减去两个不同维度的数组

Question

What does this difference mean?

np.array([[1], [2]]) - np.array([[1, 2]])

It outputs

array([[ 0, -1],
       [ 1,  0]])

Answer 1

Whereas np.array([[1], [2]]) is an array of dimension (2,1) , np.array([[1, 2]]) is an array of dimension (1,2) . According to the rules of broadcasting , the difference is a numpy array of size (2,2) .