3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $card_no = "12345678901"; $no = str_pad(substr($card_no, -4), strlen($card_no), 'X', STR_PAD_LEFT); echo $no; ?>
Output for 4.3.0 - 7.2.0
XXXXXXX8901