Another way: 
my %where;
map {$where{$_} = 1} keys %firsthash;
map {$where{$_} += 10} keys %secondhash;

foreach (keys %where) {
  print "$_: first list only\n" if $where{$_} == 1;
  print "$_: second list only\n" if $where{$_} == 10;
}

[download]
Edited d/t typing too fast and not rereading. Thx injunjoel.

In reply to Re: Need advice on hashes and methods by BrianC
in thread Need advice on hashes and methods by tom2112

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