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Re: Assignment Versus Equality

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From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Subject Re: Assignment Versus Equality
Date Wed, 29 Jun 2016 23:34:48 +1000
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On Wed, Jun 29, 2016 at 10:36 PM, Steven D'Aprano <steve@pearwood.info> wrote:
>> rosuav@sikorsky:~$ python2.7 -m timeit -s "n = 0" "for i in
>> xrange(10000): n += i"
>> 10000 loops, best of 3: 192 usec per loop
>> rosuav@sikorsky:~$ python2.7 -m timeit -s "n = 1<<100" "for i in
>> xrange(10000): n += i"
>> 1000 loops, best of 3: 478 usec per loop
>
> Now *that's* an unfair benchmark, because we know that BigNums get slower as
> they get bigger. A BigNum with 30+ digits is not going to perform like a
> BigNum with 8 digits.

On its own, perhaps. But then I do the exact same tests on Python 3,
and the numbers are virtually identical - suggesting that the bignum
slowdown isn't all that significant at all. But in case you're
worried, I'll do it your way too:

rosuav@sikorsky:~$ python2.7 -m timeit -s "n = 0" "for i in
xrange(10000): n += i"
10000 loops, best of 3: 192 usec per loop
rosuav@sikorsky:~$ python2.7 -m timeit -s "n = 1<<100" "for i in
xrange(10000): n += i"
1000 loops, best of 3: 476 usec per loop
rosuav@sikorsky:~$ python2.7 -m timeit -s "n = 0L" "for i in
xrange(10000): n += i"
1000 loops, best of 3: 476 usec per loop

So, once again, my system shows that there's a definite slowdown from
using bignums - and it's the same whether I start with 1<<100 or 0L.
(In this particular run, absolutely precisely the same, but other runs
showed numbers like 479 and 486.) What's different about your system
that you see short ints as performing exactly the same as long ints?
Obviously you're running on a slower computer than mine (you're seeing
msec values compared to my usec), but that shouldn't be significant.
Is there a massive architectural difference?

rosuav@sikorsky:~$ uname -a
Linux sikorsky 4.6.0-1-amd64 #1 SMP Debian 4.6.1-1 (2016-06-06) x86_64 GNU/Linux

