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Re: bit count or bit set && Python3

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On 2012-10-25, Steven D'Aprano <steve+comp.lang.python@pearwood.info> wrote:
> On Fri, 26 Oct 2012 02:31:53 +1100, Chris Angelico wrote:
>> On Fri, Oct 26, 2012 at 2:25 AM, Christian Heimes
>> <christian@python.org>
>> wrote:
>>> Simple, easy, faster than a Python loop but not very elegant:
>>>
>>>    bin(number).count("1")
>> 
>> Unlikely to be fast.
>
> Oh I don't know about that.

Yes indeed! Python string operations are fast enough and its
arithmetic slow enough that I no longer assume I can beat a neat
lexicographical solution. Try defeating the following with
arithmetic:

def is_palindrom(n):
   s = str(n)
   return s = s[::-1]

> Here's some timing results using Python 2.7:

Excellent work.

You can of course drop to C for arithmetic and likely triumph
over Python strings. That's never been applicable for me, though.

-- 
Neil Cerutti

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Re: bit count or bit set && Python3 Chris Angelico <rosuav@gmail.com> - 2012-10-26 02:31 +1100
  Re: bit count or bit set && Python3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-25 15:57 +0000
    Re: bit count or bit set && Python3 rusi <rustompmody@gmail.com> - 2012-10-25 09:17 -0700
      Re: bit count or bit set && Python3 Chris Angelico <rosuav@gmail.com> - 2012-10-26 03:29 +1100
        Re: bit count or bit set && Python3 rusi <rustompmody@gmail.com> - 2012-10-25 09:37 -0700
      Re: bit count or bit set && Python3 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-10-25 17:44 +0100
      Re: bit count or bit set && Python3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-25 17:16 +0000
    Re: bit count or bit set && Python3 Serhiy Storchaka <storchaka@gmail.com> - 2012-10-25 22:07 +0300
    Re: bit count or bit set && Python3 Neil Cerutti <neilc@norwich.edu> - 2012-10-25 20:00 +0000
      Re: bit count or bit set && Python3 Neil Cerutti <neilc@norwich.edu> - 2012-10-25 20:04 +0000
      Re: bit count or bit set && Python3 Ian Kelly <ian.g.kelly@gmail.com> - 2012-10-25 14:20 -0600
        Re: bit count or bit set && Python3 Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-10-25 23:48 +0000
        Re: bit count or bit set && Python3 Neil Cerutti <neilc@norwich.edu> - 2012-10-26 12:56 +0000
    Re: bit count or bit set && Python3 Charles Hixson <charleshixsn@earthlink.net> - 2012-10-25 09:08 -0700
    Re: bit count or bit set && Python3 Mark Lawrence <breamoreboy@yahoo.co.uk> - 2012-10-25 22:51 +0100

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