installed.packages           package:utils           R Documentation

Find Installed Packages

Description:

     Find (or retrieve) details of all packages installed in the
     specified libraries.

Usage:

     installed.packages(lib.loc = NULL, priority = NULL,
                        noCache = FALSE, fields = NULL)

Arguments:

 lib.loc: character vector describing the location of R library trees
          to search through. 

priority: character vector or 'NULL' (default).  If non-null, used to
          select packages; '"high"' is equivalent to 'c("base",
          "recommended")'.  To select all packages without an assigned
          priority use 'priority = "NA"'. 

 noCache: Do not use cached information.

  fields: a character vector giving the fields to extract from each
          package's 'DESCRIPTION' file in addition to the default ones,
          or 'NULL' (default).  Unavailable fields result in 'NA'
          values.

Details:

     'installed.packages' scans the 'DESCRIPTION' files of each package
     found along 'lib.loc' and returns a matrix of package names,
     library paths and version numbers.

     *Note:* this works with package names, not bundle names, and for
     versioned installs with the name under which the package is
     installed, in the style 'mypkg_1.3-7'.

     The information found is cached (by library) for the R session and
     specified 'fields' argument, and updated only if the top-level
     library directory has been altered, for example by installing or
     removing a package.  If the cached information becomes confused,
     it can be refreshed by running 'installed.packages(noCache =
     TRUE)'.

Value:

     A matrix with one row per package, row names the package names and
     column names '"Package"', '"LibPath"', '"Version"', '"Priority"',
     '"Bundle"', '"Contains"', '"Depends"', '"Suggests"', '"Imports"'
     and '"Built"' (the R version the package was built under).
     Additional columns can be specified using the 'fields' argument.

See Also:

     'update.packages', 'INSTALL', 'REMOVE'.

Examples:

     str(ip <- installed.packages(priority = "high"))
     ip[, c(1,3:5)]
     plic <- installed.packages(priority = "high", fields="License")
     ## what licenses are there:
     table( plic[,"License"] )

