count occurrences of arrays in multidimensional arrays in python

Question

I have the following type of arrays:

a = array([[1,1,1],
           [1,1,1],
           [1,1,1],
           [2,2,2],
           [2,2,2],
           [2,2,2],
         


        

Answer 1

Since numpy-1.13.0, np.unique can be used with axis argument:

>>> np.unique(a, axis=0, return_counts=True)

(array([[1, 1, 1],
        [2, 2, 2],
        [3, 3, 0]]), array([3, 3, 3]))