4.1

python datetime模块
#获取当前时间和日期
from datetime import datetime
now = datetime.now() # 获取当前datetime
print(now)
2021-12-01 16:28:07.198690
#获取指定时间和日期
dt = datetime(2021, 4, 19, 12, 20)
#2021-04-19 12:20:00

#str转为datatime

cday = datetime.strptime('2021-5-11 18:19:59', '%Y-%m-%d %H:%M:%S')
print(cday)
2021-05-11 18:19:59

#日期加减

>>> from datetime import datetime, timedelta
>>> now = datetime.now()
>>> now
datetime.datetime(2021, 5, 18, 16, 57, 3, 540997)
>>> now + timedelta(hours=10)
datetime.datetime(2021, 5, 19, 2, 57, 3, 540997)
>>> now - timedelta(days=1)
datetime.datetime(2021, 5, 17, 16, 57, 3, 540997)
>>> now + timedelta(days=2, hours=12)
datetime.datetime(2021, 5, 21, 4, 57, 3, 540997)