invisible(hist(out2$EB0.001))

plot(x=x2$mids, y=x2$density, type="l")
lines(y2$mids, y2$density, lty=2, pwd=2)
lines(z2$mids, z2$density, lty=3, pwd=2)

Histogram with density line

hist(x, prob = TRUE)
lines(density(x), col = 4, lwd = 2)

The overlayed density may looks strange in cases for example counts from single-cell RNASeq or p-values from RNASeq (there is a peak around x=0).

Graphical Parameters, Axes and Text, Combining Plots

statmethods.net

15 Questions All R Users Have About Plots

See 15 Questions All R Users Have About Plots. This is a tremendous post. It covers the built-in plot() function and ggplot() from ggplot2 package.

  1. How To Draw An Empty R Plot? plot.new()
  2. How To Set The Axis Labels And Title Of The R Plots?
  3. How To Add And Change The Spacing Of The Tick Marks Of Your R Plot? axis()
  4. How To Create Two Different X- or Y-axes? par(new=TRUE), axis(), mtext(). ?par.
  5. How To Add Or Change The R Plot’s Legend? legend()
  6. How To Draw A Grid In Your R Plot? grid()
  7. How To Draw A Plot With A PNG As Background? rasterImage() from the png package
  8. How To Adjust The Size Of Points In An R Plot? cex argument
  9. How To Fit A Smooth Curve To Your R Data? loess() and lines()
  10. How To Add Error Bars In An R Plot? arrows()
  11. How To Save A Plot As An Image On Disc
  12. How To Plot Two R Plots Next To Each Other? par(mfrow)[which means Multiple Figures (use ROW-wise)], gridBase package, lattice package
  13. How To Plot Multiple Lines Or Points? plot(), lines()
  14. How To Fix The Aspect Ratio For Your R Plots? asp parameter
  15. What Is The Function Of hjust And vjust In ggplot2?

jitter function

Jitterbox.png

Scatterplot with the "rug" function

require(stats)  # both 'density' and its default method
with(faithful, {
    plot(density(eruptions, bw = 0.15))
    rug(eruptions)
    rug(jitter(eruptions, amount = 0.01), side = 3, col = "light blue")
})

File:RugFunction.png

See also the stripchart() function which produces one dimensional scatter plots (or dot plots) of the given data.

Identify/Locate Points in a Scatter Plot

  • ?identify
  • Using the identify function in R
    plot(x, y)
    identify(x, y, labels = names, plot = TRUE) 
    # Use left clicks to select points we want to identify and "esc" to stop the process
    # This will put the labels on the plot and also return the indices of points
    # [1] 143
    names[143]
    

Draw a single plot with two different y-axes

Draw Color Palette

Default palette before R 4.0

palette() # black, red, green3, blue, cyan, magenta, yellow, gray

# Example from Coursera "Statistics for Genomic Data Science" by Jeff Leek
tropical = c('darkorange', 'dodgerblue', 'hotpink', 'limegreen', 'yellow')
palette(tropical)
plot(1:5, 1:5, col=1:5, pch=16, cex=5)

New palette in R 4.0.0

R 4.0: 3 new features, R 4.0.0 now available, and a look back at R's history. For example, we can select "ggplot2" palette to make the base graphics charts that match the color scheme of ggplot2.

R> palette() 
[1] "black"   "#DF536B" "#61D04F" "#2297E6" "#28E2E5" "#CD0BBC" "#F5C710"
[8] "gray62"
R> palette.pals()
 [1] "R3"              "R4"              "ggplot2"        
 [4] "Okabe-Ito"       "Accent"          "Dark 2"         
 [7] "Paired"          "Pastel 1"        "Pastel 2"       
[10] "Set 1"           "Set 2"           "Set 3"          
[13] "Tableau 10"      "Classic Tableau" "Polychrome 36"  
[16] "Alphabet"
R> palette.colors(palette='R4') # same as palette()
[1] "#000000" "#DF536B" "#61D04F" "#2297E6" "#28E2E5" "#CD0BBC" "#F5C710"
[8] "#9E9E9E"
R> palette("R3")  # nothing return on screen but palette has changed
R> palette() 
[1] "black"   "red"     "green3"  "blue"    "cyan"    "magenta" "yellow" 
[8] "gray"  
R> palette("R4") # reset to the default color palette; OR palette("default")

R> scales::show_col(palette.colors(palette = "Okabe-Ito"))
R> for(id in palette.pals()) { 
     scales::show_col(palette.colors(palette = id))
     title(id)
     readline("Press [enter] to continue") 
   } 

The palette function can also be used to change the color palette. See Setting up Color Palettes in R

palette("ggplot2")
palette(palette()[-1]) # Remove 'black'
   # OR palette(palette.colors(palette = "ggplot2")[-1] )
with(iris, plot(Sepal.Length, Petal.Length, col = Species, pch=16))

cc <- palette()
palette(c(cc,"purple","brown")) # Add two colors
R> colors() |> length() # [1] 657
R> colors(distinct = T) |> length() # [1] 502

evoPalette

Evolve new colour palettes in R with evoPalette

rtist

rtist: Use the palettes of famous artists in your own visualizations.

SVG

Embed svg in html

svglite

svglite is better R's svg(). It was used by ggsave(). svglite 1.2.0, R Graphics Cookbook.

pdf -> svg

Using Inkscape. See this post.

svg -> png

SVG to PNG using the gyro package

read.table

clipboard

source("clipboard")
read.table("clipboard")

inline text

mydf <- read.table(header=T, text='
 cond yval
    A 2
    B 2.5
    C 1.6
')

http(s) connection

temp = getURL("https://gist.github.com/arraytools/6743826/raw/23c8b0bc4b8f0d1bfe1c2fad985ca2e091aeb916/ip.txt", 
                           ssl.verifypeer = FALSE)
ip <- read.table(textConnection(temp), as.is=TRUE)

read only specific columns

Use 'colClasses' option in read.table, read.delim, .... For example, the following example reads only the 3rd column of the text file and also changes its data type from a data frame to a vector. Note that we have include double quotes around NULL.

x <- read.table("var_annot.vcf", colClasses = c(rep("NULL", 2), "character", rep("NULL", 7)), 
                skip=62, header=T, stringsAsFactors = FALSE)[, 1]
# 
system.time(x <- read.delim("Methylation450k.txt", 
                colClasses = c("character", "numeric", rep("NULL", 188)), stringsAsFactors = FALSE))

To know the number of columns, we might want to read the first row first.

library(magrittr)
scan("var_annot.vcf", sep="\t", what="character", skip=62, nlines=1, quiet=TRUE) %>% length()

Another method is to use pipe(), cut or awk. See ways to read only selected columns from a file into R

check.names = FALSE in read.table()

gx <- read.table(file, header = T, row.names =1)
colnames(gx) %>% grep("[^[:alnum:] ]", ., value = TRUE)
# [1] "hCG_1642354" "IGH."        "IGHV1.69"    "IGKV1.5"     "IGKV2.24"    "KRTAP13.2"  
# [7] "KRTAP19.1"   "KRTAP2.4"    "KRTAP5.9"    "KRTAP6.3"    "Kua.UEV"  

gx <- read.table(file, header = T, row.names =1, check.names = FALSE)
colnames(gx) %>% grep("[^[:alnum:] ]", ., value = TRUE)
# [1] "hCG_1642354" "IGH@"        "IGHV1-69"    "IGKV1-5"     "IGKV2-24"    "KRTAP13-2"  
# [7] "KRTAP19-1"   "KRTAP2-4"    "KRTAP5-9"    "KRTAP6-3"    "Kua-UEV"  

setNames()

Change the colnames. See an example from tidymodels

Testing for valid variable names

Testing for valid variable names

make.names(): Make syntactically valid names out of character vectors

  • make.names()
  • A valid variable name consists of letters, numbers and the dot or underline characters. The variable name starts with a letter or the dot not followed by a number. See R variables.
make.names("abc-d") # [1] "abc.d"

Serialization

If we want to pass an R object to C (use recv() function), we can use writeBin() to output the stream size and then use serialize() function to output the stream to a file. See the post on R mailing list.

