qi has asked for the wisdom of the Perl Monks concerning the following question:

I want to generate a chart using Chart::Graph::Gnuplot from a list of data files. This works: 
gnuplot({"title" => "foo"},
       [{"type" => "file"}, "cdb.7600.log"],
       [{"type" => "file"}, "cdb.8299.log"]);

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ie. I get a chart with two data sets on it. However, I want to pass the list of filenames on the command line. Here's the manpage: 
use Chart::Graph qw(gnuplot);

gnuplot(\%global_options, @data_sets);
gnuplot(\%global_options, [\%data_set_options, \@matrix], 
                          [\%data_set_options, \@x_column, \@y_column]
+,
                          [\%data_set_options, < filename >], ... );

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So, it looks to me like I can pass a reference to an array of data sets, where a data set is a hash, filename pair.. Here's my attempt: 
while($logfile = shift) {
    push @data_sets, ({"type" => "file"}, $logfile);
}

gnuplot({"title" => "foo"},
        \@data_sets);

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But, and here's the rub, the chart I get only ever has the first data set on it. Am I doing something stupid? (I hope so).

Any help would be appreciated, thanks.

Replies are listed 'Best First'.
Re: Stumped by Chart::Graph::Gnuplot parameters
by Masem (Monsignor) on Mar 05, 2001 at 19:07 UTC
    You're passing a reference to the data_sets array when the POD is saying that it needs an array. Try calling it with only "@data_sets" as opposed to "\@data_sets".
[reply]
      To be clear, the final solution is: 
      while($logfile = shift) {
    push @data_sets, [{"type" => "file"}, $logfile];
}

gnuplot({"title" => "foo"},
        @data_sets);

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[reply]
[d/l]

        the final solution is

        Heh! 

        gnuplot( {title=>"foo"}, map {[{type=>"file"},$_]} @ARGV );

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                - tye (but my friends call me "Tye")
[reply]
[d/l]
      Hmph, I remember trying that and it didn't work "Data set must be an array...", but, if I replace the round brackets with square brackets on the push line, it works!

      To be honest, I'm sure that's what I tried originally... well, it always ends up in tears when I randomly insert \s and [s until something works.

      Thanks a lot.

[reply]

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