3v4l.org

run code in 300+ PHP versions simultaneously
<?php $testArray = array(1, 'test' => array('a' => array('percy', 'mitch'),'b','c')); $helper = array(); array_walk_recursive( $testArray, function ($item, $key) use (&$helper) { if ($key === 'a') { $helper[] = $item; } } ); var_dump($helper);

preferences:
44.29 ms | 402 KiB | 5 Q