• R is a flexible and powerful open-source implementation of the language S (for statistics) developed by John Chambers and others at Bell Labs.

       Why R?
       Five reasons to learn and use R:

• R is open source and completely free. R community members regularly contribute packages to increase R's functionality.
• R is as good as commercially available statistical packages like SPSS, SAS, and Minitab.
• R has extensive statistical and graphing capabilities. R provides hundreds of built-in statistical functions as well as its own built-in programming language.
• R is used in teaching and performing computational statistics. It is the language of choice for many academics who teach computational statistics.
• Getting help from the R user community is easy. There are readily available online tutorials, data sets, and discussion forums about R.           

       R uses: 

• R combines aspects of functional and object-oriented programming.
• R can use in interactive mode
• It is an interpreted language rather than a compiled one.
• Finding and fixing mistakes is typically much easier in R than in many other languages.

      R Features:-

• Programming language for graphics and statistical computations
• Available freely under the GNU public license
• Used in data mining and statistical analysis
• Included time series analysis, linear and nonlinear modeling among others
• Very active community and package contributions
• Very little programming language knowledge necessary