ChrisA

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Thread

Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-26 00:36 -0700
  Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-26 11:48 +0100
    Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-26 23:21 +1000
      Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-26 07:26 -0700
        Re: Assignment Versus Equality Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-06-26 11:31 -0400
      Re: Assignment Versus Equality Christopher Reimer <christopher_reimer@icloud.com> - 2016-06-26 11:47 -0700
      Re: Assignment Versus Equality Michael Torrie <torriem@gmail.com> - 2016-06-26 15:28 -0600
      Re: Assignment Versus Equality Bob Gailer <bgailer@gmail.com> - 2016-06-27 08:22 -0400
        Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-27 05:48 -0700
          Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-27 23:28 +1000
            Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 16:58 +0300
            Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-27 07:23 -0700
              Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-28 11:05 +1000
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-27 21:31 -0700
                Re: Assignment Versus Equality Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-28 15:42 +1000
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-28 16:04 +1000
                Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 09:12 +0300
                Re: Assignment Versus Equality Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-28 11:04 +0300
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-27 23:09 -0700
                Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-28 00:12 -0700
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-28 17:26 +1000
                Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-28 01:49 -0700
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-28 20:34 +1000
                Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-28 17:42 -0700
                Re: Assignment Versus Equality Random832 <random832@fastmail.com> - 2016-06-28 10:13 -0400
                Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 19:39 +0300
                Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 19:41 +0300
                Re: Assignment Versus Equality Random832 <random832@fastmail.com> - 2016-06-28 13:19 -0400
                Re: Assignment Versus Equality Ian Kelly <ian.g.kelly@gmail.com> - 2016-06-28 12:27 -0600
                Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 22:40 +0300
                Re: Assignment Versus Equality Gene Heskett <gheskett@shentel.net> - 2016-06-28 16:59 -0400
                Re: Assignment Versus Equality Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-30 12:29 +1200
                Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-30 12:50 +1000
                Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-30 09:22 +0300
                Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-29 12:27 +1000
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-28 20:52 -0700
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-28 21:03 -0700
                Re: Assignment Versus Equality Random832 <random832@fastmail.com> - 2016-06-29 00:52 -0400
              Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-27 18:14 -0700
            Re: Assignment Versus Equality Gene Heskett <gheskett@shentel.net> - 2016-06-27 11:21 -0400
          Re: Assignment Versus Equality Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-06-27 20:04 -0400
    Re: Assignment Versus Equality Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-06-26 11:21 -0400
      Re: Assignment Versus Equality Cousin Stanley <HooDunnit@didly42KahZidly.net> - 2016-06-26 08:47 -0700
        Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-26 16:56 +0100
          Re: Assignment Versus Equality Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-27 11:38 +1200
          Re: Assignment Versus Equality Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-06-27 07:30 -0400
            Re: Assignment Versus Equality Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-28 18:17 +1200
          Re: Assignment Versus Equality Grant Edwards <grant.b.edwards@gmail.com> - 2016-06-27 13:59 +0000
            Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-27 17:09 +0300
              Re: Assignment Versus Equality sohcahtoa82@gmail.com - 2016-06-27 17:33 -0700
                Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-28 07:25 +0300
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-27 23:54 -0700
            Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-27 07:10 -0700
              Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-29 12:35 +1000
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-29 14:19 +1000
                Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-28 21:51 -0700
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-29 15:07 +1000
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-28 22:55 -0700
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-29 16:26 +1000
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-28 23:33 -0700
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-28 23:37 -0700
                Re: Assignment Versus Equality Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-29 15:26 +1000
                Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-28 22:51 -0700
                Re: Assignment Versus Equality Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2016-06-29 16:45 +1000
                Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-29 01:07 -0700
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-29 18:09 +1000
                Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-29 22:36 +1000
                Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-29 14:24 +0100
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-29 23:35 +1000
                Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-29 15:47 +0100
                Re: Assignment Versus Equality Chris Angelico <rosuav@gmail.com> - 2016-06-29 23:34 +1000
                Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-29 10:49 +0100
                Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-29 02:56 -0700
                Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-29 11:10 +0100
                Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-29 03:24 -0700
            Re: Assignment Versus Equality Alain Ketterlin <alain@universite-de-strasbourg.fr.invalid> - 2016-06-27 16:48 +0200
              Re: Assignment Versus Equality Rustom Mody <rustompmody@gmail.com> - 2016-06-27 22:00 -0700
            Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-28 11:34 +1000
          Re: Assignment Versus Equality MRAB <python@mrabarnett.plus.com> - 2016-06-27 16:27 +0100
            Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-27 14:56 -0700
            Re: Assignment Versus Equality Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-27 15:45 -0700
              Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-28 00:08 +0100
                Re: Assignment Versus Equality Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2016-06-27 20:11 -0400
                Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-28 11:35 +0100
                Re: Assignment Versus Equality Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-28 18:59 +1200
            Re: Assignment Versus Equality Steven D'Aprano <steve@pearwood.info> - 2016-06-28 11:28 +1000
          Re: Assignment Versus Equality Grant Edwards <grant.b.edwards@gmail.com> - 2016-06-27 15:42 +0000
      Re: Assignment Versus Equality Marko Rauhamaa <marko@pacujo.net> - 2016-06-26 19:11 +0300
    Re: Assignment Versus Equality MRAB <python@mrabarnett.plus.com> - 2016-06-26 16:41 +0100
      Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-26 17:08 +0100
    Re: Assignment Versus Equality Christopher Reimer <christopher_reimer@icloud.com> - 2016-06-26 11:53 -0700
      Re: Assignment Versus Equality Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-27 11:41 +1200
    Re: Assignment Versus Equality Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-27 11:22 +1200
      Re: Assignment Versus Equality BartC <bc@freeuk.com> - 2016-06-27 00:39 +0100
        Re: Assignment Versus Equality Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2016-06-28 18:15 +1200

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