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Re: newb __init__ inheritance

References (1 earlier) <jjg4p3$lst$1@theodyn.ncf.ca> <jjglmi$dao$1@theodyn.ncf.ca> <2feb13ca-f83b-4843-995f-ee77e7505ecd@db5g2000vbb.googlegroups.com> <mailman.560.1331462311.3037.python-list@python.org> <18769501.3541.1331463388634.JavaMail.geo-discussion-forums@ynkz21>
From Ian Kelly <ian.g.kelly@gmail.com>
Date 2012-03-11 05:40 -0600
Subject Re: newb __init__ inheritance
Newsgroups comp.lang.python
Message-ID <mailman.563.1331466085.3037.python-list@python.org> (permalink)

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On Sun, Mar 11, 2012 at 4:56 AM, hyperboogie <hyperboogie@gmail.com> wrote:
> 1. What do you mean by "subclassing `object`"?

In Python 2 there are two different types of classes: classic classes,
which are retained for backward compatibility, and new-style classes,
which were introduced in Python 2.2.  Classic classes are the default.
 In order to get a new-style class (strongly recommended), your class
must inherit directly or indirectly from object.  In the following, A
and B are classic classes, whereas C and D are new-style classes:

class A: pass

class B(A): pass

class C(object): pass

class D(C): pass

In Python 3, classic classes have been removed, and so all four of the
classes above would be new-style.

> 2. Is the mro function available only on python3?

No, but it is available only on new-style classes.  If you try it on a
classic class, you'll get an AttributeError.

Cheers,
Ian

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Thread

newb __init__ inheritance hyperboogie <hyperboogie@gmail.com> - 2012-03-08 07:25 -0800
  Re: newb __init__ inheritance Maarten <maarten.sneep@knmi.nl> - 2012-03-08 08:30 -0800
    Re: newb __init__ inheritance Peter Otten <__peter__@web.de> - 2012-03-08 18:03 +0100
  Re: newb __init__ inheritance Ethan Furman <ethan@stoneleaf.us> - 2012-03-08 09:34 -0800
  Re: newb __init__ inheritance "Colin J. Williams" <cjw@ncf.ca> - 2012-03-10 12:58 -0500
    Re: newb __init__ inheritance "Colin J. Williams" <cjw@ncf.ca> - 2012-03-10 17:47 -0500
      Re: newb __init__ inheritance hyperboogie <hyperboogie@gmail.com> - 2012-03-11 03:18 -0700
        Re: newb __init__ inheritance Chris Rebert <clp2@rebertia.com> - 2012-03-11 03:38 -0700
          Re: newb __init__ inheritance hyperboogie <hyperboogie@gmail.com> - 2012-03-11 03:56 -0700
            Re: newb __init__ inheritance Chris Rebert <clp2@rebertia.com> - 2012-03-11 04:37 -0700
            Re: newb __init__ inheritance Ian Kelly <ian.g.kelly@gmail.com> - 2012-03-11 05:40 -0600
            Re: newb __init__ inheritance Ian Kelly <ian.g.kelly@gmail.com> - 2012-03-11 05:52 -0600
            Re: newb __init__ inheritance Peter Otten <__peter__@web.de> - 2012-03-11 13:12 +0100
          Re: newb __init__ inheritance hyperboogie <hyperboogie@gmail.com> - 2012-03-11 03:56 -0700
  Re: newb __init__ inheritance hyperboogie <hyperboogie@gmail.com> - 2012-03-12 02:09 -0700

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