ABSTRACT
Base R and the recommended extension packages (installed by default) include many functions for manipulating data. The R distribution supplies a complete set of functions and operators that allow all the usual data manipulation operations. These functions have stable and well described behaviour. Their design is based on a specific compromise between performance, easy of use and consistency. Alternatives defined in contributed packages differ in their design, based on a different compromise solutions. In this chapter some of these extensions are introduced and their features compared to those provided by base R.
