readline {base}

R Documentation

Read a Line from the Terminal

Description

readline reads a line from the terminal (in interactive use).

Usage

readline(prompt = "")

Arguments

prompt

the string printed when prompting the user for input. Should usually end with a space " ".

Details

The prompt string will be truncated to a maximum allowed length, normally 256 chars (but can be changed in the source code).

This can only be used in an interactive session.

Value

A character vector of length one. Both leading and trailing spaces and tabs are stripped from the result.

In non-interactive use the result is as if the response was RETURN and the value is "".

See Also

readLines for reading text lines from connections, including files.

Examples

Run examples

fun <- function() {
  ANSWER <- readline("Are you a satisfied R user? ")
  ## a better version would check the answer less cursorily, and
  ## perhaps re-prompt
  if (substr(ANSWER, 1, 1) == "n")
    cat("This is impossible.  YOU LIED!\n")
  else
    cat("I knew it.\n")
}
if(interactive()) fun()

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