np.mean()函數

 1. 數組的操作：

import numpy as np
a = np.array([[1, 2], [3, 4]])
print(a)
print(type(a))
print(np.mean(a))
print(np.mean(a, axis=0)) # axis=0，計算每一列的均值
print(np.mean(a, axis=1)) # 計算每一行的均值

2.矩陣的操作

import numpy as np
num1 = np.array([[1,2,3],[2,3,4],[3,4,5],[4,5,6]])

num2 = np.mat(num1)
print(num2)
print(type(num2))
print(np.mean(num2)) # 對所有元素求均值
print(np.mean(num2,0)) # 壓縮行，對各列求均值
print(np.mean(num2,1)) # 壓縮列，對各行求均值