Programming Perl, 4th Edition

Composition of a Hash of Hashes

You can create a hash of anonymous hashes as follows:

%HoH = (
    flintstones => {
        husband   => "fred",
        pal       => "barney",
    },
    jetsons => {
        husband   => "george",
        wife      => "jane",
        "his boy" => "elroy",  # Key quotes needed.
    },
    simpsons => {
        husband   => "homer",
        wife      => "marge",
        kid       => "bart",
    },
);

To add another anonymous hash to %HoH, you can simply say:

$HoH{ mash } = {
     captain  => "pierce",
     major    => "burns",
     corporal => "radar",
 };