Documentation

Usage

help(topic, offline = FALSE, package = c(.packages(), .Autoloaded),
     lib.loc = .lib.loc, verbose = .Options$verbose,
      htmlhelp = .Options$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.

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

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.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'

[Package Contents]