use strict; use warnings; use feature 'say';
use Data::Dumper;

my @arr = get_data();

say "Data:";
while ( my ($n, $aref) = each @arr ) {
    say "  Aref: " . ($n + 1);
    while ( my ( $n, $href ) = each @{ $aref } ) {
        say "    Href: " . ($n + 1);
        while ( my ( $key, $val ) = each %{ $href } ) {
            say "      $key: $val";
        }
    }
}

say '~~~~~~~~~~~~~~';

my @vals = map { $_->{'myKey'} } map { @{ $_ } } @arr;

say "Inner values:";
say Dumper \@vals;

sub get_data {
    my @arr;
    my @subArr1;
    my @subArr2;
    my %hash1 = ( myKey => 1 );
    my %hash2 = ( myKey => 2 );
    my %hash3 = ( myKey => 3 );
    my %hash4 = ( myKey => 4 );
    push(@subArr1, \%hash1, \%hash2);
    push(@subArr2, \%hash3, \%hash4);
    push(@arr, \@subArr1, \@subArr2);

    return @arr;
}

##</code><code>##

$ perl 1182753.pl
Data:
  Aref: 1
    Href: 1
      myKey: 1
    Href: 2
      myKey: 2
  Aref: 2
    Href: 1
      myKey: 3
    Href: 2
      myKey: 4
~~~~~~~~~~~~~~
Inner values:
$VAR1 = [
          1,
          2,
          3,
          4
        ];