Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > comp.lang.python > #92574

Re: zip as iterator and bad/good practices

Newsgroups comp.lang.python
Date 2015-06-12 17:39 -0700
References <mles66$sk2$1@speranza.aioe.org> <201506122034.t5CKYYt0025588@fido.openend.se> <mailman.447.1434152635.13271.python-list@python.org> <e5d750bd-d7e3-4d93-9794-e9f16a4b40bd@googlegroups.com> <mailman.450.1434155212.13271.python-list@python.org>
Message-ID <df28e29a-cbc9-48b9-bf30-8b1f311848c2@googlegroups.com> (permalink)
Subject Re: zip as iterator and bad/good practices
From sohcahtoa82@gmail.com

Show all headers | View raw


On Friday, June 12, 2015 at 5:27:21 PM UTC-7, Chris Angelico wrote:
> On Sat, Jun 13, 2015 at 10:02 AM,  <sohcahtoa82@gmail.com> wrote:
> >>  >>> ints = [0, 1, 2, 2, 1, 4, 6, 5, 5]
> >>  >>> ints[:] = [i for i in ints if not i % 2]
> >>  >>> ints
> >> [0, 2, 2, 4, 6]
> >>
> >>
> >> --
> >> Terry Jan Reedy
> >
> > On the second line of your final solution, is there any reason you're using `ints[:]` rather than just `ints`?
> 
> If you use "ints = [...]", it rebinds the name ints to the new list.
> If you use "ints[:] = [...]", it replaces the entire contents of the
> list with the new list. The two are fairly similar if there are no
> other references to that list, but the replacement matches the
> mutation behaviour of remove().
> 
> def just_some(ints):
>     ints[:] = [i for i in ints if not i % 2]
> 
> ChrisA

Ah that makes sense.  Thanks.

Back to comp.lang.python | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

zip as iterator and bad/good practices Fabien <fabien.maussion@gmail.com> - 2015-06-12 17:00 +0200
  Re: zip as iterator and bad/good practices Fabien <fabien.maussion@gmail.com> - 2015-06-12 17:05 +0200
  Re: zip as iterator and bad/good practices Ian Kelly <ian.g.kelly@gmail.com> - 2015-06-12 09:26 -0600
    Re: zip as iterator and bad/good practices Fabien <fabien.maussion@gmail.com> - 2015-06-12 17:34 +0200
    Re: zip as iterator and bad/good practices Fabien <fabien.maussion@gmail.com> - 2015-06-12 17:59 +0200
  Re: zip as iterator and bad/good practices Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-06-12 17:22 +0100
  Re: zip as iterator and bad/good practices Laura Creighton <lac@openend.se> - 2015-06-12 22:34 +0200
  Re: zip as iterator and bad/good practices Terry Reedy <tjreedy@udel.edu> - 2015-06-12 19:27 -0400
  Re: zip as iterator and bad/good practices Terry Reedy <tjreedy@udel.edu> - 2015-06-12 19:43 -0400
    Re: zip as iterator and bad/good practices sohcahtoa82@gmail.com - 2015-06-12 17:02 -0700
      Re: zip as iterator and bad/good practices Chris Angelico <rosuav@gmail.com> - 2015-06-13 10:26 +1000
        Re: zip as iterator and bad/good practices sohcahtoa82@gmail.com - 2015-06-12 17:39 -0700
  Re: zip as iterator and bad/good practices jimages <jimages123@gmail.com> - 2015-06-13 13:32 +0800
    Re: zip as iterator and bad/good practices Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-06-13 07:17 +0000
      Re: zip as iterator and bad/good practices Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2015-06-13 13:48 +0100
        Re: zip as iterator and bad/good practices Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-06-13 16:16 +0000

csiph-web