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Re: looping in array vs looping in a dic

References <007b2d71-3355-4085-b84f-204834b2c8d0@googlegroups.com> <505B6A00.10308@mrabarnett.plus.com> <CALwzid=HowMzWmgiU2+2Gu4opxWu0Hx-iOFRZZcXi=BAdKVfrw@mail.gmail.com>
From Ian Kelly <ian.g.kelly@gmail.com>
Date 2012-09-20 13:29 -0600
Subject Re: looping in array vs looping in a dic
Newsgroups comp.lang.python
Message-ID <mailman.971.1348169395.27098.python-list@python.org> (permalink)

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On Thu, Sep 20, 2012 at 1:28 PM, Ian Kelly <ian.g.kelly@gmail.com> wrote:
> Expanding on what MRAB wrote, since you probably have far fewer
> categories than pixels, you may be able to take better advantage of
> numpy's vectorized operations (which are pretty much the whole point
> of using numpy in the first place) by looping over the categories
> instead:
>
> for cat in categories:
>     totals[cat] += np.sum(valuesCategory * (valuesRaster == cat))

Of course, that should have read:

for cat in categories:
    totals[cat] += np.sum(valuesRaster * (valuesCategory == cat))

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looping in array vs looping in a dic giuseppe.amatulli@gmail.com - 2012-09-20 11:31 -0700
  Re: looping in array vs looping in a dic MRAB <python@mrabarnett.plus.com> - 2012-09-20 20:09 +0100
  Re: looping in array vs looping in a dic Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-20 13:28 -0600
  Re: looping in array vs looping in a dic Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-20 13:29 -0600
    Re: looping in array vs looping in a dic giuseppe.amatulli@gmail.com - 2012-09-20 16:35 -0700
      Re: looping in array vs looping in a dic MRAB <python@mrabarnett.plus.com> - 2012-09-21 00:58 +0100
    Re: looping in array vs looping in a dic giuseppe.amatulli@gmail.com - 2012-09-20 16:35 -0700

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