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

# initialize a hash with a list of key value pairs
my %domains1 = ( 'com', 'commercial', 'edu', 'educational', 'org', 'non-profit' );

# same as above but using => in place of comma
my %domains2 = ( 'com' => 'commercial', 'edu' => 'educational', 'org' => 'non-profit' );

# same as above but when using => keys do not have to be quoted
my %domains3 = ( com => 'commercial', edu => 'educational', org => 'non-profit' );

# same as above but without extra spaces
my %domains4 = ( com=>'commercial', edu=>'educational', org=>'non-profit' );

print "domains1:\n";
for my $key ( keys %domains1 )
{
  print "\t$key $domains1{$key}\n";
}

print "domains2:\n";
for my $key ( keys %domains2 )
{
  print "\t$key $domains2{$key}\n";
}

print "domains3:\n";
for my $key ( keys %domains3 )
{
  print "\t$key $domains3{$key}\n";
}

print "domains4:\n";
for my $key ( keys %domains4 )
{
  print "\t$key $domains4{$key}\n";
}