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| Date | Fri, 25 Nov 2011 19:46:17 +1100 |
| Subject | Re: Strange result ffor object to bool |
| From | Chris Angelico <rosuav@gmail.com> |
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On Fri, Nov 25, 2011 at 5:52 PM, ZhouPeng <zpengxen@gmail.com> wrote:
> I am sure listen is not None and can be accessed properly.
>
> But print bool(listen) is False
> if not listen is True
Casting something to boolean follows strict rules derived from the
notion that emptiness is false and nonemptiness is true. For instance:
>>> bool(""),bool([]),bool({}),bool(0)
(False, False, False, False)
Details here: http://docs.python.org/library/stdtypes.html
Chris Angelico
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Re: Strange result ffor object to bool Chris Angelico <rosuav@gmail.com> - 2011-11-25 19:46 +1100
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