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Re: list comprehension return a list and sum over in loop

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From Christian Gollwitzer <auriocus@gmx.de>
Newsgroups comp.lang.python
Subject Re: list comprehension return a list and sum over in loop
Date Fri, 12 Dec 2014 10:09:17 +0100
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Am 12.12.14 09:30, schrieb KK Sasa:
> Mark Lawrence於 2014年12月12日星期五UTC+8下午3時17分43秒寫道：
> Hi Mark and Yotam, Thanks for kind reply. I think I didn't make my
> problem clear enough. The slow part is "[d2(t[k]) for k in
> xrange(1000)]". In addition, I don't need to construct a list of 1000
> lists inside, but my aim is to get the sum of all "d2(t[k])". I
> wonder if there is any method to sum up efficiently.

Not sure I understand what you need, but it seems that NumPy would be a 
more efficient method. numpy.sum can sum elements along every dimensions 
of a higher-dimensional matrix, and in general NumPy stores the elements 
in native doubles instead of Python lists, which improves both 
performance and memory usage
	
	Christian

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Thread

list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-11 22:22 -0800
  Re: list comprehension return a list and sum over in loop Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-12 07:17 +0000
    Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 00:30 -0800
      Re: list comprehension return a list and sum over in loop Christian Gollwitzer <auriocus@gmx.de> - 2014-12-12 10:09 +0100
      Re: list comprehension return a list and sum over in loop Peter Otten <__peter__@web.de> - 2014-12-12 10:13 +0100
        Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 01:45 -0800
          Re: list comprehension return a list and sum over in loop Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-12-12 13:12 +0200
            Re: list comprehension return a list and sum over in loop Peter Otten <__peter__@web.de> - 2014-12-12 13:32 +0100
              Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 05:09 -0800
                Re: list comprehension return a list and sum over in loop Peter Otten <__peter__@web.de> - 2014-12-12 17:08 +0100
                Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 19:04 -0800
                Re: list comprehension return a list and sum over in loop Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-12-13 11:27 +0000
            Re: list comprehension return a list and sum over in loop KK Sasa <genwei007@gmail.com> - 2014-12-12 05:03 -0800
  Re: list comprehension return a list and sum over in loop Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-12-12 20:46 +1100
  Re: list comprehension return a list and sum over in loop Oscar Benjamin <oscar.j.benjamin@gmail.com> - 2014-12-12 16:47 +0000
  Re: list comprehension return a list and sum over in loop pecore@pascolo.net - 2014-12-13 13:38 +0100

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