.libPaths
gets/sets the library trees within which packages are
looked for.
.libPaths(new)
.Library
.Library.site
path.expand
) is done, and if
any element contains one of *?[
, globbing is done where
supported by the platform: see Sys.glob
..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, by default the site-library
subdirectory of R_HOME (which may not exist).
.libPaths
is used for getting or setting the library trees that
R knows about (and hence uses when looking for packages). If called
with argument new
, the library search path is set to
the existing directories in unique(c(new, .Library.site, .Library))
and this is returned. If given no argument, a character vector with
the currently active library trees is returned.
How paths 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 so will never be added
to the library search path.
unix The library search path is initialized at startup from the environment variable R_LIBS (which should be a colon-separated list of directories at which R library trees are rooted) followed by those in environment variable R_LIBS_USER. Only directories which exist at the time will be included.
By default R_LIBS is unset, and R_LIBS_USER is set to directory R/R.version$platform-library/x.y of the home directory (or Library/R/x.y/library for CRAN OS X builds), for R x.y.z.
.Library.site
can be set via the environment variable
R_LIBS_SITE (as a non-empty colon-separated list of library trees).
windows
The library search path is initialized at startup from the environment
variable R_LIBS (which should be a semicolon-separated list of
directories at which R library trees are rooted) followed by those in
environment variable R_LIBS_USER. Only directories which exist
at the time will be included.
By default R_LIBS is unset, and R_LIBS_USER is set to subdirectory R/win-library/x.y of the home directory, for R x.y.z.
.Library.site
can be set via the environment variable
R_LIBS_SITE (as a non-empty semicolon-separated list of library trees).
Both R_LIBS_USER and R_LIBS_SITE feature possible expansion of specifiers for R version specific information as part of the startup process. The possible conversion specifiers all start with a % and are followed by a single letter (use %% to obtain %), with currently available conversion specifications as follows:
R.version$platform
.
R.version$os
.
R.version$arch
.
(See version
for details on R version information.)
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 = "/")
.
library
.libPaths() # all library trees R knows about
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