evaluating keystroke

Hi all,

is it possible that a R function wait for a keystroke (as the demo()
function do) and evaluate the pressed key?

Not really.  In general you need to hit Return to get any input
into R, and the readline() function is one way to do this.  The
platform-specific input routines wait for a complete line (indicated by
hitting Return) before passing the line onto R.

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 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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Sven Garbade <garbade at psy.uni-muenchen.de> writes:

Hi all,

is it possible that a R function wait for a keystroke (as the demo()
function do) and evaluate the pressed key?

The only function I know is readline() which will allow up to 32
characters to be read from the console. Use subst() to query the
returned string. See help(readline) for details.

Mark


--
Mark Myatt


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On the question of evaluating keystrokes:

I often plot subsets of data to get a sense of what I'm looking for. I
generally run a for loop with the specification par(ask=TRUE) after each
plot command, so that I can take time to look over the data before going
on to the next plot by pressing RETURN.B

Would it be possible to use readline() in such a command sequence to write
a comment about each plot before going on to the next? This would
certainly help me take quicker and better notes when examining data, and
might even allow me to use R in a perception/classification experiment.

Thanks,

David

S. David White
sdavidwhite at bigfoot.com
Columbus, Ohio

%Sven Garbade <garbade at psy.uni-muenchen.de> writes:
%>Hi all,
%>
%>is it possible that a R function wait for a keystroke (as the demo()
%>function do) and evaluate the pressed key?
%
%The only function I know is readline() which will allow up to 32
%characters to be read from the console. Use subst() to query the
%returned string. See help(readline) for details.
%
%Mark
%
%
%--
%Mark Myatt
%
%
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%r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html
%Send "info", "help", or "[un]subscribe"
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%

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David White <dwhite at ling.ohio-state.edu> writes:

On the question of evaluating keystrokes:

I often plot subsets of data to get a sense of what I'm looking for. I
generally run a for loop with the specification par(ask=TRUE) after each
plot command, so that I can take time to look over the data before going
on to the next plot by pressing RETURN.B

Would it be possible to use readline() in such a command sequence to write
a comment about each plot before going on to the next? This would
certainly help me take quicker and better notes when examining data, and
might even allow me to use R in a perception/classification experiment.

Something like:

        comments <- vector(mode = "character")
        data(volcano)
        for(i in 1:(dim(volcano)[2] - 1))
          {
          plot(volcano[ ,i], volcano[ ,i+1], main = paste("Plot ", i))
          comments[i] <- readline("Comments : ")
          }

Should do the trick.

Mark


--
Mark Myatt


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