On Thu, Dec 19, 2013 at 01:51:30PM +0000, Oscar Benjamin wrote:

Date: Thu, 19 Dec 2013 13:51:30 +0000 From: Oscar Benjamin oscar.j.benjamin@gmail.com To: Discussion of Numerical Python numpy-discussion@scipy.org Subject: Re: [Numpy-discussion] Array search considering order

On 19 December 2013 12:51, rootspin andrei@ruivo.org wrote:

...

Hello,

Need some help in searching arrays (Im new to numpy) Is it possible to search a array, using another array considering order/sequence?

x = np.array([1,2,3,4,5,6], np.int32)

y = np.array([1,4,3,2,6,5], np.int32)

query= np.array([1,2,3],np.int32)

x versus query True y versus query False

Tried with:

np.searchsorted(x,query) -------> array([0, 1, 2]) np.searchsorted(y,query) -------> array([0, 1, 4])

I'm not sure if I understand your problem do you mean that you want to find subarrays of an array the same way that e.g. "in" for strings tests for substrings:

...

...

...

'asd' in 'qweasdzxc'

True

If so then perhaps this SO question has the answer you want: http://stackoverflow.com/questions/7100242/python-numpy-first-occurrence-of-...

Oscar _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion

Thank you Oscar for your answer.

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

Thanks for the help.

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@gmail.com To: Discussion of Numerical Python numpy-discussion@scipy.org Subject: Re: [Numpy-discussion] Array search considering order

On 19 December 2013 16:49, Andrei Rozanski andrei@ruivo.org wrote:

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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 _______________________________________________ NumPy-Discussion mailing list NumPy-Discussion@scipy.org http://mail.scipy.org/mailman/listinfo/numpy-discussion

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.