R is a language and environment for statistical computing and graphics. R is an integrated suite of software facilities for data manipulation, calculation and graphical display. It includes * an effective data handling and storage facility, * a suite of operators for calculations on arrays, in particular matrices, * a large, coherent, integrated collection of intermediate tools for data analysis, * graphical facilities for data analysis and display either on-screen or on hardcopy, and *a well-developed, simple and effective programming language which includes conditionals, loops, user-defined recursive functions and input and output facilities. R is a GNU project which is similar to the S language and environment which was developed at Bell Laboratories (formerly AT&T, now Lucent Technologies) by John Chambers and colleagues. R can be considered as a different implementation of S. There are some important differences, but much code written for S runs unaltered under R. R provides a wide variety of statistical (linear and nonlinear modelling, classical statistical tests, time-series analysis, classification, clustering, …) and graphical techniques, and is highly extensible. The S language is often the vehicle of choice for research in statistical methodology, and R provides an Open Source route to participation in that activity. One of R’s strengths is the ease with which well-designed publication-quality plots can be produced, including mathematical symbols and formulae where needed. Great care has been taken over the defaults for the minor design choices in graphics, but the user retains full control. R is available as Free Software under the terms of the Free Software Foundation’s GNU General Public License in source code form. It compiles and runs on a wide variety of UNIX platforms and similar systems (including FreeBSD and Linux), Windows and MacOS.
