【Python实例】获取今日零点的datetime

datetime 的 Python 官方文档地址：​​https://docs.python.org/zh-cn/3/library/datetime.html​​

实现今日零点的实例（其中 t4 和 t5 均为当日零点，其中 t4 为更推荐的方法）：

from datetime import date, datetime, time, timedelta
from timeit import timeit

if __name__ == "__main__":
    t1 = datetime.now()
    t2 = datetime.today()
    t3 = date.today()
    t4 = datetime.combine(date.today(), time.min)
    now = datetime.now()
    t5 = now - timedelta(hours=now.hour, minutes=now.minute, seconds=now.second,
                         microseconds=now.microsecond)
    print(type(t1), t1)  # <class 'datetime.datetime'> 2022-09-15 14:17:53.419055
    print(type(t2), t2)  # <class 'datetime.datetime'> 2022-09-15 14:17:53.419056
    print(type(t3), t3)  # <class 'datetime.date'> 2022-09-15
    print(type(t4), t4)  # <class 'datetime.datetime'> 2022-09-15 00:00:00
    print(type(t5), t5)  # <class 'datetime.datetime'> 2022-09-15 00:00:00
    print(t4 == t5)  # True

    tt1 = timeit("datetime.combine(date.today(), time.min)",
                 setup="from datetime import datetime, date, time")
    tt2 = timeit("now = datetime.now()\n"
                 "now - timedelta(hours=now.hour, minutes=now.minute, seconds=now.second, "
                 "microseconds=now.microsecond)",
                 setup="from datetime import datetime, timedelta")
    print(tt1, tt2)  # 2.26664 3.4059334