> a <- list(1,2,3)
> a_serial <- serialize(a, NULL)
> a_length <- length(a_serial)
> a_length
[1] 70
> writeBin(as.integer(a_length), connection, endian="big")
> serialize(a, connection)

In C++ process, I receive one int variable first to get the length, and then read <length> bytes from the connection.

socketConnection

See ?socketconnection.

Simple example

from the socketConnection's manual.

Open one R session

con1 <- socketConnection(port = 22131, server = TRUE) # wait until a connection from some client
writeLines(LETTERS, con1)
close(con1)

Open another R session (client)

con2 <- socketConnection(Sys.info()["nodename"], port = 22131)
# as non-blocking, may need to loop for input
readLines(con2)
while(isIncomplete(con2)) {
   Sys.sleep(1)
   z <- readLines(con2)
   if(length(z)) print(z)
}
close(con2)

Use nc in client

The client does not have to be the R. We can use telnet, nc, etc. See the post here. For example, on the client machine, we can issue

nc localhost 22131   [ENTER]

Then the client will wait and show anything written from the server machine. The connection from nc will be terminated once close(con1) is given.

If I use the command

nc -v -w 2 localhost -z 22130-22135

then the connection will be established for a short time which means the cursor on the server machine will be returned. If we issue the above nc command again on the client machine it will show the connection to the port 22131 is refused. PS. "-w" switch denotes the number of seconds of the timeout for connects and final net reads.

Some post I don't have a chance to read. http://digitheadslabnotebook.blogspot.com/2010/09/how-to-send-http-put-request-from-r.html

Use curl command in client

On the server,

con1 <- socketConnection(port = 8080, server = TRUE)

On the client,

curl --trace-ascii debugdump.txt http://localhost:8080/

Then go to the server,

while(nchar(x <- readLines(con1, 1)) > 0) cat(x, "\n")

close(con1) # return cursor in the client machine

Use telnet command in client

On the server,

con1 <- socketConnection(port = 8080, server = TRUE)

On the client,

sudo apt-get install telnet
telnet localhost 8080
abcdefg
hijklmn
qestst

Go to the server,

readLines(con1, 1)
readLines(con1, 1)
readLines(con1, 1)
close(con1) # return cursor in the client machine

Some tutorial about using telnet on http request. And this is a summary of using telnet.

Subsetting

Subset assignment of R Language Definition and Manipulation of functions.

The result of the command x[3:5] <- 13:15 is as if the following had been executed

`*tmp*` <- x
x <- "[<-"(`*tmp*`, 3:5, value=13:15)
rm(`*tmp*`)

Avoid Coercing Indices To Doubles

1 or 1L

Careful on NA value

See the example below. base::subset() or dplyr::filter() can remove NA subsets.

R> mydf = data.frame(a=1:3, b=c(NA,5,6))
R> mydf[mydf$b >5, ]
    a  b
NA NA NA
3   3  6
R> mydf[which(mydf$b >5), ]
  a b
3 3 6
R> mydf %>% dplyr::filter(b > 5)
  a b
1 3 6
R> subset(mydf, b>5)
  a b
3 3 6

Implicit looping

set.seed(1)
i <- sample(c(TRUE, FALSE), size=10, replace = TRUE)
# [1]  TRUE FALSE  TRUE  TRUE FALSE  TRUE  TRUE  TRUE FALSE FALSE
sum(i)        # [1] 6
x <- 1:10
length(x[i])  # [1] 6
x[i[1:3]]     # [1]  1  3  4  6  7  9 10
length(x[i[1:3]]) # [1] 7

modelling

update()

Extract all variable names in lm(), glm(), ...

all.vars(formula(Model)[-2])

as.formula(): use a string in formula in lm(), glm(), ...

? as.formula
xnam <- paste("x", 1:25, sep="")
fmla <- as.formula(paste("y ~ ", paste(xnam, collapse= "+")))
outcome <- "mpg"
variables <- c("cyl", "disp", "hp", "carb")

# Method 1. The 'Call' portion of the model is reported as “formula = f” 
# our modeling effort, 
# fully parameterized!
f <- as.formula(
  paste(outcome, 
        paste(variables, collapse = " + "), 
        sep = " ~ "))
print(f)
# mpg ~ cyl + disp + hp + carb

model <- lm(f, data = mtcars)
print(model)

# Call:
#   lm(formula = f, data = mtcars)
# 
# Coefficients:
#   (Intercept)          cyl         disp           hp         carb  
#     34.021595    -1.048523    -0.026906     0.009349    -0.926863  

# Method 2. eval() + bquote() + ".()"
format(terms(model))  #  or model$terms
# [1] "mpg ~ cyl + disp + hp + carb"

# The new line of code
model <- eval(bquote(   lm(.(f), data = mtcars)   ))

print(model)
# Call:
#   lm(formula = mpg ~ cyl + disp + hp + carb, data = mtcars)
# 
# Coefficients:
#   (Intercept)          cyl         disp           hp         carb  
#     34.021595    -1.048523    -0.026906     0.009349    -0.926863  

# Note if we skip ".()" operator
> eval(bquote(   lm(f, data = mtcars)   ))

Call:
lm(formula = f, data = mtcars)

Coefficients:
(Intercept)          cyl         disp           hp         carb  
  34.021595    -1.048523    -0.026906     0.009349    -0.926863 

reformulate

Simplifying Model Formulas with the R Function ‘reformulate()’

I() function

I() means isolates. See What does the capital letter "I" in R linear regression formula mean?, In R formulas, why do I have to use the I() function on power terms, like y ~ I(x^3)

Aggregating results from linear model

https://stats.stackexchange.com/a/6862

Replacement function "fun(x) <- a"

What are Replacement Functions in R?

R> xx <- c(1,3,66, 99)
R> "cutoff<-" <- function(x, value){
     x[x > value] <- Inf
     x
 }
R> cutoff(xx) <- 65 # xx & 65 are both input
R> xx
[1]   1   3 Inf Inf

R> "cutoff<-"(x = xx, value = 65)
[1]   1   3 Inf Inf

The statement fun(x) <- a and R will read x <- "fun<-"(x,a)

S3 and S4 methods and signature

Debug an S4 function

  • showMethods('FUNCTION')
  • getMethod('FUNCTION', 'SIGNATURE')
  • debug(, signature)
> args(debug)
function (fun, text = "", condition = NULL, signature = NULL) 

> library(genefilter) # Bioconductor
> showMethods("nsFilter")
Function: nsFilter (package genefilter)
eset="ExpressionSet"
> debug(nsFilter, signature="ExpressionSet")

library(DESeq2)
showMethods("normalizationFactors") # show the object class
                                    # "DESeqDataSet" in this case.
getMethod(`normalizationFactors`, "DESeqDataSet") # get the source code

See the source code of normalizationFactors<- (setReplaceMethod() is used) and the source code of estimateSizeFactors(). We can see how avgTxLength was used in estimateNormFactors().

