php 获取近一周的日期

 public function get_weeks($time = '', $format='Y-m-d'){
        $time = $time != '' ? $time : time();
        //组合数据
        $date = [];
        $a= 0;
        for ($i=1; $i<=7; $i++){
            $date[$a] = date($format ,strtotime( '+' . $i-7 .' days', $time));
            $a++;
        }
        return $date;
    }