Re: l = range(int(1E9))

References	(5 earlier) <_M61x.477467$Ek.357048@fx07.am4> <mailman.15.1430584786.12865.python-list@python.org> <bN81x.386497$G53.218869@fx13.am4> <mailman.23.1430594149.12865.python-list@python.org> <CV91x.402510$zE7.111881@fx40.am4>
From	Ian Kelly <ian.g.kelly@gmail.com>
Date	2015-05-02 15:31 -0600
Subject	Re: l = range(int(1E9))
Newsgroups	comp.lang.python
Message-ID	<mailman.29.1430602350.12865.python-list@python.org> (permalink)

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On Sat, May 2, 2015 at 1:51 PM, BartC <bc@freeuk.com> wrote:
> On 02/05/2015 20:15, Mark Lawrence wrote:
>>
>> On 02/05/2015 19:34, BartC wrote:
>
>
>>> OK, so it's the programmer's fault if as fundamental a concept as a
>>> for-loop ranging over integers is implemented inefficiently. He has to
>>> transform it into high-level terms, or has to reconstruct it somehow
>>> using a while-loop and an incrementing loop index.
>
>
>> I give up.
>
>
> So do I, I think, if no-one is willing to admit that the original way of
> implementing range() was a glaring mistake.

range() was and is a *convenience* function. In the real world, the
vast majority of for loops are over arrays or other containers, not
integers, and those that aren't are usually very small. In non-toy
code, using a for loop to count to a billion is highly unusual.

So yeah, for a programmer porting code to Python who needed to loop
over an array, the correct approach would be to actually loop over the
*array* in place of the indices of the array. I don't know why you
make this out to be such a big deal; it's a simple conversion.

Would it have been better if range() had been implemented as xrange()
from the beginning? Sure, that would have been great. Except for one
small detail: the iterator protocol didn't exist back then. That
wasn't introduced until PEP 234 in Python 2.1, which means that the
xrange() function wasn't even *possible* before then.

I don't think anybody would claim that Python was perfect when it was
first introduced (nor is it perfect now). Like all other software, it
has improved over time as a result of iterative refinement.

