[Numpy-discussion] Silly array question

Christopher Barker Chris.Barker at noaa.gov
Fri Apr 7 13:28:02 EDT 2006


Webb Sprague wrote:
> In R, if you have an Nx2 array of integers, you can use that to index
> an TxS array, yielding a 1xN result.

this seems to work:

 >>> import numpy as N
 >>> I = N.array([[0,0], [1,1], [2,2], [1,1]])
 >>> I
array([[0, 0],
        [1, 1],
        [2, 2],
        [1, 1]])

 >>> M = N. array( [[1, 2, 3, 4], [5, 6, 7, 8], [9,10,11, 12], [13, 14, 
15, 16]])

 >>> M
array([[ 1,  2,  3,  4],
        [ 5,  6,  7,  8],
        [ 9, 10, 11, 12],
        [13, 14, 15, 16]])

 >>> M[I[:,0], I[:,1]]
array([ 1,  6, 11,  6])

-- 
Christopher Barker, Ph.D.
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Chris.Barker at noaa.gov




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