Anonymonk:

I know you've specified a 2D matrix, but in this case, I think a hash would be simpler. Think of the hash as a sparse array. Something like this:

#!/usr/bin/perl -w
use warnings;
use strict;

my @animals = ("cat", "dog", "fish", "horse", "pig");

my %count;

while (<DATA>) {
        my ($x,$y) = split /\s/;
        ($x,$y) = ($y,$x) if ($x gt $y);
        $count{$x}{$y}++;
}

for my $x (sort keys %count) {
        for my $y (sort keys %{$count{$x}}) {
                print $count{$x}{$y}," people have both a ",
                        $x, " and a ", $y, "\n";
        }
}

__DATA__
cat dog
cat fish
pig dog
horse fish
pig fish
dog fish
fish cat

[download]
--roboticus

In reply to Re: help with 2D arrays with perl requested by roboticus
in thread help with 2D arrays with perl requested by Anonymous Monk

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