The R Programming Environment
Richard E. Plant · 2018
R is an open source program, which means, among other things, that it is freely distributed and that in addition to the executable files, the source code is made available to all. Unlike some programming environments and statistical software packages, R is designed to be used interactively. One of the great things about a programming environment like R, as opposed to a menu-driven application, is that code can be reused after slight modification. R supports functional programming, which permits the programmer to replace many instances of looping and branching with applications of a function or operation. The R programming environment, both in its base and contributed packages, provides an incredibly powerful and flexible array of tools for constructing graphical images. Some programming languages, such as C++ and Fortran, require that the size of an array always be declared before that array has values assigned to it.