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Re: Looking for a good introduction to object oriented programming with Python

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Date Wed, 8 Aug 2012 12:24:02 +1000
Subject Re: Looking for a good introduction to object oriented programming with Python
From Chris Angelico <rosuav@gmail.com>
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On Wed, Aug 8, 2012 at 12:14 PM, Steven D'Aprano
<steve+comp.lang.python@pearwood.info> wrote:
> NoneType raises an error if you try to create a second instance. bool
> just returns one of the two singletons (doubletons?) again.
>
> py> type(None)()
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> TypeError: cannot create 'NoneType' instances
> py> type(False)() is False
> True

This is necessitated by the use of bool(x) as a means of boolifying
("casting to bool", if you like) x. I wouldn't want that to change,
and since type(False) is bool, what you see is bound to occur.

ChrisA

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[newbie] Looking for a good introduction to object oriented programming with Python Jean Dubois <jeandubois314@gmail.com> - 2012-08-04 08:49 -0700
  Re: [newbie] Looking for a good introduction to object oriented programming with Python shearichard@gmail.com - 2012-08-04 17:11 -0700
    Re: Looking for a good introduction to object oriented programming with Python Jean Dubois <jeandubois314@gmail.com> - 2012-08-05 05:38 -0700
    Re: Looking for a good introduction to object oriented programming with Python Jean Dubois <jeandubois314@gmail.com> - 2012-08-05 11:04 -0700
      Re: Looking for a good introduction to object oriented programming with Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-05 19:28 +0100
        Re: Looking for a good introduction to object oriented programming with Python Jean Dubois <jeandubois314@gmail.com> - 2012-08-06 07:56 -0700
          Re: Looking for a good introduction to object oriented programming with Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-06 17:17 +0100
            Re: Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-07 01:12 +0000
              Re: Looking for a good introduction to object oriented programming with Python Ben Finney <ben+python@benfinney.id.au> - 2012-08-07 11:23 +1000
              Re: Looking for a good introduction to object oriented programming with Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-07 08:49 +0100
      Re: Looking for a good introduction to object oriented programming with Python Roy Smith <roy@panix.com> - 2012-08-05 14:39 -0400
      Re: Looking for a good introduction to object oriented programming with Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-05 19:53 +0100
      Re: Looking for a good introduction to object oriented programming with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-05 18:45 -0400
        Re: Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-05 22:51 +0000
          Re: Looking for a good introduction to object oriented programming with Python Roy Smith <roy@panix.com> - 2012-08-05 19:12 -0400
            Re: Looking for a good introduction to object oriented programming with Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-06 00:30 +0100
            Re: Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-06 00:27 +0000
              Re: Looking for a good introduction to object oriented programming with Python Dan Sommers <dan@tombstonezero.net> - 2012-08-05 17:50 -0700
              Re: Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-06 08:48 +0100
              Re: Looking for a good introduction to object oriented programming with Python DJC <djc@news.invalid> - 2012-08-06 11:20 +0200
            Re: Looking for a good introduction to object oriented programming with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-05 20:57 -0400
          Re: Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-06 08:43 +0100
            Re: Looking for a good introduction to object oriented programming with Python Roy Smith <roy@panix.com> - 2012-08-06 09:16 -0400
        Re: Looking for a good introduction to object oriented programming with Python Wolfgang Strobl <news4@mystrobl.de> - 2012-08-06 08:18 +0200
  Re: [newbie] Looking for a good introduction to object oriented programming with Python dncarac@gmail.com - 2012-08-05 11:59 -0700
  Re: [newbie] Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-05 20:46 +0100
    Re: [newbie] Looking for a good introduction to object oriented programming with Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-05 23:11 +0100
      Re: [newbie] Looking for a good introduction to object oriented programming with Python Roy Smith <roy@panix.com> - 2012-08-05 18:53 -0400
    Re: [newbie] Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-06 00:22 +0000
      Re: [newbie] Looking for a good introduction to object oriented programming with Python Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-08-06 02:02 +0100
      Re: [newbie] Looking for a good introduction to object oriented programming with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-05 21:14 -0400
