menu: Menu Interaction Function

Description

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 0.

Usage

menu(choices, graphics = FALSE, title = NULL)

Arguments

choices

a character vector of choices

graphics

a logical indicating whether a graphics menu should be used if available.

title

a character string to be used as the title of the menu. NULL is also accepted.

Value

The number corresponding to the selected item, or 0 if no choice was made.

Details

If graphics = TRUE and a windowing system is available (Windows, macOS or X11 via Tcl/Tk) a listbox widget is used, otherwise a text menu. It is an error to use 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 title is NULL or "".

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

Examples

Run this code

## Not run: ------------------------------------
# switch(menu(c("List letters", "List LETTERS")) + 1,
#        cat("Nothing done\n"), letters, LETTERS)
## ---------------------------------------------

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