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

use Data::Dumper;

# Declare the hash reference with an empty hash
my $hash = {};

# assign the value "bar" to the key foo
$hash->{foo} = 'bar';

# This prints the values in the hash
# $VAR1 = {
#          'foo' => 'bar'
#         };
print Dumper $hash;

# you can retrieve the value by specifying the hash key directly also
# prints "bar"
print $hash->{foo} . "\n";

# we can use variables to assign key names:
foreach my $key (qw(abc def lmnop zaxy)) {
    my $value = reverse $key;
    $hash->{$key} = $value;
}

# since this is test data, I've just reversed the key names
# to show the differentiation between $KEY and $VALUE

# Now our hash looks something like this:
# $VAR1 = {
#          'zaxy' => 'yxaz',
#          'lmnop' => 'ponml',
#          'def' => 'fed',
#          'abc' => 'cba',
#          'foo' => 'bar'
#        };
print Dumper $hash;