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Groups > comp.lang.python > #30423

Re: data attributes override method attributes?

From Terry Reedy <tjreedy@udel.edu>
Subject Re: data attributes override method attributes?
Date 2012-09-28 14:26 -0400
References (4 earlier) <CAPTjJmo9A2_0hjy2RJW+ALAvd4CTmUfOfh8sy7LspSJxdiWPgw@mail.gmail.com> <k3t2di$9f6$1@ger.gmane.org> <CALwzidk+8BftxXffxidEBZn9xwq6bDMAcTa81HYpq8jGfE=BqA@mail.gmail.com> <k3t4gj$ral$1@ger.gmane.org> <5B80DD153D7D744689F57F4FB69AF474166CCB67@SCACMX008.exchad.jpmchase.net>
Newsgroups comp.lang.python
Message-ID <mailman.1578.1348856800.27098.python-list@python.org> (permalink)

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On 9/28/2012 2:02 PM, Prasad, Ramit wrote:

> Just to make sure I am following, if you call
> foo.__len__() it goes to the instance code while
> if you do len(foo) it will go to class.__len__()?

len(foo) calls someclass.__len__(foo) where someclass is foo.__class__or 
some superclass.

> If so, why?

Efficiency and perhaps simpler implementation, especially for binary ops.

-- 
Terry Jan Reedy

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Thread

data attributes override method attributes? Jayden <jayden.shui@gmail.com> - 2012-09-25 06:41 -0700
  Re: data attributes override method attributes? alex23 <wuwei23@gmail.com> - 2012-09-25 06:52 -0700
  Re: data attributes override method attributes? Peter Otten <__peter__@web.de> - 2012-09-25 16:08 +0200
    Re: data attributes override method attributes? alex23 <wuwei23@gmail.com> - 2012-09-25 07:11 -0700
      Re: data attributes override method attributes? Peter Otten <__peter__@web.de> - 2012-09-25 16:54 +0200
      Re: data attributes override method attributes? Chris Angelico <rosuav@gmail.com> - 2012-09-26 01:03 +1000
      Re: data attributes override method attributes? Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> - 2012-09-25 16:54 +0200
      Re: data attributes override method attributes? Terry Reedy <tjreedy@udel.edu> - 2012-09-25 15:58 -0400
      Re: data attributes override method attributes? Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-25 14:07 -0600
      Re: data attributes override method attributes? Terry Reedy <tjreedy@udel.edu> - 2012-09-25 16:18 -0400
      Re: data attributes override method attributes? Terry Reedy <tjreedy@udel.edu> - 2012-09-25 16:34 -0400
      RE: data attributes override method attributes? "Prasad, Ramit" <ramit.prasad@jpmorgan.com> - 2012-09-28 18:02 +0000
        Re: data attributes override method attributes? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-29 03:20 +0000
      Re: data attributes override method attributes? Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-28 12:25 -0600
      Re: data attributes override method attributes? Terry Reedy <tjreedy@udel.edu> - 2012-09-28 14:26 -0400
    Re: data attributes override method attributes? Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-09-25 21:52 +0200
  Re: data attributes override method attributes? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-25 14:12 +0000

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