        Re: [newbie] Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-06 06:08 +0000
          Re: [newbie] Looking for a good introduction to object oriented programming with Python Paul Rubin <no.email@nospam.invalid> - 2012-08-06 00:25 -0700
      Re: Looking for a good introduction to object oriented programming with Python alex23 <wuwei23@gmail.com> - 2012-08-05 19:44 -0700
        Re: Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-07 19:02 +0000
          Re: Looking for a good introduction to object oriented programming with Python Terry Reedy <tjreedy@udel.edu> - 2012-08-07 18:37 -0400
          Re: Looking for a good introduction to object oriented programming with Python alex23 <wuwei23@gmail.com> - 2012-08-07 17:07 -0700
            Re: Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-08 02:14 +0000
              Re: Looking for a good introduction to object oriented programming with Python Chris Angelico <rosuav@gmail.com> - 2012-08-08 12:24 +1000
              Re: Looking for a good introduction to object oriented programming with Python alex23 <wuwei23@gmail.com> - 2012-08-07 20:20 -0700
      Re: [newbie] Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-06 09:55 +0100
        Re: [newbie] Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-06 10:24 +0100
          Re: [newbie] Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-07 05:35 +0000
            Re: [newbie] Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-07 09:16 +0100
        Re: [newbie] Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-07 05:19 +0000
          Re: [newbie] Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-07 10:19 +0100
            Re: [newbie] Looking for a good introduction to object oriented programming with Python Ben Finney <ben+python@benfinney.id.au> - 2012-08-07 23:12 +1000
              Re: [newbie] Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-07 15:13 +0100
            Re: [newbie] Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-07 14:14 +0000
              Re: [newbie] Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-07 15:34 +0100
                Re: Looking for a good introduction to object oriented programming with Python rusi <rustompmody@gmail.com> - 2012-08-07 08:04 -0700
                Re: Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-07 18:00 +0100
                Re: Looking for a good introduction to object oriented programming with Python Chris Angelico <rosuav@gmail.com> - 2012-08-08 07:57 +1000
                Re: Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-08 10:51 +0100
                Re: Looking for a good introduction to object oriented programming with Python rusi <rustompmody@gmail.com> - 2012-08-08 09:27 -0700
                Re: Looking for a good introduction to object oriented programming with Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-08 17:28 +0000
                Re: Looking for a good introduction to object oriented programming with Python Chris Angelico <rosuav@gmail.com> - 2012-08-09 11:32 +1000
                Re: Looking for a good introduction to object oriented programming with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-08 12:42 -0400
                Re: Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-08 20:31 +0100
                Re: Looking for a good introduction to object oriented programming with Python Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2012-08-08 22:59 -0400
                Re: Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-09 08:29 +0100
                Geneology Packages -- WAS: Looking for a good introduction to object oriented programming with Python Simon Cropper <simoncropper@fossworkflowguides.com> - 2012-08-09 13:51 +1000
                Re: Geneology Packages Ben Finney <ben+python@benfinney.id.au> - 2012-08-09 14:00 +1000
    Re: Looking for a good introduction to object oriented programming with Python rusi <rustompmody@gmail.com> - 2012-08-06 05:19 -0700
      Re: Looking for a good introduction to object oriented programming with Python lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-06 15:27 +0100
        Re: Looking for a good introduction to object oriented programming with Python rusi <rustompmody@gmail.com> - 2012-08-06 09:34 -0700
          Re: Looking for a good introduction to object oriented programming with Python Chris Angelico <rosuav@gmail.com> - 2012-08-07 08:44 +1000
      OT probably but still relevant (was Re: Looking for a good introduction to object oriented programming with Python) lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-06 17:23 +0100
        Re: OT probably but still relevant (was Re: Looking for a good introduction to object oriented programming with Python) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-07 09:44 +0000
          Re: OT probably but still relevant (was Re: Looking for a good introduction to object oriented programming with Python) lipska the kat <lipskathekat@yahoo.co.uk> - 2012-08-07 11:23 +0100

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