$ cat test.pl use 5.18.0; use warnings; use Benchmark qw( cmpthese ); my $x = join " " => "", ("abc") x 5, ""; sub splt { join " " => split " " => $x; } sub rgx { $x =~ tr/ / /sr =~ s/^ //r =~ s/ $//r; } sub trx { my $y = $x =~ tr/ /x/cr; substr ($x, index ($y, "x"), rindex ($y, "x") - length ($x) + 1) =~ tr/ / /sr; } say "sourc: |$x|"; say "split: |", splt (), "|"; say "regex: |", rgx (), "|"; say "tr/x/: |", trx (), "|"; cmpthese (-2, { splt => \&splt, rgx => \&rgx, trx => \&trx });