efficiently finding the interval with non-zeros in scipy/numpy in Python?

Posted by user248237 on Stack Overflow See other posts from Stack Overflow or by user248237
Published on 2010-04-12T01:25:29Z Indexed on 2010/04/12 1:33 UTC
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python

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scipy

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numpy

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arrays

suppose I have a python list or a python 1-d array (represented in numpy). assume that there is a contiguous stretch of elements how can I find the start and end coordinates (i.e. indices) of the stretch of non-zeros in this list or array? for example,

a = [0, 0, 0, 0, 1, 2, 3, 4]

nonzero_coords(a) should return [4, 7]. for:

b = [1, 2, 3, 4, 0, 0]

nonzero_coords(b) should return [0, 2].

thanks.

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