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askYesNo Ask a Yes/No Question

Description

askYesNo provides a standard way to ask the user a yes/no question. It provides a way for front-ends to substitute their own dialogs.

Usage

askYesNo(msg, default = TRUE, 
         prompts = getOption("askYesNo", gettext(c("Yes", "No", "Cancel"))), 
         ...)

Arguments

msg	The prompt message for the user.
default	The default response.
prompts	Any of: a character vector containing 3 prompts corresponding to return values of TRUE, FALSE, or NA, or a single character value containing the prompts separated by / characters, or a function to call.
...	Additional parameters, ignored by the default function.

Details

askYesNo will accept case-independent partial matches to the prompts. If no response is given the value of default will be returned; if a non-empty string that doesn't match any of the prompts is entered, an error will be raised.

If a function or single character string naming a function is given for prompts, it will be called as fn(msg = msg, default = default, prompts = prompts, ...). On Windows, the GUI uses the unexported utils:::askYesNoWinDialog function for this purpose.

If strings (or a string such as "Y/N/C") are given as prompts, the choices will be mapped to lowercase for the non-default choices, and left as-is for the default choice.

Value

TRUE for yes, FALSE for no, and NA for cancel.

See Also

readline for more general user input.

Examples

if (interactive())
    askYesNo("Do you want to use askYesNo?")