I updated my post Re: Help with function, count matches and store in hash & retrieve sorted, is that helpful to you?

Well, after looking yet again, I am still not sure. Can you give use the exact inputs that you are using so that we can run and exactly replicate your error with your data?

I am a bit puzzled about how you can get an undef value for $max_count? Which is assigned to the key "max". Of course:

my $element;
$element->{bar} = $key;
$element->{max} = $max_count;
$element->{max} //= 0; #### adding this prevents undef
push @match_count, $element;
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I guess I have the Sunday brain cramp.