On Tue, 21 Oct 2003, Ernie Adorio wrote:
>
> Am using R on a Linux box and am currently writing an interactive R script.
>
> 1. How do I ask a user to press any key to continue ? I used a system call to
> read but this only works if the Enter key is pressed:
> print("Press any key to continue")
> system("read")
You seem over-fond of the system() command! Try
cat("Press enter key to continue\n")
foo <- readLines(stdin(), 1)
In general R does not have a character-by-character interface with a
keyboard.
> 2. How do I get a string input from the user? Would like to see an R function,
> say askget():
>
> delay = askget("Enter delay in seconds")
> system(paste( "sleep ", delay))
cat("Enter delay in seconds:\n")
Delay <- scan("", numeric(1))
Sys.sleep(Delay)
will do it (there are other more elegant ways such as
testit <- function()
{
cat("Enter delay in seconds: ")
Delay <- as.numeric(readLines(stdin(), 1))
if(is.na(Delay)) stop("non-numeric input")
Sys.sleep(Delay)
}
)
--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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