zpackages {base} | R Documentation |
Listing of Packages
Description
.packages
returns information about package availability.
Usage
.packages(all.available = FALSE, lib.loc = NULL)
Arguments
all.available |
logical; if |
lib.loc |
a character vector describing the location of R
library trees to search through, or |
Details
.packages()
returns the names of the currently
attached packages invisibly whereas
.packages(all.available = TRUE)
gives (visibly) all
packages available in the library location path lib.loc
.
For a package to be regarded as being ‘available’ it must have valid
metadata (and hence be an installed package). However, this will
report a package as available if the metadata does not match the
directory name: use find.package
to confirm that the
metadata match or installed.packages
for a much slower
but more comprehensive check of ‘available’ packages.
Value
A character vector of package base names, invisible unless
all.available = TRUE
.
Note
.packages(all.available = TRUE)
is not a way to find out if a
small number of packages are available for use: not only is it
expensive when thousands of packages are installed, it is an
incomplete test. See the help for find.package
for why
require
should be used.
Author(s)
R core;
Guido Masarotto for the all.available = TRUE
part of
.packages
.
See Also
library
, .libPaths
,
installed.packages
.
Examples
(.packages()) # maybe just "base"
.packages(all.available = TRUE) # return all available as character vector
require(splines)
(.packages()) # "splines", too
detach("package:splines")