I assume that by "replace" you mean to use data loaded dynamically, rather than statically.

Something along the lines of the following fragment should do. It assumes three comma-delimited numbers per row of data.

while ( <DATA> ) {
    chomp;
    my($a,$b,$c) = split;
    push @{$data[0]}, $a;
    push @{$data[1]}, $b;
    push @{$data[2]}, $c;
}
open(IMG, ">chart.png") or die("chart.png: $!");
binmode(IMG);
print IMG $graph->plot(\@data);
close(IMG);
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