Online PHP editor | refs for tRonD

<?php $array = [ [ ["2011-11-18 00:00:00" => 'C'], ["2011-11-18 00:00:00" => 'I'], ["2011-11-18 00:00:00" => 'S'], ], [ ["2011-11-22 00:00:00" => 'C'], ["2011-11-22 00:00:00" => 'S'] ] ]; $result = []; array_walk_recursive($array, function ($_, $k) use (&$result) { $result[$k] = ($result[$k] ?? 0) + 1; }); var_export($result);