#!/usr/bin/env perl

use 5.010;
use strict;
use warnings;

my $animals = {
    gnu => {
        humps => 0,
    },
    dromedary => {
        humps => 1,
    },
    camel => {
        humps => 2,
    },
};

my @humps;
push @humps, $_->{humps} for map { $animals->{$_} } keys %$animals;
say "Unsorted humps: @humps";

my @sorted_animals = qw{gnu dromedary camel};
my @sorted_humps;
push @sorted_humps, $_->{humps} for map { $animals->{$_} } @sorted_animals;
say "Sorted humps: @sorted_humps";

##</code><code>##

$ pm_nested_hash_extract.pl
Unsorted humps: 2 0 1
Sorted humps: 0 1 2