Numpy矩阵运算——python

使用Numpy模块中的内置方法实现矩阵相乘、逆序、转置和求和处理。

import numpy as np

if __name__ == "__main__":
    # 矩阵相乘
    mat1 = np.mat([ [1, 3] ]) # 一行两列
    mat2 = np.mat([ [2], [4] ]) # 两行一列
    mat3 = mat1 * mat2
    print(mat3)

    # 矩阵求逆
    mat4 = np.mat([ [1, 0, 1], [0, 2, 1], [1, 1, 1] ])
    mat5 = mat4.I
    print(mat5)

    # 矩阵转置
    mat6 = np.mat([ [1, 2, 3], [4, 5, 6], [7, 8, 9] ])
    mat7 = mat6.T
    print(mat7)

    # 矩阵每一列的和
    sum1 = mat6.sum(axis=0)
    print(sum1)
    
    # 矩阵每一行的和
    sum2 = mat6.sum(axis=1)
    print(sum2)
 
    # 矩阵与数组之间的转换
    mat8 = np.mat([ [1, 2, 3] ])
    arr1 = np.array(mat8)
    print(arr1)

    arr2 = [3, 4, 5]
    mat9 = np.mat(arr2)
    print(mat9)

输出结果：

[[14]]
[[-1. -1.  2.]
 [-1.  0.  1.]
 [ 2.  1. -2.]]
[[1 4 7]
 [2 5 8]
 [3 6 9]]
[[12 15 18]]
[[ 6]
 [15]
 [24]]
[[1 2 3]]
[[3 4 5]]