Strange result ffor object to bool

Steven D'Aprano steve+comp.lang.python at pearwood.info
Fri Nov 25 03:59:41 EST 2011


On Fri, 25 Nov 2011 14:52:25 +0800, ZhouPeng wrote:

> Hi all,
> 
> In my program, I get a listen element by listen =
> graphics.find("listen")

What is a listen element? It is not a standard Python object. What 
library is it from?


> print listen is <Element listen at 6afc20> print type listen is <type
> 'instance'> I am sure listen is not None and can be accessed properly.
> 
> But print bool(listen) is False

What makes you think this is a strange result? Many things are false:

py> for obj in (None, [], {}, 0, 0.0, "", 42):
...     print bool(obj),
... 
False False False False False False True


-- 
Steven



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