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Date: Tue, 02 Apr 2013 09:42:44 -0400
From: Dave Angel <davea@davea.name>
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To: python-list@python.org
Subject: Re: extending class static members and inheritance
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On 04/02/2013 09:27 AM, Fabian PyDEV wrote:
> Hi All,
>
> I have a question.
>
> Let says I have the following two classes:
>
> class Base(object):
> 	__mylist__ = ["value1", "value2"]
>
> 	def somemethod(self):
> 		pass
>
>
> class Derived(Base):
> 	__mylist__ = ["value3", "value4"]
>
> 	def anothermethod(self):
> 		pass
> 	
> 	
>
>
> what I would like to accomplish is that the class Derived has the member __mylist__ extended or merged as ["value1", "value2", "value3", "value4"].
>
> Is there anyway I could accomplish this?
>
> I was thinking on accomplishing this as follows:
>
>
> class Derived(Base):
> 	__mylist__ = Base.__mylist__ + ["value3", "value4"]
>
> 	def anothermethod(self):
> 		pass
>
>
> Is there a better way? Perhaps a decorator?
>

This is already done the best (clearest) way I know of.

However, I'd like to point out two things:
1) they're not called class members, but class attributes.  You have 
class attributes and instance attributes.

2) dunder methods should only be used to fulfill special methods defined 
by the language.  If it's a public attribute, just leave off the 
underscores entirely. And if it's private, put just one leading underscore.



-- 
DaveA