3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $pattern = '#\d+#'; $haystack = '0123 456 789'; echo preg_replace_callback($pattern, 'add_three', $haystack); function add_three($matches){ return '-'.$matches[0].'-'; }
based on IPGuP
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
-0123- -456- -789-