available.packages returns a matrix of details corresponding to
packages currently available at one or more repositories. The
current list of packages is downloaded over the internet (or copied
from a local mirror).
available.packages(contriburl = contrib.url(repos, type), method,
fields = NULL, type = getOption("pkgType"),
filters = NULL, repos = getOption("repos"))URL(s) of the contrib sections of the repositories.
Specify this argument only if your repository mirror is incomplete,
e.g., because you burned only the contrib section on a CD.
download method, see download.file.
character string, indicate which type of packages: see
install.packages.
If type = "both" this will use the source repository.
a character vector giving the fields to extract from
the PACKAGES file(s) in addition to the default ones, or
NULL (default). Unavailable fields result in NA
values.
a character vector or list or NULL (default). See ‘Details’.
character vector, the base URL(s) of the repositories to use.
A matrix with one row per package, row names the package names and
column names including "Package", "Version",
"Priority", "Depends", "Imports",
"LinkingTo", "Suggests", "Enhances",
"File" and "Repository". Additional columns can be
specified using the fields argument.
Where provided by the repository, fields "OS_type",
"License", "License_is_FOSS",
"License_restricts_use", "Archs", "MD5sum" and
"NeedsCompilation" are reported for use by the filters and
package management tools, including install.packages.
The list of packages is either copied from a local mirror (specified by a
file:// URI) or downloaded. If downloaded, the list is cached
for the R session in a per-repository file in tempdir()
with a name like
repos_http%3a%2f%2fcran.r-project.org%2fsrc%2fcontrib.rds
By default, the return value includes only packages whose version and OS requirements are met by the running version of R, and only gives information on the latest versions of packages.
Argument filters can be used to select which of the packages on the
repositories are reported. It is called with its default value
(NULL) by functions such as install.packages: this value
corresponds to getOption("available_packages_filters")
and to c("R_version", "OS_type", "subarch", "duplicates") if
that is unset or set to NULL.
The built-in filters are
"R_version"Exclude packages whose R version requirements are not met.
"OS_type"Exclude packages whose OS requirement is incompatible with this version of R: that is exclude Windows-only packages on a Unix-alike platform and vice versa.
"subarch"For binary packages, exclude those with compiled code that is not available for the current sub-architecture, e.g.exclude packages only compiled for 32-bit Windows on a 64-bit Windows R.
"duplicates"Only report the latest version where more
than one version is available, and only report the first-named
repository (in contriburl) with the latest version if that
is in more than one repository.
"license/FOSS"Include only packages for which installation can proceed solely based on packages which can be verified as Free or Open Source Software (FOSS, e.g., https://en.wikipedia.org/wiki/FOSS) employing the available license specifications. Thus both the package and any packages that it depends on to load need to be known to be FOSS.
Note that this does depend on the repository supplying license information.
"license/restricts_use"Include only packages for which installation can proceed solely based on packages which are known not to restrict use.
"CRAN"Use CRAN versions in preference to versions
from other repositories (even if these have a higher version
number). This needs to be applied before the default
"duplicates" filter, so cannot be used with
add = TRUE.
If all the filters are from this set, then they can be specified as a
character vector; otherwise filters should be a list with
elements which are character strings, user-defined functions or
add = TRUE (see below).
User-defined filters are functions which take a single argument, a
matrix of the form returned by available.packages, and
return a matrix consisting of a subset of the rows of the argument.
The special ‘filter’ add = TRUE appends the other
elements of the filter list to the default filters.
install.packages, download.packages,
contrib.url.
The ‘R Installation and Administration’ manual for how to set up a repository.
# NOT RUN {
## Restrict install.packages() (etc) to known-to-be-FOSS packages
options(available_packages_filters =
c("R_version", "OS_type", "subarch", "duplicates", "license/FOSS"))
## or
options(available_packages_filters = list(add = TRUE, "license/FOSS"))
## Give priority to released versions on CRAN, rather than development
## versions on Omegahat, R-Forge etc.
options(available_packages_filters =
c("R_version", "OS_type", "subarch", "CRAN", "duplicates"))
# }
Run the code above in your browser using DataLab