Another example

library(GSVA)
args(gsva) # function (expr, gset.idx.list, ...)

showMethods("gsva")
# Function: gsva (package GSVA)
# expr="ExpressionSet", gset.idx.list="GeneSetCollection"
# expr="ExpressionSet", gset.idx.list="list"
# expr="matrix", gset.idx.list="GeneSetCollection"
# expr="matrix", gset.idx.list="list"
# expr="SummarizedExperiment", gset.idx.list="GeneSetCollection"
# expr="SummarizedExperiment", gset.idx.list="list"

debug(gsva, signature = c(expr="matrix", gset.idx.list="list"))
# OR
# debug(gsva, signature = c("matrix", "list"))
gsva(y, geneSets, method="ssgsea", kcdf="Gaussian")
Browse[3]> debug(.gsva)
# return(ssgsea(expr, gset.idx.list, alpha = tau, parallel.sz = parallel.sz, 
#      normalization = ssgsea.norm, verbose = verbose, 
#      BPPARAM = BPPARAM))

isdebugged("gsva")
# [1] TRUE
undebug(gsva)
library(IRanges)
ir <- IRanges(start=c(10, 20, 30), width=5)
ir

class(ir)
## [1] "IRanges"
## attr(,"package")
## [1] "IRanges"

getClassDef(class(ir))
## Class "IRanges" [package "IRanges"]
## 
## Slots:
##                                                                       
## Name:            start           width           NAMES     elementType
## Class:         integer         integer characterORNULL       character
##                                       
## Name:  elementMetadata        metadata
## Class: DataTableORNULL            list
## 
## Extends: 
## Class "Ranges", directly
## Class "IntegerList", by class "Ranges", distance 2
## Class "RangesORmissing", by class "Ranges", distance 2
## Class "AtomicList", by class "Ranges", distance 3
## Class "List", by class "Ranges", distance 4
## Class "Vector", by class "Ranges", distance 5
## Class "Annotated", by class "Ranges", distance 6
## 
## Known Subclasses: "NormalIRanges"

Check if a function is an S4 method

isS4(foo)

How to access the slots of an S4 object

  • @ will let you access the slots of an S4 object.
  • Note that often the best way to do this is to not access the slot directly but rather through an accessor function (e.g. coefs() rather than digging out the coefficients with $ or @). However, often such functions do not exist so you have to access the slots directly. This will mean that your code breaks if the internal implementation changes, however.
  • R - S4 Classes and Methods Hansen. getClass() or getClassDef().

setReplaceMethod()

See what methods work on an object

see what methods work on an object, e.g. a GRanges object:

methods(class="GRanges")

Or if you have an object, x:

methods(class=class(x))

View S3 function definition: double colon '::' and triple colon ':::' operators and getAnywhere()

?":::"

  • pkg::name returns the value of the exported variable name in namespace pkg
  • pkg:::name returns the value of the internal variable name
base::"+"
stats:::coef.default

predict.ppr
# Error: object 'predict.ppr' not found
stats::predict.ppr
# Error: 'predict.ppr' is not an exported object from 'namespace:stats'
stats:::predict.ppr  # OR  
getS3method("predict", "ppr")

getS3method("t", "test")

methods() + getAnywhere() functions

Read the source code (include Fortran/C, S3 and S4 methods)

S3 method is overwritten

For example, the select() method from dplyr is overwritten by grpreg package.

An easy solution is to load grpreg before loading dplyr.

mcols() and DataFrame() from Bioc S4Vectors package

  • mcols: Get or set the metadata columns.
  • colData: SummarizedExperiment instances from GenomicRanges
  • DataFrame: The DataFrame class extends the DataTable virtual class and supports the storage of any type of object (with length and [ methods) as columns.

For example, in Shrinkage of logarithmic fold changes vignette of the DESeq2paper package

> mcols(ddsNoPrior[genes, ])
DataFrame with 2 rows and 21 columns
   baseMean   baseVar   allZero dispGeneEst    dispFit dispersion  dispIter dispOutlier   dispMAP
  <numeric> <numeric> <logical>   <numeric>  <numeric>  <numeric> <numeric>   <logical> <numeric>
1  163.5750  8904.607     FALSE  0.06263141 0.03862798  0.0577712         7       FALSE 0.0577712
2  175.3883 59643.515     FALSE  2.25306109 0.03807917  2.2530611        12        TRUE 1.6011440
  Intercept strain_DBA.2J_vs_C57BL.6J SE_Intercept SE_strain_DBA.2J_vs_C57BL.6J WaldStatistic_Intercept
  <numeric>                 <numeric>    <numeric>                    <numeric>               <numeric>
1  6.210188                  1.735829    0.1229354                    0.1636645               50.515872
2  6.234880                  1.823173    0.6870629                    0.9481865                9.074686
  WaldStatistic_strain_DBA.2J_vs_C57BL.6J WaldPvalue_Intercept WaldPvalue_strain_DBA.2J_vs_C57BL.6J
                                <numeric>            <numeric>                            <numeric>
1                                10.60602         0.000000e+00                         2.793908e-26
2                                 1.92280         1.140054e-19                         5.450522e-02
   betaConv  betaIter  deviance  maxCooks
  <logical> <numeric> <numeric> <numeric>
1      TRUE         3  210.4045 0.2648753
2      TRUE         9  243.7455 0.3248949

Pipe

Packages take advantage of pipes

  • rstatix: Pipe-Friendly Framework for Basic Statistical Tests

findInterval()

Related functions are cuts() and split(). See also

Assign operator

  • Earlier versions of R used underscore (_) as an assignment operator.
  • Assignments with the = Operator
  • In R 1.8.0 (2003), the assign operator has been removed. See NEWS.
  • In R 1.9.0 (2004), "_" is allowed in valid names. See NEWS.
R162.png

Operator precedence

The ':' operator has higher precedence than '-' so 0:N-1 evaluates to (0:N)-1, not 0:(N-1) like you probably wanted.

order(), rank() and sort()

If we want to find the indices of the first 25 genes with the smallest p-values, we can use order(pval)[1:25].

> x = sample(10)
> x
 [1]  4  3 10  7  5  8  6  1  9  2
> order(x)
 [1]  8 10  2  1  5  7  4  6  9  3
> rank(x)
 [1]  4  3 10  7  5  8  6  1  9  2
> rank(10*x)
 [1]  4  3 10  7  5  8  6  1  9  2

> x[order(x)]
 [1]  1  2  3  4  5  6  7  8  9 10
> sort(x)
 [1]  1  2  3  4  5  6  7  8  9 10

relate order() and rank()

  • Order to rank: rank() = order(order())
    set.seed(1)
    x <- rnorm(5)
    order(x)
    # [1] 3 1 2 5 4
    rank(x)
    # [1] 2 3 1 5 4
    order(order(x))
    # [1] 2 3 1 5 4
    all(rank(x) == order(order(x)))
    # TRUE
  • Order to Rank method 2: rank(order()) = 1:n
    ord <- order(x)
    ranks <- integer(length(x))
    ranks[ord] <- seq_along(x)
    ranks
    # [1] 2 3 1 5 4
  • Rank to Order:
    ranks <- rank(x)
    ord <- order(ranks)
    ord
    # [1] 3 1 2 5 4

OS-dependent results on sorting string vector

Gene symbol case.

# mac: 
order(c("DC-UbP", "DC2")) # c(1,2)

# linux: 
order(c("DC-UbP", "DC2")) # c(2,1)

Affymetric id case.

# mac:
order(c("202800_at", "2028_s_at")) # [1] 2 1
sort(c("202800_at", "2028_s_at")) # [1] "2028_s_at" "202800_at"

# linux
order(c("202800_at", "2028_s_at")) # [1] 1 2
sort(c("202800_at", "2028_s_at")) # [1] "202800_at" "2028_s_at"

It does not matter if we include factor() on the character vector.

The difference is related to locale. See

# both mac and linux
stringr::str_order(c("202800_at", "2028_s_at")) # [1] 2 1
stringr::str_order(c("DC-UbP", "DC2")) # [1] 1 2

# Or setting the locale to "C"
Sys.setlocale("LC_ALL", "C"); sort(c("DC-UbP", "DC2"))
# Or
Sys.setlocale("LC_COLLATE", "C"); sort(c("DC-UbP", "DC2"))
# But not
Sys.setlocale("LC_ALL", "en_US.UTF-8"); sort(c("DC-UbP", "DC2"))

unique()

It seems it does not sort. ?unique.

# mac & linux
R> unique(c("DC-UbP", "DC2"))
[1] "DC-UbP" "DC2"

do.call

do.call constructs and executes a function call from a name or a function and a list of arguments to be passed to it.

The do.call() function in R: Unlocking Efficiency and Flexibility

Below are some examples from the help.

