Perl Data Types: hashes

my %roman = ('I' => 1, 'II' => 2, 'III' => 3, 'IV' => 4);

print $roman{'III'}, "\n";

print join(', ', keys(%roman)), "\n";

while(my($key, $value) = each(%roman)) {
  print "$key = $roman{$key}\n";
}

delete($roman{IV});

print join(', ', @roman{'I', 'II', 'III'}), "\n";