my @a = qw(1 11);
my @b = qw(1a 2b);

($a,$b) = qw(11 a);
print "Why am I printing?$/" unless (exists { map { $a[$_].$b[$_] => $
+_ } 0..$#a }->{$a.$b});
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Of course, if you can guarantee @a contains only numerals and @b contains no numerals, then your solution works as advertised. However, this solution does break down when either array can contain any character.