  • Usage
do.call(what, args, quote = FALSE, envir = parent.frame())
# what: either a function or a non-empty character string naming the function to be called.
# args: a list of arguments to the function call. The names attribute of args gives the argument names.
# quote: a logical value indicating whether to quote the arguments.
# envir: an environment within which to evaluate the call. This will be most useful
#        if what is a character string and the arguments are symbols or quoted expressions.
  • do.call() is similar to lapply() but not the same. It seems do.call() can make a simple function vectorized.
> do.call("complex", list(imag = 1:3))
[1] 0+1i 0+2i 0+3i
> lapply(list(imag = 1:3), complex)
$imag
[1] 0+0i
> complex(imag=1:3)
[1] 0+1i 0+2i 0+3i
> do.call(function(x) x+1, list(1:3))
[1] 2 3 4
  • Applying do.call with Multiple Arguments
> do.call("sum", list(c(1,2,3,NA), na.rm = TRUE))
[1] 6
> do.call("sum", list(c(1,2,3,NA) ))
[1] NA
> tmp <- expand.grid(letters[1:2], 1:3, c("+", "-"))
> length(tmp)
[1] 3
> tmp[1:4,]
  Var1 Var2 Var3
1    a    1    +
2    b    1    +
3    a    2    +
4    b    2    +
> c(tmp, sep = "")
$Var1
 [1] a b a b a b a b a b a b
Levels: a b

$Var2
 [1] 1 1 2 2 3 3 1 1 2 2 3 3

$Var3
 [1] + + + + + + - - - - - -
Levels: + -

$sep
[1] ""
> do.call("paste", c(tmp, sep = ""))
 [1] "a1+" "b1+" "a2+" "b2+" "a3+" "b3+" "a1-" "b1-" "a2-" "b2-" "a3-"
[12] "b3-"
  • environment and quote arguments.
> A <- 2
> f <- function(x) print(x^2)
> env <- new.env()
> assign("A", 10, envir = env)
> assign("f", f, envir = env)
> f <- function(x) print(x)
> f(A)   
[1] 2
> do.call("f", list(A))
[1] 2
> do.call("f", list(A), envir = env)  
[1] 4
> do.call(f, list(A), envir = env)   
[1] 2                       # Why?

> eval(call("f", A))                      
[1] 2
> eval(call("f", quote(A)))               
[1] 2
> eval(call("f", A), envir = env)         
[1] 4
> eval(call("f", quote(A)), envir = env)  
[1] 100
> foo <- function(a=1, b=2, ...) { 
         list(arg=do.call(c, as.list(match.call())[-1])) 
  }
> foo()
$arg
NULL
> foo(a=1)
$arg
a 
1 
> foo(a=1, b=2, c=3)
$arg
a b c 
1 2 3 
  • do.call() + switch(). See an example from Seurat::NormalizeData.
do.call(
   what = switch(
     EXPR = margin,
     '1' = 'rbind',
     '2' = 'cbind',
     stop("'margin' must be 1 or 2")
   ),
   args = normalized.data
)
switch('a', 'a' = rnorm(3), 'b'=rnorm(4)) # switch returns a value
do.call(switch('a', 'a' = 'rnorm', 'b'='rexp'), args=list(n=4)) # switch returns a function
  • The function we want to call is a string that may change: glmnet
# Suppose we want to call cv.glmnet or cv.coxnet or cv.lognet or cv.elnet .... depending on the case
fun = paste("cv", subclass, sep = ".")
cvstuff = do.call(fun, list(predmat,y,type.measure,weights,foldid,grouped))

expand.grid, mapply, vapply

A faster way to generate combinations for mapply and vapply

do.call vs mapply

  • do.call() is doing what mapply() does but do.call() uses a list instead of multiple arguments. So do.call() more close to base::Map() function.
> mapply(paste, tmp[1], tmp[2], tmp[3], sep = "")
      Var1 
 [1,] "a1+"
 [2,] "b1+"
 [3,] "a2+"
 [4,] "b2+"
 [5,] "a3+"
 [6,] "b3+"
 [7,] "a1-"
 [8,] "b1-"
 [9,] "a2-"
[10,] "b2-"
[11,] "a3-"
[12,] "b3-"
# It does not work if we do not explicitly specify the arguments in mapply()
> mapply(paste, tmp, sep = "")
      Var1 Var2 Var3
 [1,] "a"  "1"  "+" 
 [2,] "b"  "1"  "+" 
 [3,] "a"  "2"  "+" 
 [4,] "b"  "2"  "+" 
 [5,] "a"  "3"  "+" 
 [6,] "b"  "3"  "+" 
 [7,] "a"  "1"  "-" 
 [8,] "b"  "1"  "-" 
 [9,] "a"  "2"  "-" 
[10,] "b"  "2"  "-" 
[11,] "a"  "3"  "-" 
[12,] "b"  "3"  "-" 
set.seed(1)
mapply(rweibull, 1, c(1, 10), MoreArgs=list(n=1))
# [1] 1.326108 9.885284
set.seed(1)
x <- replicate(1000, mapply(rweibull, 1, c(1, 10), MoreArgs=list(n=1)))
dim(x) # [1]  2 1000
rowMeans(x)
# [1]  1.032209 10.104131
set.seed(1); Vectorize(rweibull)(n=1, shape=1, scale=c(1, 10))
# [1] 1.326108 9.885284
set.seed(1); x <- replicate(1000, Vectorize(rweibull)(n=1, shape=1, scale=c(1, 10)))

do.call vs lapply

What's the difference between lapply and do.call? It seems to me the best usage is combining both functions: do.call(..., lapply())

  • lapply returns a list of the same length as X, each element of which is the result of applying FUN to the corresponding element of X.
  • do.call constructs and executes a function call from a name or a function and a list of arguments to be passed to it. It is widely used, for example, to assemble lists into simpler structures (often with rbind or cbind).
  • Map applies a function to the corresponding elements of given vectors... Map is a simple wrapper to mapply which does not attempt to simplify the result, similar to Common Lisp's mapcar (with arguments being recycled, however). Future versions may allow some control of the result type.
> lapply(iris, class) # same as Map(class, iris)
$Sepal.Length
[1] "numeric"

$Sepal.Width
[1] "numeric"

$Petal.Length
[1] "numeric"

$Petal.Width
[1] "numeric"

$Species
[1] "factor"

> x <- lapply(iris, class)
> do.call(c, x)
Sepal.Length  Sepal.Width Petal.Length  Petal.Width      Species 
   "numeric"    "numeric"    "numeric"    "numeric"     "factor" 

https://stackoverflow.com/a/10801902

  • lapply applies a function over a list. So there will be several function calls.
  • do.call calls a function with a list of arguments (... argument) such as c() or rbind()/cbind() or sum or order or "[" or paste. So there is only one function call.
> X <- list(1:3,4:6,7:9)
> lapply(X,mean)
1
[1] 2

2
[1] 5

3
[1] 8
> do.call(sum, X)
[1] 45
> sum(c(1,2,3), c(4,5,6), c(7,8,9))
[1] 45
> do.call(mean, X) # Error
> do.call(rbind,X)
     [,1] [,2] [,3]
[1,]    1    2    3
[2,]    4    5    6
[3,]    7    8    9
> lapply(X,rbind)
1
     [,1] [,2] [,3]
[1,]    1    2    3

2
     [,1] [,2] [,3]
[1,]    4    5    6

3
     [,1] [,2] [,3]
[1,]    7    8    9
> mapply(mean, X, trim=c(0,0.5,0.1))
[1] 2 5 8
> mapply(mean, X) 
[1] 2 5 8

Below is a good example to show the difference of lapply() and do.call() - Generating Random Strings.

