R help - Oct 2003 - interactive prompts

On 10/21/03 14:47, 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")
>
>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))
readline()

-- 
Jonathan Baron, Professor of Psychology, University of Pennsylvania
Home page:            http://www.sas.upenn.edu/~baron
R page:               http://finzi.psych.upenn.edu/

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")
  par(ask = TRUE)
will do what you want.

-- 
Cheers,

Kevin

---------------------------------------------------------------
Ko-Kang Kevin Wang
Master of Science (MSc) Student
SLC Tutor and Lab Demonstrator
Department of Statistics
University of Auckland
New Zealand
Homepage: http://www.stat.auckland.ac.nz/~kwan022
Ph: 373-7599
    x88475 (City)
    x88480 (Tamaki)

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,                  ripley at stats.ox.ac.uk
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

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")
Maybe just readline("Press Enter to continue")? Why give the user the 
choice?
> 
> 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))
readline(), but the return value needs to be cast from a character vector
of length one to what you need, because you can't depend on the user to
only give admissible values. Although your example is just that,
Sys.sleep()  gets you there directly.

> 
> TIA,
> 
> Ernie Adorio
> Math Department
> University of the Philippines
> Diliman, Quezon City
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> 
-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand at nhh.no

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")

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))

TIA,

Ernie Adorio
Math Department
University of the Philippines
Diliman, Quezon City