Online PHP editor | refs for E3q4H

<?php $array = [ ['_id' => '5f76b1788ee23077dccd1a2c', 'product' => ['_id'=>'5d0391a4a72ffe76b8fcc610'], 'count'=> 1], ['_id' => '5f76b6288ee2300700cd1a3a', 'product' => ['_id'=>'5d0391b6a72ffe76b8fcc611'], 'count'=> 1], ['_id' => '5f76d2488ee23083d3cd1a4a', 'product' => ['_id'=>'5d0391b6a72ffe76b8fcc611'], 'count'=> 1] ]; $result = []; foreach ($array as $item) { $productId = $item['product']['_id']; if (!isset($result[$productId])) { $result[$productId] = $item; } else { $result[$productId]['count'] += $item['count']; } } var_export(array_values($result));