3v4l.org

run code in 300+ PHP versions simultaneously
<?php for($i=0;$i<256;$i++){ $data = "a".chr($i)."b"; $a=preg_replace("/[^-_a-z]/", "", $data); if($a!="ab") echo chr($i)."\n"; } ?>
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.36, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
- _ a b c d e f g h i j k l m n o p q r s t u v w x y z
preferences:
224.8 ms | 406 KiB | 363 Q