R is a language and environment for statistical computing and graphics.
1. R is an integrated suite of software facilities for data manipulation, calculation and graphical display. It includes:
a) An effective data handling and storage facility.
b) A suite of operators for calculations on arrays in particular matrices.
c) A large, coherent, integrated collection of intermediate tools for data analysis.
d) Graphical facilities for data analysis and display either on-screen or on hardcopy.
e) A well-developed, simple and effective programming language which includes conditionals, loops, user defined recursive functions and input and output facilities.
2. R and its libraries implement a wide variety of statistical and graphical techniques, including linear and nonlinear modeling, classical statistical tests, time-series analysis, classification, clustering, and others.
3. R is easily extensible through functions and extensions, and the R community is noted for its active contributions in terms of packages.