R organizes documentation in terms of packages and functions. Documentation comes with each package you download and install.
R Package Documentation
All R functions, dataset and other objects are stored in packages. A package's contents, including its documentation, is available only after it is loaded. To see a list of installed R packages type:
> library()
This should produce a list such as follows:
Packages in library 'C:/PROGRA~1/R/rw2011/library': base The R Base Package boot Bootstrap R (S-Plus) Functions (Canty) class Functions for Classification cluster Cluster Analysis Extended Rousseeuw et al. datasets The R Datasets Package graphics The R Graphics Package ...
To load a package, use library("package_name"):
> library(graphics)
To view the documentation of a package, we use library(help="package_name") or help(package="package_name"):
> library(help=graphics)
or
> help(package=graphics)
This should produce a list such a follows:
Information on package 'graphics'
Description:
Package: graphics
Version: 2.1.1
Priority: base
Title: The R Graphics Package
Maintainer: R Core Team
Description: R functions for base graphics
Depends: grDevices
License: GPL Version 2 or later.
Built: R 2.1.1; ; 2005-06-21 08:25:36; windows
Index:
abline Add a Straight Line to a Plot
arrows Add Arrows to a Plot
assocplot Association Plots
...
R Function Documentation
The package documentation list all the functions of a package along with one line descriptions of the functions. A more detailed documentation is also available for each function. To access it, you need to use help(function_name):
> help(arrows)
Navigable Help System
A HTML based help system is also available. To use this you have to type the following command:
> help.start()
The help system is very user-friendly and contains all the information you can access with the help command and more.