append value to numpy array

1x = np.random.randint(2, size=10)
2x = np.append(x, 2)

1A= [[1, 2, 3], [4, 5, 6]]
2np.append(A, [[7, 8, 9]], axis=0)
3
4    >> array([[1, 2, 3],
5              [4, 5, 6],
6              [7, 8, 9]])
7#or 
8np.r_[A,[[7,8,9]]]

1>>> import numpy as np
2>>> np.append([[0, 1, 2], [3, 4, 5]],[[6, 7, 8]], axis=0)
3array([[0, 1, 2],
4       [3, 4, 5],
5       [6, 7, 8]])

1>>> np.append([[1, 2, 3], [4, 5, 6]], [[7, 8, 9]], axis=0)
2array([[1, 2, 3],
3       [4, 5, 6],
4       [7, 8, 9]])
5>>> np.append([[1, 2, 3], [4, 5, 6]], [7, 8, 9], axis=0)
6Traceback (most recent call last):
7    ...
8ValueError: all the input arrays must have same number of dimensions, but
9the array at index 0 has 2 dimension(s) and the array at index 1 has 1
10dimension(s)
11

1x1 = [1, 2]
2x2 = [1, 2]
3print(np.add(x1, x2))
4# [2, 4]