in reply to Re: RFC: The Uniqueness of hashes.
in thread The Uniqueness of hashes.

And a variation on that, which handles duplicate values within the arrays as well:
$_{$_} .= 'a' for @foo; $_{$_} .= 'b' for @bar; # $_{$key} =~ /ab/ iff $key was in @foo and @bar # /a$/ iff $key was only in @foo # /^b/ iff $key was only in @bar # number of occurrences in # $foo_plus_bar = length($_{$key}); # $foo_only = ( $_{$key} =~ tr/a// ); # $bar_only = ( $_{$key} =~ tr/b// );
Adapting that to handle up to 26 arrays is trivial -- just set a scalar to 'a' for the first array, and increment it for each successive array; using a regex to determine the distribution for a given array value is left as an exercise...

(I updated the last three comment lines to be more consistent with the first three comment lines.)