- var_export: documentation ( source)
<?php
$array = [
['_id' => '5f76b1788ee23077dccd1a2c', 'product' => ['_id'=>'5d0391a4a72ffe76b8fcc610'], 'count'=> 1],
['_id' => '5f76b6288ee2300700cd1a3a', 'product' => ['_id'=>'5d0391b6a72ffe76b8fcc611'], 'count'=> 1],
['_id' => '5f76d2488ee23083d3cd1a4a', 'product' => ['_id'=>'5d0391b6a72ffe76b8fcc611'], 'count'=> 1]
];
$productCounts = [];
foreach ($array as $item) {
$productId = $item['product']['_id'];
$productCounts[$productId] = ($productCounts[$productId] ?? 0) + $item['count'];
}
var_export($productCounts);