R is a programming language and free software environment for statistical computing and graphics supported by the R Foundation for Statistical Computing. The R language is widely used among statisticians and data miners for developing statistical software and data analysis. Polls, data mining surveys, and studies of scholarly literature databases show substantial increases in popularity; as of September 2020, R ranks 9th in the TIOBE index, a measure of popularity of programming languages.
R is available as a free software project, available under the Free Software Foundation GNU General Public License. It is available on Windows, MacOS, and is available or can be complied for many Unix/Linux platforms.
The base packages of R, as downloaded and installed in the link below, is a command line interface (CLI) based programming environment. Most users of R will also install R Studio (see the other tab) which provides an Integrated Development Environment (IDE) for R.
R Studio comes in a couple different flavors: Desktop and Server. Desktop versions run on a PC (Windows, Macintosh, or Linux) and Server versions run on a server - the user connects to the server using a web browser. Both Desktop and Server versions come in the Open Source and Professional versions. The Open Source versions are free, but do not include professional support. Pro versions include a commercial license, which includes support from R Studio.
Typically, for personal use, the Open Source Desktop version is used.
Note: R must be installed separately from R Studio.