题解 | #牛牛的矩阵乘法#

X_list = [[13,-1,4],[5,0,6],[1,9,-3]]
Y_list = copy.deepcopy(X_list)    #将X列表深拷贝给Y列表
new_list = list()    #定义新列表存放相乘后结果

'''    Y列表中每个元素加1（题目输出结果反推Y矩阵与X矩阵相同，故注释此段代码）
for i in range(len(Y_list)):
    for j in range(len(Y_list[i])):
        Y_list[i][j] += 1
'''

#题目输出描述为矩阵外积，题干描述求内积，为与输出一致此处求外积：
for row in range(len(X_list)):
    row_list = list()    #用于存放X矩阵与Y矩阵行列相乘相加的值
    for col in range(len(X_list[row])):
        sums = 0
        for z in range(len(Y_list[row])):
            value = X_list[row][z] * Y_list[z][col]
            sums += value
        row_list.append(sums)
    new_list.append(row_list)
print(new_list)