Thread

l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 18:06 +0200
  Re: l = range(int(1E9)) Grant Edwards <invalid@invalid.invalid> - 2015-04-30 16:33 +0000
    Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 19:26 +0200
      Re: l = range(int(1E9)) Ben Finney <ben+python@benfinney.id.au> - 2015-05-01 03:41 +1000
        Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 20:44 +0200
    Re: l = range(int(1E9)) Roel Schroeven <roel@roelschroeven.net> - 2015-04-30 21:40 +0200
  Re: l = range(int(1E9)) Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-04-30 16:55 +0000
    Re: l = range(int(1E9)) Ben Finney <ben+python@benfinney.id.au> - 2015-05-01 03:20 +1000
      Re: l = range(int(1E9)) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-01 15:20 +1000
        Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-05-01 08:08 +0200
      Re: l = range(int(1E9)) BartC <bc@freeuk.com> - 2015-05-02 16:26 +0100
        Re: l = range(int(1E9)) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-05-02 16:40 +0100
          Re: l = range(int(1E9)) BartC <bc@freeuk.com> - 2015-05-02 17:17 +0100
            Re: l = range(int(1E9)) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-05-02 17:39 +0100
              Re: l = range(int(1E9)) BartC <bc@freeuk.com> - 2015-05-02 19:34 +0100
                Re: l = range(int(1E9)) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-05-02 20:15 +0100
                Re: l = range(int(1E9)) Marko Rauhamaa <marko@pacujo.net> - 2015-05-02 22:26 +0300
                Re: l = range(int(1E9)) BartC <bc@freeuk.com> - 2015-05-02 20:51 +0100
                Re: l = range(int(1E9)) Joel Goldstick <joel.goldstick@gmail.com> - 2015-05-02 17:21 -0400
                Re: l = range(int(1E9)) Ian Kelly <ian.g.kelly@gmail.com> - 2015-05-02 15:31 -0600
                Re: l = range(int(1E9)) Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-05-02 21:40 +0000
                Re: l = range(int(1E9)) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-05-02 23:26 +0100
                Re: l = range(int(1E9)) BartC <bc@freeuk.com> - 2015-05-02 23:33 +0100
                Re: l = range(int(1E9)) Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-05-03 00:13 +0000
                Re: l = range(int(1E9)) Michael Torrie <torriem@gmail.com> - 2015-05-02 20:07 -0600
                Re: l = range(int(1E9)) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-05-03 03:16 +0100
                Re: l = range(int(1E9)) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-03 21:16 +1000
                Re: l = range(int(1E9)) Chris Angelico <rosuav@gmail.com> - 2015-05-03 21:30 +1000
                Re: l = range(int(1E9)) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-05-03 19:36 +0100
                Re: l = range(int(1E9)) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-03 21:15 +1000
                Re: l = range(int(1E9)) Chris Angelico <rosuav@gmail.com> - 2015-05-03 21:29 +1000
                Re: l = range(int(1E9)) Terry Reedy <tjreedy@udel.edu> - 2015-05-02 19:26 -0400
                Re: l = range(int(1E9)) Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-05-03 00:01 +0000
                Re: l = range(int(1E9)) Terry Reedy <tjreedy@udel.edu> - 2015-05-02 23:18 -0400
                Re: l = range(int(1E9)) Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-05-03 03:40 +0000
                Re: l = range(int(1E9)) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-03 21:05 +1000
                Re: l = range(int(1E9)) Terry Reedy <tjreedy@udel.edu> - 2015-05-02 19:51 -0400
                Re: l = range(int(1E9)) Ian Kelly <ian.g.kelly@gmail.com> - 2015-05-02 22:51 -0600
                Re: l = range(int(1E9)) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-03 21:21 +1000
                Re: l = range(int(1E9)) Marko Rauhamaa <marko@pacujo.net> - 2015-05-02 22:15 +0300
            Re: l = range(int(1E9)) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-03 20:32 +1000
              Re: l = range(int(1E9)) Chris Angelico <rosuav@gmail.com> - 2015-05-03 20:59 +1000
        Re: l = range(int(1E9)) Terry Reedy <tjreedy@udel.edu> - 2015-05-02 18:41 -0400
    Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 19:28 +0200
  Re: l = range(int(1E9)) Terry Reedy <tjreedy@udel.edu> - 2015-04-30 13:02 -0400
  Re: l = range(int(1E9)) Gary Herron <gherron@digipen.edu> - 2015-04-30 10:05 -0700
    Re: l = range(int(1E9)) Rob Gaddi <rgaddi@technologyhighland.invalid> - 2015-04-30 17:12 +0000
      Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 20:50 +0200
        Re: l = range(int(1E9)) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-04-30 21:53 +0100
          Re: l = range(int(1E9)) ElChino <elchino@cnn.cn> - 2015-04-30 23:23 +0200
            Re: l = range(int(1E9)) Chris Angelico <rosuav@gmail.com> - 2015-05-01 08:45 +1000
              Re: l = range(int(1E9)) ElChino <elchino@cnn.cn> - 2015-05-01 01:03 +0200
            Re: l = range(int(1E9)) Ben Finney <ben+python@benfinney.id.au> - 2015-05-01 09:12 +1000
              Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-05-01 07:04 +0200
                Re: l = range(int(1E9)) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-05-01 13:15 +0200
                Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-05-01 14:22 +0200
                Re: l = range(int(1E9)) Terry Reedy <tjreedy@udel.edu> - 2015-05-01 22:00 -0400
            Use ‘python2’ or ‘python3’, explicit is better than implicit  (was: l = range(int(1E9))) Ben Finney <ben+python@benfinney.id.au> - 2015-05-01 09:19 +1000
              Re: Use 'python2' or 'python3', explicit is better than implicit  (was: l = range(int(1E9))) Rustom Mody <rustompmody@gmail.com> - 2015-04-30 19:24 -0700
            Re: l = range(int(1E9)) Chris Angelico <rosuav@gmail.com> - 2015-05-01 09:23 +1000
          Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-05-01 06:19 +0200
            Re: l = range(int(1E9)) Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-05-01 05:41 +0100
            Re: l = range(int(1E9)) Michael Torrie <torriem@gmail.com> - 2015-05-01 07:25 -0600
              Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-05-01 16:12 +0200
  Re: l = range(int(1E9)) Gisle Vanem <gvanem@yahoo.no> - 2015-04-30 20:23 +0200
    Re: l = range(int(1E9)) alister <alister.nospam.ware@ntlworld.com> - 2015-04-30 18:48 +0000
      Re: l = range(int(1E9)) Dave Angel <davea@davea.name> - 2015-04-30 14:59 -0400
        Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 22:18 +0200
          Re: l = range(int(1E9)) Tim Chase <python.list@tim.thechases.com> - 2015-04-30 16:41 -0500
            Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-05-01 07:19 +0200
  Re: l = range(int(1E9)) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-01 14:42 +1000
    Re: l = range(int(1E9)) Cecil Westerhof <Cecil@decebal.nl> - 2015-05-01 07:13 +0200
    Re: l = range(int(1E9)) Tony the Tiger <tony@tiger.invalid> - 2015-05-02 21:28 +0000
      Re: l = range(int(1E9)) Ian Kelly <ian.g.kelly@gmail.com> - 2015-05-02 15:32 -0600
      Re: l = range(int(1E9)) Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-05-03 20:56 +1000

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