Python使用扩展库numpy计算矩阵加权平均值

本文介绍Python扩展库numpy的函数average()的用法。

>>> import numpy as np

# 创建二维矩阵

>>> x = np.matrix([[1,2,3], [4,5,6]])

# 设置权重

>>> w1 = [0.3, 0.7]

# 纵向计算加权平均

>>> np.average(x, axis=0, weights=w1)

matrix([[ 3.1,  4.1,  5.1]])

>>> w2 = [0.3, 0.3, 0.4]

# 横向计算加权平均

>>> np.average(x, axis=1, weights=w2)

matrix([[ 2.1],

        [ 5.1]])

>>> np.average(x, axis=1, weights=w2, returned=True)

(matrix([[ 2.1],

        [ 5.1]]), array([[ 1.],

       [ 1.]]))