Kirk Strauser wrote:
At 2008-12-12T15:51:15Z, Marco Mariani <ma...@sferacarta.com> writes:
Filip Gruszczyński wrote:
I am not doing it, because I need it. I can as well use "if not elem
is None",
I suggest "if elem is not None", which is not quite the same.
So what's the difference exactly? "foo is not None" is actually surprising
to me, since "not None" is True. "0 is True" is False, but "0 is not None"
is True. Why is that?
>
I suppose that it should really be "not is" (cp "not in"), but Guido
chose to follow the English pattern "is not". "not" returns a Boolean
(or originally an int) and "is" checks for identity, but the result of
"is False" or "is True" is down to implementation details in the
interpreter, so you wouldn't write "is not ..." to mean "is (not ...)"
anyway, and in practice it's not a problem.
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