3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $x = 'someValue_subKey'; echo strtolower(preg_replace('/([a-z])([A-Z])/', '$1_$2', str_replace('_', '.', $x)));
Output for 4.3.0 - 5.6.28, hhvm-3.10.0 - 3.12.0, 7.0.0 - 7.1.0
some_value.sub_key