Question

Assuming I have a hash like this:

$hash_ref = {

  'hashes' => {
    'h1' => { 'klf' => '1', 'moomooland' => '1' },
    'h2' => { 'klf' => '2', 'moomooland' => '2' },
    'h3' => { 'klf' => '3', 'moomooland' => '3' }
  },

  'keys' => {
    'k1' => 'key1',
    'k2' => 'key2',
    'k3' => 'key3'
  }

}

How could I find out, as easy as possible, that hashes contains 3 more hashes, while keys contains 3 key/value pairs?

ref will return HASH for both of them, and I am not sure if it is possible to maybe find out the depth of these hashes.

Thanks 🙂

Answer 1

If you just need to know if a hash is multi-dimensional, you can iterate over its values and stop if a reference is found:

my $is_multi_dimensional = 0;

for my $value (values %$hash_ref) {
    if ('HASH' eq ref $value) {
        $is_multi_dimensional = 1;
        last;
    }
}

or you can use the each() function:

while (my (undef, $value) = each %$hash_ref) {
    if ('HASH' eq ref $value) {
        $is_multi_dimensional = 1;
        last;
    }
}