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Re: Strange range

From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Subject Re: Strange range
Date 2016-04-02 01:31 +1100
Message-ID <mailman.311.1459521083.28225.python-list@python.org> (permalink)
References <87y48xjwqq.fsf@elektro.pacujo.net> <56fe76f2$0$22141$c3e8da3$5496439d@news.astraweb.com> <ndlvrt$1hlp$1@gioia.aioe.org>

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On Sat, Apr 2, 2016 at 1:16 AM, Fabien <fabien.maussion@gmail.com> wrote:
> On 04/01/2016 03:26 PM, Steven D'Aprano wrote:
>>
>> Incorrect. range is a lazy sequence.
>
>
> But how does range "know" that it has to start from scratch again? As in
> this example:
>
> it = range(10)
> for i in it:
>     if i >= 3:
>         break
> for i in it:
>     # why does it start from zero again?
>     print(i)

It's not an iterator. It's an iterable. So every time you call iter()
on it - which is done implicitly by the starting of the 'for' loop -
you get a completely new iterator which will step through the whole
range object.

*A range object is not an iterator.*

ChrisA

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Thread

Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-01 16:15 +0300
  Re: Strange range Chris Angelico <rosuav@gmail.com> - 2016-04-02 00:24 +1100
  Re: Strange range Steven D'Aprano <steve@pearwood.info> - 2016-04-02 00:26 +1100
    Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-01 17:12 +0300
      Re: Strange range Random832 <random832@fastmail.com> - 2016-04-01 10:39 -0400
    Re: Strange range Fabien <fabien.maussion@gmail.com> - 2016-04-01 16:16 +0200
      Re: Strange range Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-04-01 17:28 +0300
      Re: Strange range Chris Angelico <rosuav@gmail.com> - 2016-04-02 01:31 +1100
        Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-01 17:34 +0300
          Re: Strange range Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-04-01 17:44 +0300
          Re: Strange range Chris Angelico <rosuav@gmail.com> - 2016-04-02 01:45 +1100
            Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-01 18:43 +0300
          Re: Strange range Erik <python@lucidity.plus.com> - 2016-04-01 20:58 +0100
            Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-01 23:14 +0300
              Re: Strange range Rob Gaddi <rgaddi@highlandtechnology.invalid> - 2016-04-01 20:21 +0000
                Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-01 23:44 +0300
              Re: Strange range Steven D'Aprano <steve@pearwood.info> - 2016-04-02 21:09 +1100
                Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-02 13:48 +0300
          Re: Strange range Ned Batchelder <ned@nedbatchelder.com> - 2016-04-02 12:47 -0700
            Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-02 23:44 +0300
              Re: Strange range Chris Angelico <rosuav@gmail.com> - 2016-04-03 07:05 +1000
                Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-03 00:40 +0300
                Re: Strange range Ned Batchelder <ned@nedbatchelder.com> - 2016-04-02 14:50 -0700
                Re: Strange range Stephen Hansen <me+python@ixokai.io> - 2016-04-02 23:43 -0700
                Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-03 09:58 +0300
                Re: Strange range Chris Angelico <rosuav@gmail.com> - 2016-04-03 17:10 +1000
                Re: Strange range Ethan Furman <ethan@stoneleaf.us> - 2016-04-03 09:28 -0700
                Re: Strange range Mark Lawrence <breamoreboy@yahoo.co.uk> - 2016-04-04 13:21 +0100
                Re: Strange range Chris Angelico <rosuav@gmail.com> - 2016-04-03 17:08 +1000
              Re: Strange range Steven D'Aprano <steve@pearwood.info> - 2016-04-03 14:43 +1000
                Re: Strange range Random832 <random832@fastmail.com> - 2016-04-03 01:20 -0400
                Re: Strange range Steven D'Aprano <steve@pearwood.info> - 2016-04-03 15:28 +1000
      Re: Strange range Marko Rauhamaa <marko@pacujo.net> - 2016-04-01 17:32 +0300
  Re: Strange range Random832 <random832@fastmail.com> - 2016-04-01 10:42 -0400
  Re: Strange range Chris Angelico <rosuav@gmail.com> - 2016-04-02 01:50 +1100
  Re: Strange range Ian Kelly <ian.g.kelly@gmail.com> - 2016-04-01 08:52 -0600

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