3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php $upgradeKeys = array( 'featured-listing', 'basic-pack', 'designer-blog', 'power-pack' ); $_upgradeKeys = array_diff( $upgradeKeys, array( 'featured-listing', 'basic-pack', 'designer-blog', 'power-pack' ) ); sort($_upgradeKeys); $upgradeKeys = $_upgradeKeys; $upgradeKeys[] = 'power-pack'; echo $a[0];
based on QFj6E
Output for 5.0.4 - 7.2.0
Notice: Undefined variable: a in /in/cYn41 on line 22
Output for 4.3.0 - 5.0.3
Notice: Undefined variable: a in /in/cYn41 on line 22