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

my %hash = map { chomp; split /,/ } <DATA>;
for (sort keys %hash) { print "$_ => $hash{$_}",$/; }

__DATA__
1001,choochoo
1002,candycane
1003,sockpuppet
1004,choochoo
1005,candycane
1006,sockpuppet6
1007,foo
1008,bar
0001,choochoo
0002,candycane
0003,sockpuppet
0109,choochoo