> set.seed(1)
> x <- replicate(2, sample(LETTERS, 4), FALSE)
> x
1
[1] "Y" "D" "G" "A"

2
[1] "B" "W" "K" "N"

> lapply(x, paste0)
1
[1] "Y" "D" "G" "A"

2
[1] "B" "W" "K" "N"

> lapply(x, paste0, collapse= "")
1
[1] "YDGA"

2
[1] "BWKN"

> do.call(paste0, x)
[1] "YB" "DW" "GK" "AN"

do.call + rbind + lapply

Lots of examples. See for example this one for creating a data frame from a vector.

x <- readLines(textConnection("---CLUSTER 1 ---
 3
 4
 5
 6
 ---CLUSTER 2 ---
 9
 10
 8
 11"))

 # create a list of where the 'clusters' are
 clust <- c(grep("CLUSTER", x), length(x) + 1L)

 # get size of each cluster
 clustSize <- diff(clust) - 1L

 # get cluster number
 clustNum <- gsub("[^0-9]+", "", x[grep("CLUSTER", x)])

 result <- do.call(rbind, lapply(seq(length(clustNum)), function(.cl){
     cbind(Object = x[seq(clust[.cl] + 1L, length = clustSize[.cl])]
         , Cluster = .cl
         )
     }))

 result

     Object Cluster
[1,] "3"    "1"
[2,] "4"    "1"
[3,] "5"    "1"
[4,] "6"    "1"
[5,] "9"    "2"
[6,] "10"   "2"
[7,] "8"    "2"
[8,] "11"   "2"

A 2nd example is to sort a data frame by using do.call(order, list()).

Another example is to reproduce aggregate(). aggregate() = do.call() + by().

attach(mtcars)
do.call(rbind, by(mtcars, list(cyl, vs), colMeans))
# the above approach give the same result as the following
# except it does not have an extra Group.x columns
aggregate(mtcars, list(cyl, vs), FUN=mean)

Run examples

When we call help(FUN), it shows the document in the browser. The browser will show

example(FUN, package = "XXX") was run in the console
To view output in the browser, the knitr package must be installed

How to get examples from help file, example()

Code examples in the R package manuals:

# How to run all examples from a man page
example(within)

# How to check your examples?
devtools::run_examples() 
testthat::test_examples()

See this post. Method 1:

example(acf, give.lines=TRUE)

Method 2:

Rd <- utils:::.getHelpFile(?acf)
tools::Rd2ex(Rd)

"[" and "[[" with the sapply() function

Suppose we want to extract string from the id like "ABC-123-XYZ" before the first hyphen.

sapply(strsplit("ABC-123-XYZ", "-"), "[", 1)

is the same as

sapply(strsplit("ABC-123-XYZ", "-"), function(x) x[1])

Dealing with dates

  • Simple examples
    dates <- c("January 15, 2023", "December 31, 1999")
    date_objects <- as.Date(dates, format = "%B %d, %Y") # format is for the input
    # [1] "2023-01-15" "1999-12-31"
  • Find difference
    # Convert the dates to Date objects
    date1 <- as.Date("6/29/21", format="%m/%d/%y")
    date2 <- as.Date("11/9/21", format="%m/%d/%y")
    
    # Calculate the difference in days
    diff_days <- as.numeric(difftime(date2, date1, units="days")) # 133
    # In months
    diff_days / (365.25/12)  # 4.36961   
    
    # OR using the lubridate package
    library(lubridate)
    # Convert the dates to Date objects
    date1 <- mdy("6/29/21")
    date2 <- mdy("11/9/21")
    interval(date1, date2) %/% months(1)
  • http://cran.r-project.org/web/packages/lubridate/vignettes/lubridate.html
    d1 = date()
    class(d1) # "character"
    d2 = Sys.Date()
    class(d2) # "Date"
    
    format(d2, "%a %b %d")
    
    library(lubridate); ymd("20140108") # "2014-01-08 UTC"
    mdy("08/04/2013") # "2013-08-04 UTC"
    dmy("03-04-2013") # "2013-04-03 UTC"
    ymd_hms("2011-08-03 10:15:03") # "2011-08-03 10:15:03 UTC"
    ymd_hms("2011-08-03 10:15:03", tz="Pacific/Auckland") 
    # "2011-08-03 10:15:03 NZST"
    ?Sys.timezone
    x = dmy(c("1jan2013", "2jan2013", "31mar2013", "30jul2013"))
    wday(x[1]) # 3
    wday(x[1], label=TRUE) # Tues
  • http://www.r-statistics.com/2012/03/do-more-with-dates-and-times-in-r-with-lubridate-1-1-0/
  • http://rpubs.com/seandavi/GEOMetadbSurvey2014
  • We want our dates and times as class "Date" or the class "POSIXct", "POSIXlt". For more information type ?POSIXlt.
  • anytime package
  • weeks to Christmas difftime(as.Date(“2019-12-25”), Sys.Date(), units =“weeks”)
  • A Comprehensive Introduction to Handling Date & Time in R 2020
  • Working with Dates and Times Pt 1
    • Three major functions: as.Date(), as.POSIXct(), and as.POSIXlt().
    • POSIXct is a class in R that represents date-time data. The ct stands for “calendar time” and it represents the (signed) number of seconds since the beginning of 1970 as a numeric vector1. It stores date time as integer.
    • POSIXlt is a class in R that represents date-time data. It stands for “local time” and is a list with components as integer vectors, which can represent a vector of broken-down times. It stores date time as list:sec, min, hour, mday, mon, year, wday, yday, isdst, zone, gmtoff.
  • R lubridate: How To Efficiently Work With Dates and Times in R 2023

Nonstandard/non-standard evaluation, deparse/substitute and scoping

f <- function(x) {
  substitute(x)
}
f(1:10)
# 1:10
class(f(1:10)) # or mode()
# [1] "call"
g <- function(x) deparse(substitute(x))
g(1:10)
# [1] "1:10"
class(g(1:10)) # or mode()
# [1] "character"
  • quote(expr) - similar to substitute() but do nothing?? noquote - print character strings without quotes
mode(quote(1:10))
# [1] "call"
  • eval(expr, envir), evalq(expr, envir) - eval evaluates its first argument in the current scope before passing it to the evaluator: evalq avoids this.
sample_df <- data.frame(a = 1:5, b = 5:1, c = c(5, 3, 1, 4, 1))

subset1 <- function(x, condition) {
  condition_call <- substitute(condition)
  r <- eval(condition_call, x)
  x[r, ]
}
x <- 4
condition <- 4
subset1(sample_df, a== 4) # same as subset(sample_df, a >= 4)
subset1(sample_df, a== x) # WRONG!
subset1(sample_df, a == condition) # ERROR

subset2 <- function(x, condition) {
  condition_call <- substitute(condition)
  r <- eval(condition_call, x, parent.frame())
  x[r, ]
}
subset2(sample_df, a == 4) # same as subset(sample_df, a >= 4)
subset2(sample_df, a == x) # 👌 
subset2(sample_df, a == condition) # 👍
  • deparse(expr) - turns unevaluated expressions into character strings. For example,
> deparse(args(lm))
[1] "function (formula, data, subset, weights, na.action, method = \"qr\", " 
[2] "    model = TRUE, x = FALSE, y = FALSE, qr = TRUE, singular.ok = TRUE, "
[3] "    contrasts = NULL, offset, ...) "                                    
[4] "NULL"     

> deparse(args(lm), width=20)
[1] "function (formula, data, "        "    subset, weights, "           
[3] "    na.action, method = \"qr\", " "    model = TRUE, x = FALSE, "   
[5] "    y = FALSE, qr = TRUE, "       "    singular.ok = TRUE, "        
[7] "    contrasts = NULL, "           "    offset, ...) "               
[9] "NULL"

Following is another example. Assume we have a bunch of functions (f1, f2, ...; each function implements a different algorithm) with same input arguments format (eg a1, a2). We like to run these function on the same data (to compare their performance).

f1 <- function(x) x+1; f2 <- function(x) x+2; f3 <- function(x) x+3

f1(1:3)
f2(1:3)
f3(1:3)

# Or
myfun <- function(f, a) {
    eval(parse(text = f))(a)
}
myfun("f1", 1:3)
myfun("f2", 1:3)
myfun("f3", 1:3)

# Or with lapply
method <- c("f1", "f2", "f3")
res <- lapply(method, function(M) {
                    Mres <- eval(parse(text = M))(1:3)
                    return(Mres)
})
names(res) <- method

library() accept both quoted and unquoted strings

How can library() accept both quoted and unquoted strings. The key lines are

  if (!character.only) 
     package <- as.character(substitute(package))

Lexical scoping

The ‘…’ argument

Functions

Function argument

Argument matching from R Language Definition manual.

