[Numpy-discussion] retrieving original array locations from 2d argsort
Moroney, Catherine M (398D)
Catherine.M.Moroney at jpl.nasa.gov
Mon Jul 15 21:03:26 EDT 2013
I know that there's an easy way to solve this problem, but I'm not sufficiently knowledgeable
about numpy indexing to figure it out.
Here is the problem:
Take a 2-d array a, of any size.
Sort it in ascending order using, I presume, argsort.
Step through the sorted array in order, and for each element in the sorted array,
retrieve what the corresponding (line, sample) indices in the original array are.
For instance:
a = numpy.arange(0, 16).reshape(4,4)
a[0,:] = -1*numpy.arange(0,4)
a[2,:] = -1*numpy.arange(4,8)
asort = numpy.sort(a, axis=None)
for idx in xrange(0, asort.size):
element = asort[idx]
!! Find the line and sample location in a that corresponds to the i-th element in assort
Thank-you for your help,
Catherine
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