Subsetting a 2D numpy array

Question

I have looked into documentations and also other questions here, but it seems I have not got the hang of subsetting in numpy arrays yet.

I have a numpy array, and

Answer 1

Another quick way to build the desired index is to use the np.ix_ function:

>>> a[np.ix_(n1, n2)]
array([[ 0,  1,  2,  3,  4],
       [10, 11, 12, 13, 14],
       [20, 21, 22, 23, 24],
       [30, 31, 32, 33, 34],
       [40, 41, 42, 43, 44]])

This provides a convenient way to construct an open mesh from sequences of indices.