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

Groups > comp.lang.python > #85455

Re: __next__ and StopIteration

Date 2015-02-10 08:44 -0800
From Ethan Furman <ethan@stoneleaf.us>
Subject Re: __next__ and StopIteration
References <mailman.18573.1423509383.18130.python-list@python.org> <54d94307$0$12998$c3e8da3$5496439d@news.astraweb.com> <CALwzidnufuFPX1K0QrAJZbEtS79xvOmhM7ZZ8t9dJSiKVvhUqQ@mail.gmail.com> <54D98A35.9060203@earthlink.net> <CAPTjJmrcbOYCuZCgiq9gStEG34nAvQ2gS-vZC-WUuAOPUV3hPw@mail.gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.18615.1423586718.18130.python-list@python.org> (permalink)

Show all headers | View raw

[Multipart message — attachments visible in raw view] - view raw

On 02/09/2015 08:46 PM, Chris Angelico wrote:
> 
> class Grid:
>     blah blah
> 
>     def __iter__(self):
>         for row in range(self._rows):
>             for col in range(self._cols):
>                 if self._grid[row][col]:
>                     yield self._grid[row][col]

I strongly suggest you remove the

  if self._grid[row][col]:

line.

Best case scenario: the entire grid is blank, and iterating through it does nothing.

Worst case scenario:  only some elements evaluate as False, so your loop doesn't execute the full number of times; i.e.
with a grid of 4x5 with 7 blank cells you get 13 iterations -- probably not what was expected.

--
~Ethan~

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

Thread

__next__ and StopIteration Charles Hixson <charleshixsn@earthlink.net> - 2015-02-09 11:14 -0800
  Re: __next__ and StopIteration Rob Gaddi <rgaddi@technologyhighland.invalid> - 2015-02-09 19:27 +0000
  Re: __next__ and StopIteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-10 10:30 +1100
    Re: __next__ and StopIteration Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-09 16:56 -0700
      Re: __next__ and StopIteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-10 11:42 +1100
        Re: __next__ and StopIteration Chris Angelico <rosuav@gmail.com> - 2015-02-10 11:54 +1100
          Re: __next__ and StopIteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-10 12:11 +1100
            Re: __next__ and StopIteration Chris Angelico <rosuav@gmail.com> - 2015-02-10 12:58 +1100
        Re: __next__ and StopIteration Chris Kaynor <ckaynor@zindagigames.com> - 2015-02-09 16:59 -0800
          Re: __next__ and StopIteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-10 16:54 +1100
        Re: __next__ and StopIteration Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-10 01:30 -0700
        Re: __next__ and StopIteration Chris Kaynor <ckaynor@zindagigames.com> - 2015-02-10 09:27 -0800
    Re: __next__ and StopIteration Charles Hixson <charleshixsn@earthlink.net> - 2015-02-09 20:33 -0800
    Re: __next__ and StopIteration Chris Angelico <rosuav@gmail.com> - 2015-02-10 15:46 +1100
    Re: __next__ and StopIteration Charles Hixson <charleshixsn@earthlink.net> - 2015-02-09 22:16 -0800
    Re: __next__ and StopIteration Chris Angelico <rosuav@gmail.com> - 2015-02-10 17:38 +1100
    Re: __next__ and StopIteration Ethan Furman <ethan@stoneleaf.us> - 2015-02-10 08:44 -0800
    Re: __next__ and StopIteration Ian Kelly <ian.g.kelly@gmail.com> - 2015-02-10 09:53 -0700
    Re: __next__ and StopIteration Ethan Furman <ethan@stoneleaf.us> - 2015-02-10 09:33 -0800

csiph-web