| % File src/library/utils/man/menu.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2013 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{menu} |
| \alias{menu} |
| \title{Menu Interaction Function} |
| \description{ |
| \code{menu} presents the user with a menu of choices labelled from 1 |
| to the number of choices. To exit without choosing an item one can |
| select \samp{0}. |
| } |
| \usage{ |
| menu(choices, graphics = FALSE, title = NULL) |
| } |
| \arguments{ |
| \item{choices}{a character vector of choices} |
| \item{graphics}{a logical indicating whether a graphics menu should be |
| used if available.} |
| \item{title}{a character string to be used as the title of the menu. |
| \code{NULL} is also accepted.} |
| } |
| \details{ |
| If \code{graphics = TRUE} and a windowing system is available |
| (Windows, macOS or X11 \emph{via} Tcl/Tk) a listbox widget is |
| used, otherwise a text menu. It is an error to use \code{menu} in a |
| non-interactive session. |
| |
| Ten or fewer items will be displayed in a single column, more in |
| multiple columns if possible within the current display width. |
| |
| No title is displayed if \code{title} is \code{NULL} or \code{""}. |
| } |
| \value{ |
| The number corresponding to the selected item, or 0 if no choice was |
| made. |
| } |
| \seealso{ |
| \code{\link{select.list}}, which is used to implement the graphical |
| menu, and allows multiple selections. |
| } |
| \references{ |
| Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) |
| \emph{The New S Language}. |
| Wadsworth & Brooks/Cole. |
| } |
| \examples{ |
| \dontrun{ |
| switch(menu(c("List letters", "List LETTERS")) + 1, |
| cat("Nothing done\n"), letters, LETTERS) |
| } |
| } |
| \keyword{utilities} |
| \keyword{programming} |