R: Ask a Yes/No Question

askYesNo {utils} | R Documentation

## 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?")

[Package utils version 3.5.1 Index]