How can I sort out an object is datetime or date in python?-CodePudding

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?

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

CodePudding user response：

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.

CodePudding user response：

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.