data                  package:base                  R Documentation

Data Sets

Description:

     Loads specified data sets, or list the available data sets.

Usage:

     data(..., list = character(0), package = .packages(),
          lib.loc = NULL, verbose = getOption("verbose"))

Arguments:

     ...: a sequence of names or character strings.

    list: a character vector.

 package: a name or character vector giving the packages to look into
          for data sets.  By default, all packages in the search path
          are used, then the `data' directory (if present) of the
          current working directory.

 lib.loc: a character vector of directory names of R libraries, or
          `NULL'.  The default value of `NULL' corresponds to all
          libraries currently known.  If the default is used, the
          loaded packages are searched before the libraries.

 verbose: a logical.  If `TRUE', additional diagnostics are printed.

Details:

     Currently, four formats of data files are supported:

        1.  files ending `.RData' or `.rda' are `load()'ed.

        2.  files ending `.R' or `.r' are `source()'d in, with the R
           working directory changed temporarily to the directory
           containing the respective file.

        3.  files ending `.tab' or `.txt' are read using
           `read.table(..., header = TRUE)', and hence result in a data
           frame.

        4.  files ending `.csv' are read using `read.table(..., header
           = TRUE, sep = ";")', and also result in a data frame.

     The data sets to be loaded can be specified as a sequence of names
     or character strings, or as the character vector `list', or as
     both.

     If no data sets are specified, `data' lists the available data
     sets.  It looks for a file `00Index' in a `data' directory of each
     specified package, and uses these files to prepare a listing. If
     there is a `data' area but no index a warning is given: such
     packages are incomplete.  The information about available data
     sets is returned in an object of class `"packageIQR"'.  The
     structure of this class is experimental.  In earlier versions of
     R, an empty character vector was returned along with listing
     available data sets.

     If `lib.loc' is not specified,  the datasets are searched for
     amongst those packages already loaded, followed by the `data'
     directory (if any) of the current working directory and then
     packages in the specified libraries.  If `lib.loc' is specified,
     packages are searched for in the specified libraries, even if they
     are already loaded from another library.

     To just look in the `data' directory of the current working
     directory, set `package = NULL'.

Value:

     a character vector of all data sets specified, or information
     about all available data sets in an object of class `"packageIQR"'
     if none were specified.

Note:

     The data files can be many small files.  On some file systems it
     is desirable to save space, and the files in the `data' directory
     of an installed package can be zipped up as a zip archive
     `Rdata.zip'.  You will need to provide a single-column file
     `filelist' of file names in that directory.

     One can take advantage of the search order and the fact that a
     `.R' file will change directory.  If raw data are stored in
     `mydata.txt' then one can set up `mydata.R' to read `mydata.txt'
     and pre-process it, e.g. using `transform'. For instance one can
     convert numeric vectors to factors with the appropriate labels. 
     Thus, the `.R' file can effectively contain a metadata
     specification for the plaintext formats.

See Also:

     `help' for obtaining documentation on data sets.

Examples:

     data()                      # list all available data sets
     data(package = base)        # list the data sets in the base package
     data(USArrests, "VADeaths") # load the data sets `USArrests' and `VADeaths'
     help(USArrests)             # give information on data set `USArrests'

