PHP gets the month and week of the specified date

	//返回日期所在周是第几月第几周
	public function get_week_num(){
		// 当前日期
		$sdefaultDate = '2020-07-01';
		
		$first=1;
		
		$w = date('w', strtotime($sdefaultDate));
		//获取当前日期所在周的周一日期
		$week_start=date('Y-m-d', strtotime("$sdefaultDate -".($w ? $w - $first : 6).' days'));

		$m = date('Ym',strtotime($week_start));	//周一所属月份
		$start = date('Ym01',strtotime($week_start));	//当月一号
		$end = date('Ymd',strtotime($week_start));		//周一所在日期
		
		$n = 0;
		for($i = $start;$i <= $end;$i++){
			if(date('w',strtotime($i)) == 1){
				$n++;
			}
		}
		
		return $m.$n;
	}

Return format 2020065

Indicates that it is in the fifth week of June 2020