comment on

This is just so that I can refer to some example code when I tell people to use gnuplot (instead of for example the popular GD module) to draw plots.

use strict; use warnings; use 5.010; 
use IO::Handle;
use File::Temp "tempfile";
my($T,$N) = tempfile("plot-XXXXXXXX", "UNLINK", 1); 
for my $t (100..500) 
        { say $T $t*sin($t*0.1), " ", $t*cos($t*0.1); } 
close $T;
open my $P, "|-", "gnuplot" or die; 
printflush $P qq[
        unset key
        plot "$N" with lines lw 3
]; 
<STDIN>; 
close $P;
__END__
[download]

You need gnuplot installed on your computer to run this. Read the gnuplot manual if you want to control the plot, for example change its appeariance, use dates as one coordinate, or export the plot to an image file. Use empty lines to draw discontinuous line segments.

Update: other posts where I've recommended gnuplot are: Re: perl postscript, Re: Interface to Gnuplot ?, Re^2: Easy plotting ?, Re^3: measuring IN/OUT traffic on your computer, Re: Draw chart (recommended), Re: Matrix magic with Perl + Octave, R or MatLab?, Re: parse a csv file and create array of arrays and then plot the data, Re: Export Plots, Two questions for GD::Graph, Stacked Bar (recommended).

Update: see also other posts about gnuplot: Statistical Graphs with gnuplot and mod_perl, Chart::Gnuplot png format, Re: Intro to plotting with perl.

Update 2011-01-28: added the statement close $T; which fixes a possible bug where the handle $T is not flushed.

In reply to Plot a spiral with gnuplot by ambrus

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Perl: the Markov chain saw
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