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Thu Mar 8 17:22:41 CET 2012 · https://mail.python.org/pipermail/python-dev/2012-March/117442.html

Guido van Rossum wrote:
> On Wed, Mar 7, 2012 at 11:43 PM, Ethan Furman wrote:
>> Are you able to modify classes after class creation in Python 3? Without
>> using a metaclass?
> 
> Yes, by assignment to attributes. The __dict__ is a read-only proxy,
> but attribute assignment is allowed. (This is because the "new" type
> system introduced in Python 2.2 needs to *track* changes to the dict;
> it does this by tracking setattr/delattr calls, because dict doesn't
> have a way to trigger a hook on changes.)

Poorly phrased question -- I meant is it possible to add non-string-name 
attributes to classes after class creation.  During class creation we 
can do this:

--> class Test:
...   ns = vars()
...   ns[42] = 'green eggs'
...   del ns
...
--> Test
<class '__main__.Test'>
--> Test.__dict__
dict_proxy({
     '__module__': '__main__',
     42: 'green eggs',
     '__doc__': None,
     '__dict__': <attribute '__dict__' of 'Test' objects>,
     '__weakref__': <attribute '__weakref__' of 'Test' objects>,
     '__locals__': {
         42: 'green eggs',
        '__module__': '__main__',
        '__locals__': {...}}
     })
--> Test.__dict__[42]
'green eggs'

A little more experimentation shows that not all is well, however:

--> dir(Test)
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
TypeError: unorderable types: int() < str()

~Ethan~

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[Python-Dev] Non-string keys in type dict