help {base} | R Documentation

## Documentation

### Description

These functions provide access to documentation. Documentation on a topic with name `name` (typically, an R object or a data set) can be printed with either `help(name)` or `?name`.

### Usage

    help(topic, offline = FALSE, package = .packages()
         lib.loc = .lib.loc, verbose = getOption("verbose"),
         htmlhelp = getOption("htmlhelp"))
    ?topic

### Arguments

`topic` | a name or character string on which documentation is sought (but not a variable containing a character string!).
`offline` | a logical indicating whether documentation should be displayed on-line to the screen (the default) or hardcopy of it should be produced.
`package` | a name or character vector giving the packages to look into for documentation. 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.
`verbose` | logical; if `TRUE`, the file name is reported.
`htmlhelp` | logical (or `NULL`). If `TRUE` (which is the default after `help.start` has been called), the HTML version of the help will be shown in a browser.

### Details

In the case of unary and binary operators and control-flow special forms, the name may need to be quoted.

If `offline` is `TRUE`, hardcopy of the documentation is produced by running the LaTeX version of the help page through `latex` (note that LaTeX 2e is needed) and `dvips`. Depending on your `dvips` configuration, hardcopy will be sent to the printer or saved in a file. If the programs are in non-standard locations and hence were not found at compile time, you can either set the options `latexcmd` and `dvipscmd`, or the environment variables `R_LATEXCMD` and `R_DVIPSCMD` appropriately. The appearance of the output can be customized through a file ``Rhelp.cfg`' somewhere in your LaTeX search path.

### Note

You will only get help for R objects in your `search()` path, i.e., `help(dist)` will only work after `library(mva)`. To look in all the packages in all the current libraries, use `help(topic, package=.packages(all=T), lib.loc=.lib.loc)`

The help files can be many small files. On some file systems it is desirable to save space, and the text files in the ``help`' directory of an installed package can be zipped up as a zip archive ``Rhelp.zip`'. Ensure the files ``AnIndex`' and ``00Titles`' remain un-zipped. Similarly, all the files in the ``latex`' directory can be zipped to ``Rhelp.zip`'.

### See Also

`help.search()` for finding help pages on a ``vague'' topic. `help.start()` which opens the HTML version of the R Manual; `library()` for listing available packages and the user-level objects they contain; `data()` for listing available data sets; `methods()`.

See `prompt()` to get a prototype for writing `help` pages of private packages.

### Examples

    help()
    help(help)              # the same

    help(lapply)
    ?lapply                 # the same

    help("for")             # or ?"for", but the quotes are needed
    ?"+"

    help(package = stepfun) # get help even when it's not present

    data()                  # list all available data sets
    ?women                  # information about data set "women"

    topi <- "women"
    help(topi) ##--> Error: No documentation for `topi'

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