python的datetime模块的实用功能

import datetime

date = datetime.date(2018, 7, 17)
time = datetime.time(8, 15, 10)
dt = datetime.datetime.combine(date, time)
print(dt)

import datetime

dt1 = datetime.datetime(2018, 7, 1, 16, 15, 10)
dt2 = dt1 + datetime.timedelta(weeks=-2)
print(dt1)
print(dt2)
print(dt1 - dt2)
print(dt2 - dt1)

2018-07-01 16:15:10
2018-06-17 16:15:10
14 days, 0:00:00
-14 days, 0:00:00