$test) { list($string, $codes) = $test; $words = explode(" ", $string); foreach($words as $a => $word) { if (strlen($word) == 4) { $words[$a] = $word[2].$word[3].$word[0].$word[1]; } } $string = implode(" ",$words); yield $name => [$string, $codes]; } } }