获从2017-2 到现在所有月份;

public function get_mouthlist($start_time){
    //$start_time = '2018-02';                //线上起始位置为2018-03
    $end_time = date('Y-m',time());

    //所有可选的日期月份列表(从2018-03开始到当前月份)
    $end_year = date('Y');
    $end_mouth = (int)array_pop(explode('-',$end_time));


    $start_year = array_shift(explode('-',$start_time));
    $start_mouth = array_pop(explode('-',$start_time));

    for ($k=$end_year;$k>=$start_year;$k--){
        if ($k == $end_year){
            if ($k == $start_year){
                for ($i=$end_mouth;$start_mouth<=$i;$i--){
                    $date_array[] = $k.'-'.$i;
                }
            }else{
                for ($i=$end_mouth;1<=$i;$i--){
                    $date_array[] = $k.'-'.$i;
                }
            }
        }else{
            if ($k == $start_year){
                for ($i=12;$start_mouth<=$i;$i--){
                    $date_array[] = $k.'-'.$i;
                }
            }else{
                for ($i=12;1<=$i;$i--){
                    $date_array[] = $k.'-'.$i;
                }
            }
        }
    }
　　return $data_array;
}