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<?php $myArray = array( '2019-09-28' => array ( 'A' =>4, 'B' => 85, 'C' =>200 ), '2019-09-29' => array ( 'A' =>5, 'B' => 83, 'C' =>202 ) ); $result_arr = []; array_walk($myArray,function($value,$key) use (&$result_arr){ foreach($value as $k=> $val){ $result_arr[$k][$key] = $val; } }); print_r($result_arr);
Output for 7.1.25 - 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 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.25, 8.4.1 - 8.4.12
Array ( [A] => Array ( [2019-09-28] => 4 [2019-09-29] => 5 ) [B] => Array ( [2019-09-28] => 85 [2019-09-29] => 83 ) [C] => Array ( [2019-09-28] => 200 [2019-09-29] => 202 ) )

preferences:
96.18 ms | 408 KiB | 5 Q