Re: Lucky numbers in Python

Path	csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!1.eu.feeder.erje.net!news2.arglkargh.de!newsfeed.fsmpi.rwth-aachen.de!newsfeed.straub-nv.de!newsfeed.pionier.net.pl!feed.xsnews.nl!border03.ams.xsnews.nl!feeder04.ams.xsnews.nl!feeder01.ams.xsnews.nl!abp002.ams.xsnews.nl!frontend-F09-10.ams.news.kpn.nl
From	Cecil Westerhof <Cecil@decebal.nl>
Newsgroups	comp.lang.python
Subject	Re: Lucky numbers in Python
Organization	Decebal Computing
References	<87lhhabxod.fsf@Equus.decebal.nl> <mailman.95.1430337506.3680.python-list@python.org> <87d22mbod7.fsf@Equus.decebal.nl> <mailman.103.1430347166.3680.python-list@python.org>
X-Face	"(y8cC@tg_12{">GF'UXTW]FHI2wMiZNrnf'1EFQ&O#$m:f#O7+7}kR<J%a^F2lh4[N~Yz4 nSp#c+aQo1b5=?HcNEkQ7QzF<])O3X4MDL/AYjys&*mt>,v+Pti8=Vi/Z"g^?b"E
X-Homepage	http://www.decebal.nl/
Date	Thu, 30 Apr 2015 02:01:02 +0200
Message-ID	<871tj2bi2p.fsf@Equus.decebal.nl> (permalink)
User-Agent	Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux)
Cancel-Lock	sha1:gjBV3bYux2rhwehIGnnC+ilhJMA=
MIME-Version	1.0
Content-Type	text/plain
Lines	33
NNTP-Posting-Host	81.207.62.244
X-Trace	1430352889 news.kpn.nl 19877 81.207.62.244@kpn/81.207.62.244:46745
Xref	csiph.com comp.lang.python:89590

Show key headers only | View raw

Op Thursday 30 Apr 2015 00:38 CEST schreef Ian Kelly:

> On Wed, Apr 29, 2015 at 3:45 PM, Cecil Westerhof <Cecil@decebal.nl> wrote:
>> Op Wednesday 29 Apr 2015 21:57 CEST schreef Ian Kelly:
>>> 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).
>>
>> What do you mean by this? Executing:
>> lucky_numbers(5)
>> gives:
>> [1, 3]
>>
>> So the last element (5) is deleted.
>
> Off by one error on my part. This is why negative skip values on
> ranges and slices are not recommended: they're confusing. :-)
>
> In that case you can definitely omit the middle term of the slice,
> which will be both more concise and clearer in intent, though
> probably not significantly faster.

It is certainly nit faster. It is even significantly slower. With the
middle term lucky_numbers(int(1e6)) takes 0.13 seconds. Without it
takes 14.3 seconds. Hundred times as long.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof

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

csiph-web