要获得与给定datetime对象对应的午夜，可以使用datetime.combine()方法:

>>> from datetime import datetime, time
>>> dt = datetime.utcnow()
>>> dt.date()
datetime.date(2015, 2, 3)
>>> datetime.combine(dt, time.min)
datetime.datetime(2015, 2, 3, 0, 0)

与.replace()方法相比，基于datetime.combine()的解决方案将继续工作，即使datetime模块引入了纳秒支持。

如果需要，tzinfo可以保留，但utc偏移量可能在午夜不同，例如，由于DST转换，因此一个简单的解决方案(设置tzinfo时间属性)可能会失败。参见如何获得给定时区的“午夜”UTC时间?

您可以使用熊猫(尽管它可能是该任务的开销)。你可以使用round, floor和celll来表示常用的数字，也可以使用任何熊猫频率的偏移别名:

import pandas as pd
import datetime as dt

now = dt.datetime.now()
pd_now = pd.Timestamp(now)

freq = '1d'
pd_round = pd_now.round(freq)
dt_round = pd_round.to_pydatetime()

print(now)
print(dt_round)

"""
2018-06-15 09:33:44.102292
2018-06-15 00:00:00
"""

我觉得这就是你要找的…

>>> import datetime
>>> dt = datetime.datetime.now()
>>> dt = dt.replace(hour=0, minute=0, second=0, microsecond=0) # Returns a copy
>>> dt
datetime.datetime(2011, 3, 29, 0, 0)

但如果你真的不关心时间方面的事情，那么你真的应该只传递日期对象……

>>> d_truncated = datetime.date(dt.year, dt.month, dt.day)
>>> d_truncated
datetime.date(2011, 3, 29)

有一个用来处理日期的很棒的库:Delorean

import datetime
from delorean import Delorean
now = datetime.datetime.now()
d = Delorean(now, timezone='US/Pacific')

>>> now    
datetime.datetime(2015, 3, 26, 19, 46, 40, 525703)

>>> d.truncate('second')
Delorean(datetime=2015-03-26 19:46:40-07:00, timezone='US/Pacific')

>>> d.truncate('minute')
Delorean(datetime=2015-03-26 19:46:00-07:00, timezone='US/Pacific')

>>> d.truncate('hour')
Delorean(datetime=2015-03-26 19:00:00-07:00, timezone='US/Pacific')

>>> d.truncate('day')
Delorean(datetime=2015-03-26 00:00:00-07:00, timezone='US/Pacific')

>>> d.truncate('month')
Delorean(datetime=2015-03-01 00:00:00-07:00, timezone='US/Pacific')

>>> d.truncate('year')
Delorean(datetime=2015-01-01 00:00:00-07:00, timezone='US/Pacific')

如果你想要返回datetime值:

>>> d.truncate('year').datetime
datetime.datetime(2015, 1, 1, 0, 0, tzinfo=<DstTzInfo 'US/Pacific' PDT-1 day, 17:00:00 DST>)

如果你想截断一个任意的timedelta:

from datetime import datetime, timedelta
truncate = lambda t, d: t + (datetime.min - t) % - d
# 2022-05-04 15:54:19.979349
now = datetime.now()

# truncates to the last 15 secondes
print(truncate(now, timedelta(seconds=15)))
# truncates to the last minute
print(truncate(now, timedelta(minutes=1)))
# truncates to the last 2 hours
print(truncate(now, timedelta(hours=2)))
# ...

"""
2022-05-04 15:54:15
2022-05-04 15:54:00
2022-05-04 14:00:00
"""

PS:这是针对python3的

你可以使用datetime。Strftime提取日，月，年…

例子:

from datetime import datetime
d = datetime.today()

# Retrieves the day and the year
print d.strftime("%d-%Y")

输出(今天):

29-2011

如果你只是想检索日期，你可以使用day属性:

from datetime import datetime
d = datetime.today()

# Retrieves the day
print d.day

输出(今天):

29