php 獲取近1年的所有月份

源代碼

$z = date('Y-m');
            $a = date('Y-m', strtotime('-12 months'));
            $begin = new DateTime($a);
            $end = new DateTime($z);
            $end = $end->modify('+1 month');
            $interval = new DateInterval('P1M');
            $daterange = new DatePeriod($begin, $interval ,$end);

            foreach($daterange as $date){
                echo $date->format("Y-m") . "<br />";
            }