Argument matching is augmented by the functions

Access to the partial matching algorithm used by R is via pmatch.

Check function arguments

Checking the inputs of your R functions: match.arg() , stopifnot()

stopifnot(): function argument sanity check

  • stopifnot(). stopifnot is a quick way to check multiple conditions on the input. so for instance. The code stops when either of the three conditions are not satisfied. However, it doesn't produce pretty error messages.
    stopifnot(condition1, condition2, ...)
    
  • Mining R 4.0.0 Changelog for Nuggets of Gold

Lazy evaluation in R functions arguments

R function arguments are lazy — they’re only evaluated if they’re actually used.

  • Example 1. By default, R function arguments are lazy.
f <- function(x) {
  999
}
f(stop("This is an error!"))
#> [1] 999
  • Example 2. If you want to ensure that an argument is evaluated you can use force().
add <- function(x) {
  force(x)
  function(y) x + y
}
adders2 <- lapply(1:10, add)
adders2[[1]](10)
#> [1] 11
adders2[[10]](10)
#> [1] 20
  • Example 3. Default arguments are evaluated inside the function.
f <- function(x = ls()) {
  a <- 1
  x
}

# ls() evaluated inside f:
f()
# [1] "a" "x"

# ls() evaluated in global environment:
f(ls())
# [1] "add"    "adders" "f" 
  • Example 4. Laziness is useful in if statements — the second statement below will be evaluated only if the first is true.
x <- NULL
if (!is.null(x) && x > 0) {

}

Use of functions as arguments

Just Quickly: The unexpected use of functions as arguments

body()

Remove top axis title base plot

Return functions in R

anonymous function

In R, the main difference between a lambda function (also known as an anonymous function) and a regular function is that a lambda function is defined without a name, while a regular function is defined with a name.

  • See Tidyverse page
  • But defining functions to use them only once is kind of overkill. That's why you can use so-called anonymous functions in R. For example, lapply(list(1,2,3), function(x) { x * x })
  • you can use lambda functions with many other functions in R that take a function as an argument. Some examples include sapply, apply, vapply, mapply, Map, Reduce, Filter, and Find. These functions all work in a similar way to lapply by applying a function to elements of a list or vector.
    Reduce(function(x, y) x*y, list(1, 2, 3, 4)) # 24
    
  • purrr anonymous function
  • The new pipe and anonymous function syntax in R 4.1.0
  • Functional programming from Advanced R
  • What are anonymous functions in R.
    > (function(x) x * x)(3)
    [1] 9
    > (\(x) x * x)(3)
    [1] 9

Backtick sign, infix/prefix/postfix operators

The backtick sign ` (not the single quote) refers to functions or variables that have otherwise reserved or illegal names; e.g. '&&', '+', '(', 'for', 'if', etc. See some examples in Advanced R and What do backticks do in R?.

iris %>%  `[[`("Species")

infix operator.

1 + 2    # infix
+ 1 2    # prefix
1 2 +    # postfix

Use with functions like sapply, e.g. sapply(1:5, `+`, 3) .

Error handling and exceptions, tryCatch(), stop(), warning() and message()

  • http://adv-r.had.co.nz/Exceptions-Debugging.html
  • Catch Me If You Can: Exception Handling in R
  • Temporarily disable warning messages
    # Method1: 
    suppressWarnings(expr)
    
    # Method 2:
    <pre>
    defaultW <- getOption("warn") 
    options(warn = -1) 
    [YOUR CODE] 
    options(warn = defaultW)
    
  • try() allows execution to continue even after an error has occurred. You can suppress the message with try(..., silent = TRUE).
    out <- try({
      a <- 1
      b <- "x"
      a + b
    })
    
    elements <- list(1:10, c(-1, 10), c(T, F), letters)
    results <- lapply(elements, log)
    is.error <- function(x) inherits(x, "try-error")
    succeeded <- !sapply(results, is.error)
    
  • tryCatch(): With tryCatch() you map conditions to handlers (like switch()), named functions that are called with the condition as an input. Note that try() is a simplified version of tryCatch().
    tryCatch(expr, ..., finally)
    
    show_condition <- function(code) {
      tryCatch(code,
        error = function(c) "error",
        warning = function(c) "warning",
        message = function(c) "message"
      )
    }
    show_condition(stop("!"))
    #> [1] "error"
    show_condition(warning("?!"))
    #> [1] "warning"
    show_condition(message("?"))
    #> [1] "message"
    show_condition(10)
    #> [1] 10
    

    Below is another snippet from available.packages() function,

    z <- tryCatch(download.file(....), error = identity)
    if (!inherits(z, "error")) STATEMENTS
    
  • The return class from tryCatch() may not be fixed.
    result <- tryCatch({
      # Code that might generate an error or warning
      log(99)
    }, warning = function(w) {
      # Code to handle warnings
      print(paste("Warning:", w))
    }, error = function(e) {
      # Code to handle errors
      print(paste("Error:", e))
    }, finally = {
      # Code to always run, regardless of whether an error or warning occurred
      print("Finished")
    })   
    # character type. But if we remove 'finally', it will be numeric.
    
  • Capture message, warnings and errors from a R function

suppressMessages()

suppressMessages(expression)

List data type

Create an empty list

out <- vector("list", length=3L) # OR out <- list()
for(j in 1:3) out[[j]] <- myfun(j)

outlist <- as.list(seq(nfolds))

Nested list of data frames

An array can only hold data of a single type. read.csv() returns a data frame, which can contain both numerical and character data.

res <- vector("list", 3) 
names(res) <- paste0("m", 1:3)
for (i in seq_along(res)) {
  res[[i]] <- vector("list", 2)  # second-level list with 2 elements
  names(res[[i]]) <- c("fc", "pre")
}

res[["m1"]][["fc"]] <- read.csv()

head(res$m1$fc) # Same as res[["m1"]][["fc"]]

Using $ in R on a List

How to Use Dollar Sign ($) Operator in R

Calling a function given a list of arguments

> args <- list(c(1:10, NA, NA), na.rm = TRUE)
> do.call(mean, args)
[1] 5.5
> mean(c(1:10, NA, NA), na.rm = TRUE)
[1] 5.5

Descend recursively through lists

x[[c(5,3)]] is the same as x[[5]][[3]]. See ?Extract.

Avoid if-else or switch

?plot.stepfun.

y0 <- c(1,2,4,3)
sfun0  <- stepfun(1:3, y0, f = 0)
sfun.2 <- stepfun(1:3, y0, f = .2)
sfun1  <- stepfun(1:3, y0, right = TRUE)

tt <- seq(0, 3, by = 0.1)
op <- par(mfrow = c(2,2))
plot(sfun0); plot(sfun0, xval = tt, add = TRUE, col.hor = "bisque")
plot(sfun.2);plot(sfun.2, xval = tt, add = TRUE, col = "orange") # all colors
plot(sfun1);lines(sfun1, xval = tt, col.hor = "coral")
##-- This is  revealing :
plot(sfun0, verticals = FALSE,
     main = "stepfun(x, y0, f=f)  for f = 0, .2, 1")

for(i in 1:3)
  lines(list(sfun0, sfun.2, stepfun(1:3, y0, f = 1))[[i]], col = i)
legend(2.5, 1.9, paste("f =", c(0, 0.2, 1)), col = 1:3, lty = 1, y.intersp = 1)

par(op)

File:StepfunExample.svg

Open a new Window device

X11() or dev.new()

par()

?par

text size (cex) and font size on main, lab & axis

Examples (default is 1 for each of them):

  • cex.main=0.9
  • cex.sub
  • cex.lab=0.8, font.lab=2 (x/y axis labels)
  • cex.axis=0.8, font.axis=2 (axis/tick text/labels)
  • col.axis="grey50"

An quick example to increase font size (cex.lab, cex.axis, cex.main) and line width (lwd) in a line plot and cex & lwd in the legend.

