Online PHP editor | refs for ROTMP

<?php $arrRes = array( array("2018-08-01"=>"X" , "2018-08-02"=>"O" , "2018-08-03"=>"O" , "2018-08-04"=>"O"), array("2018-08-01"=>"X" , "2018-08-02"=>"X" , "2018-08-03"=>"O" , "2018-08-04"=>"O"), array("2018-08-01"=>"X" , "2018-08-02"=>"X" , "2018-08-03"=>"O" , "2018-08-04"=>"X"), array("2018-08-01"=>"X" , "2018-08-02"=>"O" , "2018-08-03"=>"O" , "2018-08-04"=>"O"), ); $arraySum = ['rows' => ['X'=>[0,0,0,0],'O'=>[0,0,0,0]],'cols' => ['X'=>[0,0,0,0],'O'=>[0,0,0,0]]]; foreach($arrRes as $keyRow => $row){ foreach($row as $keyCol => $col){ $arraySum['rows'][$col][$keyRow]++; $arraySum['cols'][$col][array_search($keyCol,array_keys($row))]++; } } echo "<pre>".print_r($arraySum,1)."</pre>";