1 Why R?

1.1 What is R?

R is a number of things, simultaneously. Depending on who is being asked, R is:

A software package
A programming language
A toolkit for developing statistical and analytical tools
An extensive library of statistical and mathematical software and algorithms
A scripting language
much, much more

1.2 Why use R?

R is cross-platform and runs on Windows, Mac, and Linux (as well as more obscure systems).
R provides a vast number of useful statistical tools, many of which have been painstakingly tested.
R produces publication-quality graphics in a variety of formats.
R plays well with FORTRAN, C, and scripts in many languages.
R scales, making it useful for small and large projects. It is NOT Excel.
R does not have a meaningfully useful graphical user interface (GUI).

I can develop code for analysis on my Mac laptop. I can then install the same code on our 20k core cluster and run it in parallel on 100 samples, monitor the process, and then update a database (for example) with R when complete.

1.3 Why not use R?

R cannot do everything.
R is not always the “best” tool for the job.
R will not hold your hand. Often, it will slap your hand instead.
The documentation can be opaque (but there is documentation).
R can drive you crazy (on a good day) or age you prematurely (on a bad one).
Finding the right package to do the job you want to do can be challenging; worse, some contributed packages are unreliable.]{}
R does not have a meaningfully useful graphical user interface (GUI).

1.4 R License and the Open Source Ideal

R is free (yes, totally free!) and distributed under GNU license. In particular, this license allows one to:

Download the source code
Modify the source code to your heart’s content
Distribute the modified source code and even charge money for it, but you must distribute the modified source code under the original GNU license]{}

This license means that R will always be available, will always be open source, and can grow organically without constraint.

Background