--TEST-- Moduloing strings --FILE-- <?php $s = "123"; $s1 = "test"; $s2 = "45345some"; $s %= 22; var_dump($s); $s1 %= 11; var_dump($s1); $s2 %= 33; var_dump($s2); echo "Done\n"; ?> --EXPECTF-- int(13) Warning: A non-numeric value encountered in %s on line %d int(0) Notice: A non well formed numeric value encountered in %s on line %d int(3) Done