如何整理出一个object是datetime还是python中的date？

Question

I am trying to develop a logic that depends on the type of the input being date or datetime. To achieve this goal, I used isinstance with datetime.date and datetime.datetime . Unfortunately, it seems like that a datetime.datetime object is considered an instance of datetime.date .

import datetime

date_obj = datetime.date.today()
datetime_obj = datetime.datetime.now()


type(date_obj)
# <class 'datetime.date'>

type(datetime_obj)
# <class 'datetime.datetime'>


isinstance(date_obj, datetime.date)
# True
isinstance(datetime_obj, datetime.date)
# True


isinstance(date_obj, datetime.datetime)
# False
isinstance(datetime_obj, datetime.date)
# True

I suspected that datetime.date might be considered a subclass of datetime.datetime but that's not the case:

issubclass(datetime.date, datetime.datetime)
# False
issubclass(datetime.datetime, datetime.date)
# True

What's the pythonic way of figureing out whether an object is a date or a datetime?

PS I checked this related question , but that doesn't resolve my issue.

Answer 1

You can retrieve the exact type of the objects with type , and check whether it's date or datetime using is :

>>> type(date_obj) is datetime.date
True
>>> type(date_obj) is datetime.datetime
False

>>> type(datetime_obj) is datetime.date
False
>>> type(datetime_obj) is datetime.datetime
True

Note that type objects are unique , so comparing them using is is well defined.

Answer 2

You can check first for the wider type, then the other:

if isinstance(obj, datetime.date):
    # it's a date, not a datetime
    ...
elif isinstance(obj, datetime.datetime):
    # it's a datetime, not a date
    ...

Because every datetime.datetime object is also a datetime.date object, but the reverse is not generally true.