Python's axis judgment

axis = 0, operate on the horizontal axis (0th dimension), the direction of operation is vertical operation. Find the sum, maximum, minimum, etc.

axis = 1, process operation on the vertical axis (1st dimension), the direction of operation is horizontal operation. Find the sum, maximum, minimum, etc.

import numpy as np
import numpy as np

data = np.array([[1,1,1,1],
                 [2,2,2,2],
                 [3,3,3,3],
                 [4,4,4,4]])

Out[1]:
array([[1, 1, 1, 1],
       [2, 2, 2, 2],
       [3, 3, 3, 3],
       [4, 4, 4, 4]])


#对横轴进行操作，即纵向运算
np.sum(data,axis=0)
Out[2]:
array([10, 10, 10, 10])

#对纵轴进行操作，即横向运算
np.sum(data,axis=1)
Out[3]:
array([ 4,  8, 12, 16])

references:

https://blog.csdn.net/brucewong0516/article/details/79030994

https://www.cnblogs.com/rrttp/p/8028421.html