You have not told us your version of R. In earlier versions of R
readline() reads a line from the script (and input buffering affects
which line: a number of packages fail their example checks on some
platforms because of this). In R-devel it returns "" immediately.
To make this work you need to use Rscript, which distinguishes stdin()
and "stdin". Try out
% Rscript foo.R
where foo.R is
message("a")
invisible(readLines("stdin", n=1))
message("b")
and see ?stdin and ?file for why it works.
On Fri, 5 Feb 2010, Jonne Zutt wrote:
Dear all,
I've found this nice code fragment on the web
(from Jan T. Kim if I'm correct):
hitReturn <- function(msg)
{
invisible(readline(sprintf("%s -- hit return", msg)));
}
But it does not seem to work in non-interactive mode
( I mean, when I start a script like this: R --vanilla < script.R )
It simply continues, I guess the stdin is not connected?
Does somebody know how to make it work.
My script plots a few graphs (in X11 windows) and I don't want them to
disappear immediately.
A Sys.sleep(infinite) would probably work, but I thought there might
be a better solution?
Thanks,
Jonne.
--
Brian D. Ripley, rip...@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
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