data {base} | R Documentation

## Data Sets

### Description

`data` loads a data set or lists (via `show.data`) the available data sets.

### Usage

    data(..., list = character(0), package = .packages(),
         lib.loc = .lib.loc)
    show.data(package = .packages(), lib.loc = .lib.loc)

### 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.
`lib.loc` | a character vector of directory names of R libraries. Defaults to all libraries currently known.

### 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 or `show.data` is called directly, the available data sets are displayed.

If no data sets are specified, `data` calls `show.data`. `show.data` 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.

If `lib.loc` is not specified, the packages are searched for amongst those already loaded, followed by the ``data`' directory (if any) of the current working directory. If `lib.loc` is specified, they 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

`data()` returns a character vector of all data sets specified, an empty character vector 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 preprocess 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'

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