Online PHP editor | output for dST92

<?php $a = '{"id":41,"userId":9,"description":null,"updated_by":"Juan Dela Cruz","created_at":"2019-09-18 10:07:34","updated_at":"2019-09-18 10:07:34"}'; $b = '{"id":2,"userId":9,"description":null,"updated_by":null,"created_at":"2019-09-16 12:46:56","updated_at":"2019-09-16 12:46:56"}'; $arr1 = json_decode($a, true); $key1 = strtotime($arr1['created_at']); $arr[$key1] = $arr1; $arr2 = json_decode($b, true); $key2 = strtotime($arr2['created_at']); $arr[$key2] = $arr2; //print_r($arr); $key = max(array_keys($arr)); print_r($arr[$key]);