$ perl -e' my @input = ( -222, -221, -21, 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144 ); sub oddDigitSum { my @ans; for ( @_ ) { my $sum; $sum += $_ for /\d/g; $sum % 2 && push @ans, $_; } return @ans; } print "@{[ oddDigitSum @input ]}\n"; '