Thanks for all your help. Lots of good stuff here. At the risk of appearing useless I may need some help with code provided by TedPride ( very cool BTW ). 
sub remove {
    my ($p, $d) = @_;
    if ($d-- > 1) {
        remove($_, ($d)) for values %$p; # Had second decrement here
    }
    else {
        my %newhash;
        for (values %$p) {
            @newhash{keys %$_} = values %$_;
        }
        $_[0] = \%newhash;
    } 
}

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I've not seen one of these before. It's an hash but it looks like an array ie '@' 
for (values %$p) {
            @newhash{keys %$_} = values %$_;
        }
        $_[0] = \%newhash;

[download]
What is going on here then ? Checked out my cookbook etc but can't find a reference to this syntax. One other slight complication is the data can actually look like this; 
$W={
    'A' => {
        'L' => {
            'D'=>99,
            'X'=>99,
              },
        'C' =>{
            'E'=>99
             },
          }, 
    'X' => {
        'Q'=>{
            'O'=>99,
            },
        'T'=>{
            'U'=>99,
            },
          }, 
        'W' => 99,
    };

[download]
Now when we collapse level 2 ie LCQT I don't want to change the value for 'W'. So only drop values on the target level if they are HASH. So really it's a mix of H,HOH and HOHOH etc. Thanks again for your help. Jeff

In reply to recursive hash layer removal question by wertert
in thread recursive hash layer removal question by wertert

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