3v4l.org

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<?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);
Output for 8.1.32, 8.2.0 - 8.2.29, 8.3.0 - 8.3.26, 8.4.1 - 8.4.13
array ( '2011-11-18 00:00:00' => 3, '2011-11-22 00:00:00' => 2, )
preferences:
126.01 ms | 406 KiB | 5 Q