plot(x=x$mids, y=x$density, type="l", 
     xlab="p-value", ylab="Density", lwd=2, 
     cex.lab=1.5, cex.axis=1.5, 
     cex.main=1.5, main = "")
lines(y$mids, y$density, lty=2, pwd=2)
lines(z$mids, z$density, lty=3, pwd=2)
legend('topright',legend = c('Method A','Method B','Method C'),
       lty=c(2,1,3), lwd=c(2,2,2), cex = 1.5, xjust = 0.5, yjust = 0.5)

ggplot2 case (default font size is 11 points):

  • plot.title
  • plot.subtitle
  • axis.title.x, axis.title.y: (x/y axis labels)
  • axis.text.x & axis.text.y: (axis/tick text/labels)
ggplot(df, aes(x, y)) +
  geom_point() +
  labs(title = "Title", subtitle = "Subtitle", x = "X-axis", y = "Y-axis") +
  theme(plot.title = element_text(size = 20),
        plot.subtitle = element_text(size = 15),
        axis.title.x = element_text(size = 15),
        axis.title.y = element_text(size = 15),
        axis.text.x = element_text(size = 10),
        axis.text.y = element_text(size = 10))

Default font

layout

reset the settings

op <- par(mfrow=c(2,1), mar = c(5,7,4,2) + 0.1) 
....
par(op) # mfrow=c(1,1), mar = c(5,4,4,2) + .1

mtext (margin text) vs title

mgp (axis tick label locations or axis title)

  1. The margin line (in ‘mex’ units) for the axis title, axis labels and axis line. Note that ‘mgp[1]’ affects the axis ‘title’ whereas ‘mgp[2:3]’ affect tick mark labels. The default is ‘c(3, 1, 0)’. If we like to make the axis labels closer to an axis, we can use mgp=c(1.5, .5, 0) for example.
    • the default is c(3,1,0) which specify the margin line for the axis title, axis labels and axis line.
    • the axis title is drawn in the fourth line of the margin starting from the plot region, the axis labels are drawn in the second line and the axis line itself is the first line.
  2. Setting graph margins in R using the par() function and lots of cow milk
  3. Move Axis Label Closer to Plot in Base R (2 Examples)
  4. http://rfunction.com/archives/1302 mgp – A numeric vector of length 3, which sets the axis label locations relative to the edge of the inner plot window. The first value represents the location the labels/axis title (i.e. xlab and ylab in plot), the second the tick-mark labels, and third the tick marks. The default is c(3, 1, 0).

move axis title closer to axis

title(ylab="Within-cluster variance", line=0, 
      cex.lab=1.2, family="Calibri Light")

pch and point shapes

File:R pch.png

See here.

  • Full circle: pch=16
  • Display all possibilities: ggpubr::show_point_shapes()

lty (line type)

File:R lty.png

Line types in R: Ultimate Guide For R Baseplot and ggplot

See here.

ggpubr::show_line_types()

las (label style)

0: The default, parallel to the axis

1: Always horizontal boxplot(y~x, las=1)

2: Perpendicular to the axis

3: Always vertical

oma (outer margin), xpd, common title for two plots, 3 types of regions, multi-panel plots

no.readonly

R语言里par(no.readonly=TURE)括号里面这个参数什么意思?, R-par()

Non-standard fonts in postscript and pdf graphics

https://cran.r-project.org/doc/Rnews/Rnews_2006-2.pdf#page=41


NULL, NA, NaN, Inf

https://tomaztsql.wordpress.com/2018/07/04/r-null-values-null-na-nan-inf/

save()/load() vs saveRDS()/readRDS() vs dput()/dget() vs dump()/source()

  1. saveRDS() can only save one R object while save() does not have this constraint.
  2. saveRDS() doesn’t save the both the object and its name it just saves a representation of the object. As a result, the saved object can be loaded into a named object within R that is different from the name it had when originally serialized. See this post.
x <- 5
saveRDS(x, "myfile.rds")
x2 <- readRDS("myfile.rds")
identical(mod, mod2, ignore.environment = TRUE)

dput: Writes an ASCII text representation of an R object. The object name is not written (unlike dump).

$ data(pbc, package = "survival")
$ names(pbc)
$ dput(names(pbc))
c("id", "time", "status", "trt", "age", "sex", "ascites", "hepato", 
"spiders", "edema", "bili", "chol", "albumin", "copper", "alk.phos", 
"ast", "trig", "platelet", "protime", "stage")

> iris2 <- iris[1:2, ]
> dput(iris2)
structure(list(Sepal.Length = c(5.1, 4.9), Sepal.Width = c(3.5, 
3), Petal.Length = c(1.4, 1.4), Petal.Width = c(0.2, 0.2), Species = structure(c(1L, 
1L), .Label = c("setosa", "versicolor", "virginica"), class = "factor")), row.names = 1:2, class = "data.frame")

User 'verbose = TRUE' in load()

When we use load(), it is helpful to add 'verbose =TRUE' to see what objects get loaded.

What are RDS files anyways

Archive Existing RDS Files

==, all.equal(), identical()

  • ==: exact match
  • all.equal: compare R objects x and y testing ‘near equality’
  • identical: The safe and reliable way to test two objects for being exactly equal.
x <- 1.0; y <- 0.99999999999
all.equal(x, y)
# [1] TRUE
identical(x, y)
# [1] FALSE

Be careful about using "==" to return an index of matches in the case of data with missing values.

R> c(1,2,NA)[c(1,2,NA) == 1]
[1]  1 NA
R> c(1,2,NA)[which(c(1,2,NA) == 1)]
[1] 1

See also the testhat package.

I found a case when I compare two objects where 1 is generated in Linux and the other is generated in macOS that identical() gives FALSE but all.equal() returns TRUE. The difference has a magnitude only e-17.

waldo

diffobj: Compare/Diff R Objects

https://cran.r-project.org/web/packages/diffobj/index.html

testthat

tinytest

tinytest: Lightweight but Feature Complete Unit Testing Framework

ttdo adds support of the 'diffobj' package for 'diff'-style comparison of R objects.

Numerical Pitfall

Numerical pitfalls in computing variance

.1 - .3/3
## [1] 0.00000000000000001388

Sys.getpid()

This can be used to monitor R process memory usage or stop the R process. See this post.

Sys.getenv() & make the script more portable

Replace all the secrets from the script and replace them with Sys.getenv("secretname"). You can save the secrets in an .Renviron file next to the script in the same project.

$ for v in 1 2; do MY=$v Rscript -e "Sys.getenv('MY')"; done
[1] "1"
[1] "2"
$ echo $MY
2

How to write R codes

  • Code smells and feels from R Consortium
    • write simple conditions,
    • handle class properly,
    • return and exit early,
    • polymorphism,
    • switch() [e.g., switch(var, value1=out1, value2=out2, value3=out3). Several examples in glmnet ]
    • case_when(),
    • %||%.
  • 5 Tips for Writing Clean R Code – Leave Your Code Reviewer Commentless
    • Comments
    • Strings
    • Loops
    • Code Sharing
    • Good Programming Practices

How to debug an R code

Debug R

Locale bug (grep did not handle UTF-8 properly PR#16264)

https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=16264

Path length in dir.create() (PR#17206)

https://bugs.r-project.org/bugzilla3/show_bug.cgi?id=17206 (Windows only)

install.package() error, R_LIBS_USER is empty in R 3.4.1 & .libPaths()

R_LIBS_USER=${R_LIBS_USER-'~/R/x86_64-pc-linux-gnu-library/3.4'}
R_LIBS_USER="${HOME}/R/${R_PLATFORM}-library/3.4"

On Mac & R 3.4.0 (it's fine)

> Sys.getenv("R_LIBS_USER")
[1] "~/Library/R/3.4/library"
> .libPaths()
[1] "/Library/Frameworks/R.framework/Versions/3.4/Resources/library"

On Linux & R 3.3.1 (ARM)

> Sys.getenv("R_LIBS_USER")
[1] "~/R/armv7l-unknown-linux-gnueabihf-library/3.3"
> .libPaths()
[1] "/home/$USER/R/armv7l-unknown-linux-gnueabihf-library/3.3"
[2] "/usr/local/lib/R/library"

On Linux & R 3.4.1 (*Problematic*)

> Sys.getenv("R_LIBS_USER")
[1] ""
> .libPaths()
[1] "/usr/local/lib/R/site-library" "/usr/lib/R/site-library"
[3] "/usr/lib/R/library"

I need to specify the lib parameter when I use the install.packages command.

