Do not use map in void context. Although it probably doesn't generate the output list in current versions of Perl, it does send wrong signals about the intent of the code. Use for as a statement modifier instead:

    $result->{$_}{$array_name} = 1 for @{$arrays->{$array_name}}

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True laziness is hard work

In reply to Re^2: Array comparison for 3 arrays by GrandFather
in thread Array comparison for 3 arrays by terrylau

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