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

Groups > comp.lang.python > #83767

Re: Calling a derived class's constructor from a parent method

Show key headers only | View raw

On 14/01/2015 16:45, jason wrote:
> If I have a class hierarchy like so:
>
>
> class A(object):
>        def __init__(self, s):
>              self.s = s
>        def foo(self, s):
>              return A(s)
>
> class B(A):
>        def __init__(self, s):
>              A.__init__(self, s)
>
> If I make a B:
>
> b = B(0)
>
> I'd like b.foo(1) to return an instance of B. Is there a way to do that besides implementing a construct(self, s) for each part of the hierarchy? I.e. is there a way for the base class to look at self and find out what type to create?
>
> I'm using Python 2.7.5, but I'm curious what the 3.x answer is too.
>

I'm confused, can you please explain what you're trying to achieve 
rather than how you're trying to achieve it and I'm sure that others 
will give better answers than I can :)

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence

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

Thread

Calling a derived class's constructor from a parent method jason <jasonsewall@gmail.com> - 2015-01-14 08:45 -0800
  Re: Calling a derived class's constructor from a parent method Ian Kelly <ian.g.kelly@gmail.com> - 2015-01-14 10:00 -0700
  Re: Calling a derived class's constructor from a parent method Chris Angelico <rosuav@gmail.com> - 2015-01-15 03:56 +1100
  Re: Calling a derived class's constructor from a parent method Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-01-14 17:05 +0000
    Re: Calling a derived class's constructor from a parent method jason <jasonsewall@gmail.com> - 2015-01-14 10:10 -0800
      Re: Calling a derived class's constructor from a parent method Dave Angel <davea@davea.name> - 2015-01-14 13:41 -0500
    Re: Calling a derived class's constructor from a parent method alister <alister.nospam.ware@ntlworld.com> - 2015-01-14 18:18 +0000
  Re: Calling a derived class's constructor from a parent method Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-01-15 11:40 +1100
    Re: Calling a derived class's constructor from a parent method Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-01-15 04:44 +0000

csiph-web