library(name, help = NULL, lib.loc = .lib.loc, character.only = FALSE, logical.return = FALSE) require(name, quietly = FALSE) provide(name) library.dynam(chname) .packages() .lib.loc .Library .Provided
|a character vector describing the location of R library trees to search through.|
a logical indicating whether |
|a character string naming a shared library to load|
require(name)both load the package with name
requireis designed for use inside other functions; it returns
FALSEand optionally gives a warning, rather than giving an error, if the package does not exist. Both functions check and update the list of currently loaded packages and do not reload code that is already loaded.
requirealso checks the list
provide allows code to register services that it provides. The
argument is stored in the list
FALSE if the name was already present in
.Provided or among the packages in
search(). The main
provide is when multiple packages share code. This is
most likely when the code implements features present in S(-PLUS) but
not in R. For example, the spline functions
so on are not included in the R distribution. A package containing
these functions can use
provide(splines) to register this fact.
Another package that needs the functions can execute
require(splines) rather than
library(splines) to load
the spline package only if their functionality is not already available.
library is called with no argument, it gives a list of all
library(help = name) prints information on
name, typically by listing the most important user
level objects it contains.
library.dynam loads the specified (shared) object file if it
has not been loaded already. It is designed to be used inside a
package rather than at the command line. The system-specific
extension for shared libraries (e.g., ``.so'' on Unix systems) should
not be added.
.packages() returns the ``base names'' of the currently attached
.Library is a character string giving the location of the
default library, the ``library'' subdirectory of
.lib.loc is a character vector with the locations of all
library trees that R should use. It is initialized at startup from
the environment variable
RLIBS, which should be a
colon-separated list of directories at which R library trees are
libraryreturns the list of loaded packages (or
requirereturns a logical indicating whether the required package is available.
A package consists of a subdirectory containing a `TITLE' and `INDEX' file, and subdirectories `R', `man' and optionally `src', `src-c', `data', and `exec'.
The `TITLE' file contains a line giving the name of the package and a brief description. `INDEX' contains a line for each sufficiently interesting object in the package, giving its name and a description (functions such as print methods not usually called explicitly might not be included).
The `R' subdirectory contains R code files with names beginning
with lowercase letters. One of these files should use
library.dynam() to load any necessary compiled code.
The `man' subdirectory should contain R documentation files for the objects in the package.
Source and a Makefile for the compiled code is in `src', and a
pure C version of the source should be in `src-c'. In the common
case when all the source is in C it may be convenient to make one of
these directories a symbolic link to the other. The Makefile will be
passed various machine-dependent compile and link flags, examples of
which can be seen in the
The `data' subdirectory is for additional data files the package
makes available for loading using
data(). Note that (at least
currently) all such files are in fact R code files, and must have the
Finally, `exec' could contain executables, typically (shell or Perl) scripts, the package needs. Note that this mechanism currently only is experimental.
R INSTALL pkg, where
pkgis the directory containing the package. If you want to install into the library tree
libinstead of the default one, use
R INSTALL pkg lib.
To remove the package
pkg from the default library or the
R REMOVE pkg or
R REMOVE pkg lib,
library() # list all available packages library(lib = .Library) # list all packages in the default library library(help = eda) # documentation on package "eda" library(eda) # load package "eda" require(eda) # the same require(nonexistent) # FALSE