3v4l.org

run code in 300+ PHP versions simultaneously
<?php $tree = array('id' => 1, 'children' => array(array('id' => 2, 'children' => array('id' => 4, 'children' => false)), array('id' => 3, 'children' => false))); print_r($tree); ?>
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Array ( [id] => 1 [children] => Array ( [0] => Array ( [id] => 2 [children] => Array ( [id] => 4 [children] => ) ) [1] => Array ( [id] => 3 [children] => ) ) )

preferences:
292.3 ms | 406 KiB | 460 Q