Re: can't add variables to instances of built-in classes

From	Chris Angelico <rosuav@gmail.com>
Newsgroups	comp.lang.python
Subject	Re: can't add variables to instances of built-in classes
Date	2016-07-17 22:02 +1000
Message-ID	<mailman.64.1468756954.2307.python-list@python.org> (permalink)
References	<4f796d95-0e87-4610-a0a8-1eff07c60ace@googlegroups.com> <nmfqrg$ea7$1@ger.gmane.org> <mailman.63.1468755660.2307.python-list@python.org> <b24bede0-be29-4c45-856e-90e6a63c99d0@googlegroups.com> <CAPTjJmphwsCYJUvz-D5p048WFWoJ-cJsi3U0Xbg0SuNK8pY7aQ@mail.gmail.com>

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On Sun, Jul 17, 2016 at 9:50 PM, Wilson Ong <wilsonokw@gmail.com> wrote:
>> Use this feature sparingly, only when you know that there are going to be
>> many (millions rather than thousands) of Test instances.
>
> Why use it sparingly? Is it for extensibility? What if I'm pretty sure that my class is going to have exactly these attributes only?

"Pretty sure" isn't enough justification for a relatively meagre
saving of memory. Much easier to leave it flexible. It's only once the
memory saving stops being "relatively meagre" (for instance, with the
built-in 'str' type - there are a LOT of strings in a Python program,
since your variable names are stored as strings) that it's worth doing
that.

ChrisA

Thread

can't add variables to instances of built-in classes Kent Tong <kent.tong.mo@gmail.com> - 2016-07-17 03:57 -0700
  Re: can't add variables to instances of built-in classes Peter Otten <__peter__@web.de> - 2016-07-17 13:40 +0200
    Re: can't add variables to instances of built-in classes Wilson Ong <wilsonokw@gmail.com> - 2016-07-17 04:50 -0700
      Re: can't add variables to instances of built-in classes Chris Angelico <rosuav@gmail.com> - 2016-07-17 22:02 +1000
      Re: can't add variables to instances of built-in classes Steven D'Aprano <steve@pearwood.info> - 2016-07-18 01:04 +1000
        Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-17 20:00 -0700
          Re: can't add variables to instances of built-in classes Peter Otten <__peter__@web.de> - 2016-07-18 09:38 +0200
            Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-18 14:48 -0700
              Re: can't add variables to instances of built-in classes breamoreboy@gmail.com - 2016-07-18 16:12 -0700
                Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-18 19:53 -0700
                Re: can't add variables to instances of built-in classes breamoreboy@gmail.com - 2016-07-19 14:24 -0700
                Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-19 16:58 -0700
                Re: can't add variables to instances of built-in classes Chris Angelico <rosuav@gmail.com> - 2016-07-20 16:19 +1000
                Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-19 23:45 -0700
                Re: can't add variables to instances of built-in classes Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-07-20 17:22 +1000
                Re: can't add variables to instances of built-in classes Peter Otten <__peter__@web.de> - 2016-07-20 09:26 +0200
                Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-20 01:50 -0700
                Re: can't add variables to instances of built-in classes Peter Otten <__peter__@web.de> - 2016-07-20 11:15 +0200
                Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-20 15:11 -0700
                Re: can't add variables to instances of built-in classes Chris Angelico <rosuav@gmail.com> - 2016-07-21 12:29 +1000
                Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-08-03 19:34 -0700
                Re: can't add variables to instances of built-in classes Chris Angelico <rosuav@gmail.com> - 2016-08-04 13:00 +1000
                Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-08-04 16:57 -0700
                Re: can't add variables to instances of built-in classes Steven D'Aprano <steve@pearwood.info> - 2016-07-21 12:48 +1000
                Re: can't add variables to instances of built-in classes Steven D'Aprano <steve@pearwood.info> - 2016-07-20 22:10 +1000
                Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-20 14:48 -0700
                Re: can't add variables to instances of built-in classes breamoreboy@gmail.com - 2016-07-20 18:04 -0700
                Re: can't add variables to instances of built-in classes Peter Otten <__peter__@web.de> - 2016-07-21 08:59 +0200
              Re: can't add variables to instances of built-in classes Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-07-20 02:10 -0700
      Re: can't add variables to instances of built-in classes Ethan Furman <ethan@stoneleaf.us> - 2016-07-18 06:10 -0700
  Re: can't add variables to instances of built-in classes Kent Tong <kent.tong.mo@gmail.com> - 2016-07-17 04:53 -0700

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