在coding的过程中有时候会需要用到一些特殊日期，比如说是一个月的最后一天的日期，昨天的日期等等。
1 def first_day_of_next_month(self, old_date): 2 old_date = datetime.datetime.strptime(old_date, "%Y-%m-%d") 3 next_month = old_date.replace(day=28) + datetime.timedelta(days=4) 4 next_month = next_month.replace(day=1) 5 return next_month.strftime("%Y-%m-%d") 6 7 def last_day_of_month(self, any_day): 8 any_day = datetime.datetime.strptime(any_day, "%Y-%m-%d") 9 next_month = any_day.replace(day=28) + datetime.timedelta(days=4) # this will never fail 10 return (next_month - datetime.timedelta(days=next_month.day)).strftime("%Y-%m-%d") 11 12 def get_last_day(self, current_date): 13 current_date = datetime.datetime.strptime(current_date, "%Y-%m-%d") 14 last_date = current_date + datetime.timedelta(days=1) 15 return last_date.strftime("%Y-%m-%d")