[Numpy-discussion] Array search considering order

Andrei Rozanski andrei at ruivo.org
Fri Dec 20 06:41:04 EST 2013


On Fri, Dec 20, 2013 at 11:19:49AM +0000, Oscar Benjamin wrote:
> Date: Fri, 20 Dec 2013 11:19:49 +0000
> From: Oscar Benjamin <oscar.j.benjamin at gmail.com>
> To: Discussion of Numerical Python <numpy-discussion at scipy.org>
> Subject: Re: [Numpy-discussion] Array search considering order
> 
> On 19 December 2013 16:49, Andrei Rozanski <andrei at ruivo.org> wrote:
> >
> > Sorry if I was not clear enough.
> > The SO question is alike what I want. However, in my problem, Im not sure if there will be only one occurence.
> > What I do expect is:
> > Given one array (big one), to retrieve indexes for "query array" occurences.
> > Something like that:
> >
> > array1(big one) - 1,2,3,4,5,6,7,1,2,3,4,5,7,8,9,1,2,3,4,5,6,7,8
> > array2(query) - 1,2,3
> > array3(another query) - 8,7,6
> >
> > result (array1 versus array2) - 0,7,15 (position for match)
> > result (array1 versus array3) - no matches
> 
> If you look more closely at the SO question you'll see that it does
> answer your problem. The top-rated answer shows how to get an boolean
> array indicating where the matches are. In your case that would be
> 
> [True, False, False, False, False, False, False, True, False, False,
> False, False, False, False, False, True, False, False, False, False,
> False]
> 
> Now just use the numpy.where function to get the indices of the True
> value from this array.
> 
> 
> Oscar
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Hi Oscar,

Thank you for the help.
Indeed. My lack of knowledge on numpy functions didnt aloud my to get that.

That works for me.

best regards.






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