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Groups > comp.lang.python > #101363

Re: SUM only of positive numbers from array

From Peter Otten <__peter__@web.de>
Newsgroups comp.lang.python
Subject Re: SUM only of positive numbers from array
Date 2016-01-08 09:17 +0100
Organization None
Message-ID <mailman.59.1452241084.2305.python-list@python.org> (permalink)
References <50beb098-f854-4b17-b157-1be075d91f4d@googlegroups.com>

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Davorin Bajic wrote:

> Hi All,
> 
> I should help...
> 
> I want to calculate the sum of a positive number, for each row:
> 
> 
> x = ((mat_1 / s_1T)-(s_2 / total))
> y = (np.sum(x > 0, axis=1)).reshape(-1, 1).tolist()
> 
> However, this part of the code only calculation count, I need sum.
> 
> Any ideas how to solve this problem?

Use x>0 as "index":

>>> import numpy
>>> x = numpy.array([1, -2, 3])
>>> x>0
array([ True, False,  True], dtype=bool)
>>> x[x>0]
array([1, 3])
>>> x[x>0].sum()
4

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Thread

SUM only of positive numbers from array Davorin Bajic <davorinbajic@gmail.com> - 2016-01-07 20:12 -0800
  Re: SUM only of positive numbers from array Peter Otten <__peter__@web.de> - 2016-01-08 09:17 +0100
  Re: SUM only of positive numbers from array Davorin Bajic <davorinbajic@gmail.com> - 2016-01-08 04:33 -0800

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