Online PHP editor | refs for mqkLH

<?php $purchases = array( array('product_id' => 7, 'receipt' => "R13D13"), array('product_id' => 5, 'receipt' => "Y28Z14"), array('product_id' => 7, 'receipt' => "R02310"), array('product_id' => 5, 'receipt' => "E11403") ); $result = []; foreach($purchases as $key => $purchase) { if (!isset($result[$purchase["product_id"]])) { $result[$purchase["product_id"]] = $purchase; } } print_r($result);