| libPaths {base} | R Documentation |
Search Paths for Packages
Description
.libPaths gets/sets the library trees within which packages are
looked for.
Usage
.libPaths(new, include.site = TRUE)
.Library
.Library.site
Arguments
new |
a character vector with the locations of R library
trees. Tilde expansion ( |
include.site |
a logical value indicating whether the value of
|
Details
.Library is a character string giving the location of the
default library, the ‘library’ subdirectory of R_HOME.
.Library.site is a (possibly empty) character vector giving the
locations of the site libraries.
.libPaths is used for getting or setting the library trees that R
knows about and hence uses when looking for packages (the library search
path). If called with argument new, by default, the library search
path is set to the existing directories in unique(c(new,
.Library.site, .Library)) and this is returned. If include.site
is FALSE when the new argument is set, .Library.site
is not added to the new library search path. If called without the
new argument, a character vector with the currently active library
trees is returned.
How paths in new with a trailing slash are treated is
OS-dependent. On a POSIX filesystem existing directories can usually
be specified with a trailing slash. On Windows filepaths with a
trailing slash (or backslash) are invalid and existing directories
specified with a trailing slash may not be added to the library search path.
At startup, the library search path is initialized from the
environment variables R_LIBS, R_LIBS_USER and
R_LIBS_SITE, which if set should give lists of directories where
R library trees are rooted, colon-separated on Unix-alike systems and
semicolon-separated on Windows. For the latter two, a value of
NULL indicates an empty list of directories. (Note that as from
R 4.2.0, both are set by R start-up code if not already set or empty
so can be interrogated from an R session to find their defaults:
in earlier versions this was true only for R_LIBS_USER.)
First, .Library.site is initialized from R_LIBS_SITE. If
this is unset or empty, the ‘site-library’ subdirectory of
R_HOME is used. Only directories which exist at the time of
initialization are retained. Then, .libPaths() is called with
the combination of the directories given by R_LIBS and
R_LIBS_USER. By default R_LIBS is unset, and if
R_LIBS_USER is unset or empty, it is set to directory
‘R/R.version$platform-library/x.y’ of the home
directory on Unix-alike systems (or
‘Library/R/m/x.y/library’ for CRAN macOS builds, with
m Sys.info()["machine"]) and
‘R/win-library/x.y’ subdirectory of LOCALAPPDATA on
Windows, for R x.y.z.
Both R_LIBS_USER and R_LIBS_SITE feature possible expansion of specifiers for R-version-specific information as part of the startup process. The possible conversion specifiers all start with a ‘%’ and are followed by a single letter (use ‘%%’ to obtain ‘%’), with currently available conversion specifications as follows:
- ‘%V’
R version number including the patch level (e.g., ‘2.5.0’).
- ‘%v’
R version number excluding the patch level (e.g., ‘2.5’).
- ‘%p’
the platform for which R was built, the value of
R.version$platform.- ‘%o’
the underlying operating system, the value of
R.version$os.- ‘%a’
the architecture (CPU) R was built on/for, the value of
R.version$arch.
(See version for details on R version information.)
In addition, ‘%U’ and ‘%S’ expand to the R defaults for,
respectively, R_LIBS_USER and R_LIBS_SITE.
Function .libPaths always uses the values of .Library
and .Library.site in the base namespace. .Library.site
can be set by the site in ‘Rprofile.site’, which should be
followed by a call to .libPaths(.libPaths()) to make use of the
updated value.
For consistency, the paths are always normalized by
normalizePath(winslash = "/").
LOCALAPPDATA (usually C:\Users\username\AppData\Local) on
Windows is a hidden directory and may not be viewed by some software. It
may be opened by shell.exec(Sys.getenv("LOCALAPPDATA")).
Value
A character vector of file paths.
References
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
See Also
Examples
.libPaths() # all library trees R knows about