3v4l.org

run code in 300+ PHP versions simultaneously
<?php $array = [ ['toxic', 'irritant', 'flammable'], ['toxic', 'irritant'], ['toxic'], ]; $result = []; array_walk_recursive( $array, function ($leafNode) use (&$result) { $result[$leafNode] = ($result[$leafNode] ?? 0) + 1; } ); var_export($result);
Output for 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
array ( 'toxic' => 3, 'irritant' => 2, 'flammable' => 1, )
preferences:
46.27 ms | 402 KiB | 62 Q