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Re: Lucky numbers in Python

References <87lhhabxod.fsf@Equus.decebal.nl>
From Ian Kelly <ian.g.kelly@gmail.com>
Date 2015-04-29 13:57 -0600
Subject Re: Lucky numbers in Python
Newsgroups comp.lang.python
Message-ID <mailman.95.1430337506.3680.python-list@python.org> (permalink)

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On Wed, Apr 29, 2015 at 12:24 PM, Cecil Westerhof <Cecil@decebal.nl> wrote:
> I was wondering if there is a way to do this:
>             for del_index in range((sieve_len // skip_count) * skip_count - 1,
>                                   skip_count - 2, -skip_count):
>                 del sieve[del_index]
> in a more efficient way.

You can delete using slices.

del sieve[(sieve_len // skip_count) * skip_count - 1 : skip_count - 2
: -skip_count]

Now you no longer need to do the iteration in reverse, which makes the
slicing simpler:

del sieve[skip_count - 1 : (sieve_len // skip_count) * skip_count : skip_count]

And although it's not clear to me what this is supposed to be doing,
you probably no longer need the middle term if the intention is to
continue deleting all the way to the end of the list (if it is then I
think you have a bug in the existing implementation, since the last
item in the list can never be deleted).

del sieve[skip_count - 1 :: skip_count]

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Thread

Lucky numbers in Python Cecil Westerhof <Cecil@decebal.nl> - 2015-04-29 20:24 +0200
  Re: Lucky numbers in Python Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-29 13:57 -0600
    Re: Lucky numbers in Python Cecil Westerhof <Cecil@decebal.nl> - 2015-04-29 23:45 +0200
      Re: Lucky numbers in Python Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-29 16:38 -0600
        Re: Lucky numbers in Python Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 02:01 +0200
          Re: Lucky numbers in Python Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-29 20:55 -0600
            Re: Lucky numbers in Python Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 08:34 +0200
      Re: Lucky numbers in Python Chris Kaynor <ckaynor@zindagigames.com> - 2015-04-29 15:56 -0700
    Re: Lucky numbers in Python Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-04-30 10:11 +1000
      Re: Lucky numbers in Python Ian Kelly <ian.g.kelly@gmail.com> - 2015-04-29 21:08 -0600
  Re: Lucky numbers in Python Cecil Westerhof <Cecil@decebal.nl> - 2015-04-30 20:55 +0200
    Re: Lucky numbers in Python Dave Angel <davea@davea.name> - 2015-04-30 15:28 -0400

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