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Re: What is the semantics meaning of 'object'?

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From Ian Kelly <ian.g.kelly@gmail.com>
Date Sun, 23 Jun 2013 10:15:38 -0600
Subject Re: What is the semantics meaning of 'object'?
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On Sun, Jun 23, 2013 at 7:35 AM, Adam Jiang <jiang.adam@gmail.com> wrote:
> Another question raised here is that what is the proper way to refer
> to parent class? For example,
>
> class A(object):
>         def __init__(self, arg):
>                 print "A"
>
> class B(A):
>         def __init__(self, arg):
>                 super(B, self).__init__(arg)
>
> Is this correct? As the result, whenever you wanted to refer to a
> method in parent class, super() functions has to be called. This seems
> inefficient.

Generally, use super() any time you want to refer to a class attribute
(such as a method) in a parent class that is overridden in the child
class. Also note that in Python 3, the call "super(B, self)" can be
condensed to just "super()".

If you're worried about efficiency, you can also explicitly name the
superclass in order to call the method directly, like:

        A.__init__(self, arg)

However, super() is generally considered the right way to do this, in
order to avoid repeating the parent class name, for brevity in Python
3, and because it is needed to correctly handle some cases of multiple
inheritance.

> How to refer to a field defined in parent class?

For instance attributes or attributes that haven't been overridden,
just write "self.attribute_name".

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Thread

What is the semantics meaning of 'object'? Adam <jiang.adam@gmail.com> - 2013-06-22 19:58 -0700
  Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 03:20 +0000
    Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-22 22:27 -0600
      Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 05:23 +0000
        Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-22 23:40 -0600
          Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 17:29 +0000
            Re: What is the semantics meaning of 'object'? Rotwang <sg552@hotmail.co.uk> - 2013-06-24 02:53 +0100
              Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-24 06:31 +0000
                Re: What is the semantics meaning of 'object'? Rotwang <sg552@hotmail.co.uk> - 2013-06-24 16:00 +0100
                Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-24 11:23 -0600
    Re: What is the semantics meaning of 'object'? Adam Jiang <jiang.adam@gmail.com> - 2013-06-23 22:35 +0900
    Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-23 10:15 -0600
      Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 16:35 +0000
        Re: What is the semantics meaning of 'object'? Roy Smith <roy@panix.com> - 2013-06-23 12:49 -0400
          Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-23 11:08 -0600
            Re: What is the semantics meaning of 'object'? Roy Smith <roy@panix.com> - 2013-06-23 14:14 -0400
          Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-23 11:18 -0600
            Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 17:36 +0000
              Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-23 12:04 -0600
                Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 18:50 +0000
                Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-23 13:09 -0600
                Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-24 01:12 +0000
                Re: What is the semantics meaning of 'object'? Roy Smith <roy@panix.com> - 2013-06-23 15:24 -0400
                Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-24 01:27 +0000
                Re: What is the semantics meaning of 'object'? Roy Smith <roy@panix.com> - 2013-06-23 21:38 -0400
                Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-24 08:06 +0000
                Re: What is the semantics meaning of 'object'? Roy Smith <roy@panix.com> - 2013-06-24 08:41 -0400
                Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-24 08:58 -0700
                Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-24 23:51 +0000
                Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-24 11:26 -0600
                Re: What is the semantics meaning of 'object'? Ethan Furman <ethan@stoneleaf.us> - 2013-06-26 13:14 -0700
                Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-26 23:54 +0000
                Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-26 19:03 -0600
                Re: What is the semantics meaning of 'object'? Ethan Furman <ethan@stoneleaf.us> - 2013-06-26 17:38 -0700
          Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-23 18:46 +0000
            Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-23 13:05 -0600
            Re: What is the semantics meaning of 'object'? Ethan Furman <ethan@stoneleaf.us> - 2013-06-26 13:37 -0700
          Re: What is the semantics meaning of 'object'? Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-23 13:33 -0700
        Re: What is the semantics meaning of 'object'? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-23 21:33 +0200
        Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-25 11:44 -0600
        Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-25 14:58 -0700
        Re: What is the semantics meaning of 'object'? Chris Angelico <rosuav@gmail.com> - 2013-06-26 08:17 +1000
        Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-25 16:21 -0600
        Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-25 16:25 -0600
        Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-25 15:29 -0700
        Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-25 15:27 -0700
        Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-25 15:38 -0700
        Re: What is the semantics meaning of 'object'? Chris Angelico <rosuav@gmail.com> - 2013-06-26 08:39 +1000
        Re: What is the semantics meaning of 'object'? Chris Angelico <rosuav@gmail.com> - 2013-06-26 08:47 +1000
        Re: What is the semantics meaning of 'object'? Chris Angelico <rosuav@gmail.com> - 2013-06-26 08:57 +1000
          Re: What is the semantics meaning of 'object'? Rotwang <sg552@hotmail.co.uk> - 2013-06-26 16:16 +0100
            Re: What is the semantics meaning of 'object'? Chris Angelico <rosuav@gmail.com> - 2013-06-27 01:23 +1000
        Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-25 17:07 -0600
        Re: What is the semantics meaning of 'object'? Chris Angelico <rosuav@gmail.com> - 2013-06-26 09:08 +1000
        Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-25 17:10 -0600
        Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-25 16:19 -0700
          Re: What is the semantics meaning of 'object'? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-26 08:36 +0000
          Re: What is the semantics meaning of 'object'? alex23 <wuwei23@gmail.com> - 2013-06-28 10:19 +1000
            Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-28 11:55 -0700
        Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-25 16:00 -0700
        Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-25 18:19 -0600
        Re: What is the semantics meaning of 'object'? Mark Janssen <dreamingforward@gmail.com> - 2013-06-25 18:07 -0700
        Re: What is the semantics meaning of 'object'? Chris Angelico <rosuav@gmail.com> - 2013-06-26 17:25 +1000
        Re: What is the semantics meaning of 'object'? Ian Kelly <ian.g.kelly@gmail.com> - 2013-06-26 02:53 -0600
        Re: What is the semantics meaning of 'object'? Chris Angelico <rosuav@gmail.com> - 2013-06-26 09:54 +1000
        Re: What is the semantics meaning of 'object'? Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2013-06-26 12:56 +0200
      Re: What is the semantics meaning of 'object'? Rick Johnson <rantingrickjohnson@gmail.com> - 2013-06-23 13:12 -0700

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