Function __defaults__

Terry Reedy tjreedy at udel.edu
Sun Apr 24 18:48:49 CEST 2011


On 4/24/2011 5:58 AM, Steven D'Aprano wrote:
> Consider this in Python 3.1:
>
>
>>>> def f(a=42):
> ...     return a
> ...
>>>> f()
> 42
>>>> f.__defaults__ = (23,)
>>>> f()
> 23
>
>
> Is this an accident of implementation, or can I trust that changing
> function defaults in this fashion is guaranteed to work?

Interesting question. It seems not to be documented, so I would not 
count on anything. This is a bit of a gray area, and if you get no 
answer here, try pydev list, perhaps as a request that special names be 
more completely documented, even is just as implementation details 
subject to change.


-- 
Terry Jan Reedy




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