python笔记之mean()函数实现求取均值的功能代码

>>> import numpy as np
 
>>> num1 = np.array([[1,2,3],[2,3,4],[3,4,5],[4,5,6]])
>>> now2 = np.mat(num1)
>>> now2
matrix([[1, 2, 3],
    [2, 3, 4],
    [3, 4, 5],
    [4, 5, 6]])
 
 
>>> np.mean(now2) # 对所有元素求均值
3.5
 
 
>>> np.mean(now2,0) # 压缩行，对各列求均值
matrix([[ 2.5, 3.5, 4.5]])
 
 
>>> np.mean(now2,1) # 压缩列，对各行求均值
matrix([[ 2.],
    [ 3.],
    [ 4.],
    [ 5.]])