Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.python > #42562

Re: extending class static members and inheritance

Date 2013-04-02 09:42 -0400
From Dave Angel <davea@davea.name>
Subject Re: extending class static members and inheritance
References <kjembp$ok3$1@ger.gmane.org>
Newsgroups comp.lang.python
Message-ID <mailman.39.1364910192.17481.python-list@python.org> (permalink)

Show all headers | View raw


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

Back to comp.lang.python | Previous | Next | Find similar | Unroll thread


Thread

Re: extending class static members and inheritance Dave Angel <davea@davea.name> - 2013-04-02 09:42 -0400

csiph-web