2011/10/27 candide <candide@free.invalid> > I realize that built-in types objects don't provide a __dict__ attribute > and thereby i can't set an attribute to a such object, for instance > > > >>> a=[42,421] > >>> a.foo="bar" > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > AttributeError: 'list' object has no attribute 'foo' > >>> a.__dict__ > Traceback (most recent call last): > File "<stdin>", line 1, in <module> > AttributeError: 'list' object has no attribute '__dict__' > >>> > > > So, i was wondering : > > -- why this behaviour ? >
performance > -- where the official documentation refers to this point ? > it's here and there in python documentation. I did not find specific documentation about the __dict__ property. Have a look at : - naming conventions in http://www.python.org/dev/peps/pep-0008/ - http://docs.python.org/library/stdtypes.html#modules __dict__ is similar to other __*__ properties and has a function that actually use it to do something usefull aka. dir http://docs.python.org/library/functions.html#dir The way I understand it is that it's for internal use but it's exposed for debugging (and learning ?) purpose.
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