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From: Ian Kelly <ian.g.kelly@gmail.com>
Date: Wed, 29 Apr 2015 20:55:29 -0600
Subject: Re: Lucky numbers in Python
To: Python <python-list@python.org>
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On Wed, Apr 29, 2015 at 6:01 PM, Cecil Westerhof <Cecil@decebal.nl> wrote:
> Op Thursday 30 Apr 2015 00:38 CEST schreef Ian Kelly:
>> 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.

That would be rather surprising, since it's the same operation being
performed, so I did my own timing and came up with 0.25 seconds (best
of 3) with the middle term and 0.22 seconds without.

I suspect that you tested it as "del sieve[skip_count - 1 :
skip_count]" (which would delete only one item) rather than "del
sieve[skip_count - 1 :: skip_count]".