Unclear datetime.date type when using isinstance

[Mailing List]

Was including a input check on a function argument which is expecting a
datetime.date. When running unittest no exception was raised when a
datetime.datetime instance was used as argument. Some playing with the
console lead to this:

True

True

My issue (or misunderstanding) is in the first part, while dt1 is a
datetime.date object (confirmed by type), the isinstance(dt1,
datetime.datetime) returns True. Is this correct? If so, is it possible
to verify whether an object is indeed a datetime.date and not a
datetime.datetime object?

For background information; reason my choice was to use the
datetime.date object is that there should not be ay time information in
the object. Of course this can easily be stripped off in the function,
but thought the use of a datetime.date would be a nice shortcut...

 

[Diez B. Roggisch]

Was including a input check on a function argument which is expecting a
datetime.date. When running unittest no exception was raised when a
datetime.datetime instance was used as argument. Some playing with the
console lead to this:

True

My issue (or misunderstanding) is in the first part, while dt1 is a
datetime.date object (confirmed by type), the isinstance(dt1,
datetime.datetime) returns True. Is this correct? If so, is it possible
to verify whether an object is indeed a datetime.date and not a
datetime.datetime object?

I think you got it wrong here: dt1 is a *datetime* object, and also a
date-object. I guess that's because it conforms to the same protocol -
it has year, month and day and so forth.

For background information; reason my choice was to use the
datetime.date object is that there should not be ay time information in
the object. Of course this can easily be stripped off in the function,
but thought the use of a datetime.date would be a nice shortcut...

Obviously not You can of course test not on inheritance (which
isinstance does), but actual type equality:
False


Diez