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

my %hoa = (
    'foo' => [ 1, 3, 5 ],
    'bar' => [ 4, 5, 6 ],
    'rat' => [ 8, 4, 2 ],
);

print( "$_ ", join( ', ' => @{$hoa{$_}} ), "\n" )
    for sort keys %hoa;
print "\n";

=over
bar 4, 5, 6
foo 1, 3, 5
rat 8, 4, 2
=cut

my %hoaoa = (
    'Foo' => [ [1,2], [3,4], [5,6] ],
    'Bar' => [ [3,5], [5,7], [7,9] ],
    'Rat' => [ [0,1], [2,1], [4,1] ],
);

print( "$_ ", join( ', ' => map { $_->[0] } @{$hoaoa{$_}} ), "\n" )
    for sort keys %hoaoa;
print "\n";

=over
Bar 3 5 7
Foo 1 3 5
Rat 0 2 4
=cut
__END__