3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $a = "ab"; echo preg_replace("/(a)|(b)/", "+$2+-$1-", $a);
based on dYqfv
Output for 5.6.0 - 5.6.30, hhvm-3.15.4, 7.0.0 - 7.2.6
++-a-+b+--