If you need to use a test like that, you've already gone too far down the road o...

pyre · on March 6, 2014

It's functionality that someone went out of their way to create:

    def __bool__(self):
        if self.second or self.microsecond:
            return True
        offset = self.utcoffset() or timedelta(0)
        return timedelta(hours=self.hour, minutes=self.minute) != offset

http://hg.python.org/cpython/file/302c8fdb17e3/Lib/datetime....

Now that I look at the actual code, it makes less sense. It's not just midnight that evaluates to False. It's midnight UTC that evals to False. So if your timezone is PST, then 8AM evals to False. Since most datetime.time() objects are timezone 'dumb' by default, this distinction doesn't matter so much, but I can see this still biting some people hard, even if "Midnight is false-y" made sense.

Edit: Also, to the "explicit is better than implicit" crowd, notice this line (in core libs):

  if self.second or self.microsecond:
      return True

It's not:

  if self.second != 0 or self.microsecond != 0:
      return True

What could be more 'Pythonic' than the Python core libraries?

Edit: s/EST/PST/ ^^;;

lstamour · on March 6, 2014

Perhaps it started because as time zones were added, they wanted to reflect that 8am_pacific == midnight_utc, assuming there aren't any offsets for daylight savings in effect...