Index multidimensional array with index array

Question

I have an array of index tuples and I would like to use it to pick out values from a multidimensional numpy array,

import numpy
a = numpy.random.rand(10, 10, 10)
idx = [[1, 1, 2], [0, 3, 7], [9, 8, 4], [9, 9, 9]]

The comprehension [a[i, j, k] for i, j, k in idx] only worked if a.ndim was known.

Any hints?

Divakar · Accepted Answer · 2017-02-27 10:24:08Z

8

You could convert the transposed version of idx to a tuple and then index for a vectorized solution -

a[tuple(np.transpose(idx))]

answered Feb 27, 2017 at 10:24

Divakar

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