Online PHP editor | refs for TLYSI

<?php $orders = [ ['order_id' => 44925, 'carrier_tracking_code' => 'LB399189926US'], ['order_id' => 44923, 'carrier_tracking_code' => '9205590221582717353066'], ['order_id' => 44490, 'carrier_tracking_code' => '9205590221582717353080'], ]; $customers = [ 79 => ['order_id' => 44490, 'customers_email_address' => 'test@test.com', 'customers_name' => 'JTest name'], 80 => ['order_id' => 44923, 'customers_email_address' => ' test@test.com', 'customers_name' => 'Test name'], 81 => ['order_id' => 44925, 'customers_email_address' => ' test@test.com', 'customers_name' => 'Test name'] ]; $customer_index = array_combine(array_keys($customers), array_column($customers, 'order_id')); $result = []; foreach ($orders as $key => $order) { $result[$key] = $order; $customer = array_search($order['order_id'], $customer_index); $result[$key]['customer'] = $customer ? $customers[$customer] : []; } print_r($result);