note ikegami <p>A problem with your question, not an answer to your question: <br><c>@data = map { s/./X/; $_} @data;</c> <br>is incorrect too. Redundant, at least. It does the same as <br><c>map { s/./X/ } @data;</c> <br>which is a poor way (in my opinion) to write <br><c>s/./X/ for @data;</c> <p>If you're setting up a chain, you'd want one of <br><c>map { my $s = $_; $s =~ s/./X/; $s }</c> <br><c>apply { s/./X/ } # From List::MoreUtils</c> <br><c>Filter { s/./X/ } # From Algorithm::Loops</c> 728569 728569