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Subject: datetime as subclass of date
From: Skip Montanaro <skip@pobox.com>
To: Python <python-list@python.org>
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Xref: csiph.com comp.lang.python:64610

This took my by surprise just now:

>>> import datetime
>>> now = datetime.datetime.now()
>>> isinstance(now, datetime.datetime)
True
>>> isinstance(now, datetime.time)
False
>>> isinstance(now, datetime.date)
True
>>> issubclass(datetime.datetime, datetime.date)
True

I'd never paid any attention to the relationship between the datetime,
time, and date classes of the datetime module before now, but have an
application where, for backwards compatibility, date objects must be
mapped to datetime objects with a time of midnight. That wasn't
working, because I was asking if a datetime instance was an instance
of a date. Which, it turns out, it is.

Skip