Actually, I get the exact same output from both solutions, which works just great for me :) So thank you both.

I end up with: 

$VAR1 = {
          'R1' => {
                  },
          'R2' => {
                  }
             ...
        };
$VAR1 = {
          'R1' => {
                  },
          'R2' => {
                  }
             ...
        };
         ...

[download]
However, I will be using: 
foreach my $lig (keys %{$ligHash})
{
    findIntersection($ligHash->{$lig}, $lig);
}

[download]
Because it gives me the option to easily pass the hash name (i.e. '34k') as a string.

Did either of you intend on a different output? If so I would be interested in that as well.

In reply to Re^2: Problem cycling through top level of nested hashes by tomdbs98
in thread Problem cycling through top level of nested hashes by tomdbs98

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