R ARTICLE

History of R

R is a programming language for statistical computing and graphics supported by the R Core Team and the R Foundation for Statistical Computing . Created by statisticians Ross Ihaka and Robert Gentleman , R is used among data miners, bioinformaticians and statisticians for data analysis and developing statistical software. Users have created packages to augment the functions of the R language.

R Introduction

What is R?

• R is a language and environment for statistical computing and graphics.
• It is a GNU project which is similar to the S language and environment which was developed at Bell Laboratories 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 environment

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 large, coherent, integrated collection of intermediate tools for data analysis,
• graphical facilities for data analysis and display either on-screen or on hardcopy.

R Syntax

R Command Prompt

• R command prompt by just typing the following command at your command prompt −

        
          $ R
        
      

• This will launch R interpreter and you will get a prompt > where you can start typing your program as follows −

        
          > myString <- "Hello, World!"
          > print ( myString )
          [1] "Hello, World!"
        
      

• R does not support multi-line comments but you can perform a trick which is something as follows −

        
        if(FALSE) {
          
            This is a demo for multi-line comments
            and it should be put inside either a
            single OR double quote"
          
          }

          myString <- "Hello, World!"
        print( myString )
        
      

R Variables

Variable Name -> Validity -> Reason

• var_name% -> Invalid -> Has the character '%'. Only dot(.) and underscore allowed.
• var_name2. -> valid -> Has letters, numbers, dot and underscore
• 2var_name -> invalid -> Starts with a number