import numpy as np

a = np.array([i for i in range(5)])
b = np.array([i for i in range(5, 10)])
print('a:', a)
print('b:', b)
c = np.stack([a,b], axis=0)
print(c)
d = np.stack([a,b], axis=1)
print(d)
e = np.stack([a,b], axis=-1)
print(e)

结果：
a:   [0 1 2 3 4]

b:   [5 6 7 8 9]

c:   [[0 1 2 3 4]     # axis=0
       [5 6 7 8 9]]

d:   [[0 5]     # axis=1
       [1 6]
       [3 8]
       [4 9]]

e:   [[0 5]     # axis=-1
       [1 6]
       [3 8]
       [4 9]]