Online PHP editor | refs for 58v94

<?php $arr = array( array( 'imp' => 1000, 'clk' => 100, 'date' => 20150601 ), array( 'imp' => 1002, 'clk' => 102, 'date' => 20150602 ), array( 'imp' => 1003, 'clk' => 103, 'date' => 20150601 ) ); $result = array_reduce($arr, function($left, $right) { if(isset($right['imp'])) $left['imp'] += $right['imp']; if(isset($right['clk'])) $left['clk'] += $right['clk']; return $left; }, [ 'imp' => 0, 'clk' => 0 ]); print_r($result);