> install.packages("devtools", "~/R/x86_64-pc-linux-gnu-library/3.4")
> library(devtools)
Error in library(devtools) : there is no package called 'devtools'

# Specify lib.loc parameter will not help with the dependency package
> library(devtools, lib.loc = "~/R/x86_64-pc-linux-gnu-library/3.4")
Error: package or namespace load failed for 'devtools':
 .onLoad failed in loadNamespace() for 'devtools', details:
  call: loadNamespace(name)
  error: there is no package called 'withr'

# A solution is to redefine .libPaths
> .libPaths(c("~/R/x86_64-pc-linux-gnu-library/3.4", .libPaths()))
> library(devtools) # Works

A better solution is to specify R_LIBS_USER in ~/.Renviron file or ~/.bash_profile; see ?Startup.

Using external data from within another package

https://logfc.wordpress.com/2017/03/02/using-external-data-from-within-another-package/

How to run R scripts from the command line

https://support.rstudio.com/hc/en-us/articles/218012917-How-to-run-R-scripts-from-the-command-line

How to exit a sourced R script

Decimal point & decimal comma

Countries using Arabic numerals with decimal comma (Austria, Belgium, Brazil France, Germany, Netherlands, Norway, South Africa, Spain, Sweden, ...) https://en.wikipedia.org/wiki/Decimal_mark

setting seed locally (not globally) in R

https://stackoverflow.com/questions/14324096/setting-seed-locally-not-globally-in-r

R's internal C API

https://github.com/hadley/r-internals

cleancall package for C resource cleanup

Resource Cleanup in C and the R API

Random number generator

#include <R.h>

void myunif(){
  GetRNGstate();
  double u = unif_rand();
  PutRNGstate();
  Rprintf("%f\n",u);
}
$ R CMD SHLIB r_rand.c
$ R
R> dyn.load("r_rand.so")
R> set.seed(1)
R> .C("myunif")
0.265509
list()
R> .C("myunif")
0.372124
list()
R> set.seed(1)
R> .C("myunif")
0.265509
list()

Test For Randomness

Different results in Mac and Linux

Random numbers: multivariate normal

Why MASS::mvrnorm() gives different result on Mac and Linux/Windows?

The reason could be the covariance matrix decomposition - and that may be due to the LAPACK/BLAS libraries. See

rle() running length encoding

citation()

citation()
citation("MASS")
toBibtex(citation())

Notes on Citing R and R Packages with examples.

R not responding request to interrupt stop process

R not responding request to interrupt stop process. R is executing (for example) a C / C++ library call that doesn't provide R an opportunity to check for interrupts. It seems to match with the case I'm running (dist() function).

Monitor memory usage

  • x <- rnorm(2^27) will create an object of the size 1GB (2^27*8/2^20=1024 MB).
  • Windows: memory.size(max=TRUE)
  • Linux
    • RStudio: htop -p PID where PID is the process ID of /usr/lib/rstudio/bin/rsession, not /usr/lib/rstudio/bin/rstudio. This is obtained by running x <- rnorm(2*1e8). The object size can be obtained through print(object.size(x), units = "auto"). Note that 1e8*8/2^20 = 762.9395.
    • R: htop -p PID where PID is the process ID of /usr/lib/R/bin/exec/R. Alternatively, use htop -p `pgrep -f /usr/lib/R/bin/exec/R`
    • To find the peak memory usage grep VmPeak /proc/$PID/status
  • mem_used() function from pryr package. It is not correct or useful if I use it to check the value compared to the memory returned by jobload in biowulf. So I cannot use it to see the memory used in running mclapply().
  • peakRAM: Monitor the Total and Peak RAM Used by an Expression or Function
  • Error: protect () : protection stack overflow and ?Memory

References:

Monitor Data

Monitoring Data in R with the lumberjack Package

Pushover

Monitoring Website SSL/TLS Certificate Expiration Times with R, {openssl}, {pushoverr}, and {DT}

pushoverr

Resource

Books

  • Efficient R programming by Colin Gillespie and Robin Lovelace. It works to re-create the html version of the book if we follow their simple instruction in the Appendix. Note that pdf version has advantages of expected output (mathematical notations, tables) over the epub version.
    # R 3.4.1
    .libPaths(c("~/R/x86_64-pc-linux-gnu-library/3.4", .libPaths()))
    setwd("/tmp/efficientR/")
    bookdown::render_book("index.Rmd", output_format = "bookdown::pdf_book")
    # generated pdf file is located _book/_main.pdf
    
    bookdown::render_book("index.Rmd", output_format = "bookdown::epub_book")
    # generated epub file is located _book/_main.epub.
    # This cannot be done in RStudio ("parse_dt" not resolved from current namespace (lubridate))
    # but it is OK to run in an R terminal
    

Videos

Webinar

useR!

R consortium

https://www.youtube.com/channel/UC_R5smHVXRYGhZYDJsnXTwg/featured

Blogs, Tips, Socials, Communities

Bug Tracking System

https://bugs.r-project.org/bugzilla3/ and Search existing bug reports. Remember to select 'All' in the Status drop-down list.

Use sessionInfo().

License

Some Notes on GNU Licenses in R Packages

Why Dash uses the mit license (and not a copyleft gpl license)

Interview questions

  • Does R store matrices in column-major order or row-major order?
    • Matrices are stored in column-major order, which means that elements are arranged and accessed by columns. This is in contrast to languages like Python, where matrices (or arrays) are typically stored in row-major order.
  • Explain the difference between == and === in R. Provide an example to illustrate their use.
    • The == operator is used for testing equality of values in R. It returns TRUE if the values on the left and right sides are equal, otherwise FALSE. The === operator does not exist in base R.
  • What is the purpose of the apply() function in R? How does it differ from the for loop?
    • The apply() function in R is used to apply a function over the margins of an array or matrix. It is often used as an alternative to loops for applying a function to each row or column of a matrix.
  • Describe the concept of factors in R. How are they used in data manipulation and analysis?
    • Factors in R are used to represent categorical data. They are an essential data type for statistical modeling and analysis. Factors store both the unique values that occur in a dataset and the corresponding integer codes used to represent those values.
  • What is the significance
of the attach() and detach() functions in R? When should they be used?
    • A: The attach() function is used to add a data frame to the search path in R, making it easier to access variables within the data frame. The detach() function is used to remove a data frame from the search path, which can help avoid naming conflicts and reduce memory usage.
  • Explain the concept of vectorization in R. How does it impact the performance of R code?
    • Vectorization in R refers to the ability to apply operations to entire vectors or arrays at once, without needing to write explicit loops. This can significantly improve the performance of R code, as it allows operations to be performed in a more efficient, vectorized manner by taking advantage of R's underlying C code.
  • Describe the difference between data.frame and matrix in R. When would you use one over the other?
    • A data.frame in R is a two-dimensional structure that can store different types of data (e.g., numeric, character, factor) in its columns. It is similar to a table in a database.
    • A matrix in R is also a two-dimensional structure, but it can only store elements of the same data type. It is more like a mathematical matrix.
    • You would use a data.frame when you have heterogeneous data (i.e., different types of data) and need to work with it as a dataset. You would use a matrix when you have homogeneous data (i.e., the same type of data) and need to perform matrix operations.
  • What are the benefits of using the dplyr package in R for data manipulation? Provide an example of how you would use dplyr to filter a data frame.
    • The dplyr package provides a set of functions that make it easier to manipulate data frames in R.
    • It uses a syntax that is easy to read and understand, making complex data manipulations more intuitive.
    • To filter a data frame using dplyr, you can use the filter() function. For example, filter(df, column_name == value) would filter df to include only rows where column_name is equal to value.