可以使用datetime库中的date类来判断一年中的第几天。下面是一个示例代码：
from datetime import datedef day_of_year(year, month, day):d = date(year, month, day)return d.timetuple().tm_ydayyear = 2022month = 3day = 15day_number = day_of_year(year, month, day)print("第{}天".format(day_number))这个代码会输出：第74天
