Question

我想将两个2D数组相乘，使第一个数组的行与第二个数组的列相乘。

所以我调换了第二个数组，使其列更改为transposedone的行。然后我逐个从2D数组中提取出两行，并将它们视为两个简单列表，将它们相乘并将它们存储在另一个列表中。

我想将它们存储为生成的2D数组的00（行 - 列）元素。我该怎么办？

NO_OF_ROWS_A=int(input("Enter the no. of rows in A: "))
NO_OF_COLUMNS_A=int(input("Enter the no. of columns in A: "))
NO_OF_ROWS_B=int(input("Enter the no. of rows in B : "))
NO_OF_COLUMNS_B=int(input("Enter the no. of columns in B: "))

mat_A=[[] for i in range(NO_OF_ROWS_A)]
for i in range(NO_OF_ROWS_A):
    for j in range (NO_OF_COLUMNS_A):
        print("Enter",i,j,"element for mat A: ")
        a=int(input())
        mat_A[i].append(a)

mat_B=[[] for i in range(NO_OF_ROWS_B)]
for i in range(NO_OF_ROWS_B):
    for j in range (NO_OF_COLUMNS_B):
        print("Enter",i,j,"element for mat B: ")
        b=int(input())
        mat_B[i].append(b)

import itertools
mat_B_trans = list(itertools.zip_longest(*mat_B))#transposes B to change its col into row

sum_list_x=0

mat_C=[[] for i in range(NO_OF_ROWS_A)]
for i in range(NO_OF_ROWS_A):
    for j in range(NO_OF_COLUMNS_B):
        for i in range(NO_OF_ROWS_A):#extracts row of A
            list_row_a=mat_A[i]
        for j in range(NO_OF_COLUMNS_B):#extracts row of trans_B which is col of B
            list_column_b=mat_B_trans[i]
        list_temp_multiple=[a*b for a,b in zip(list_row_a, list_column_b)]#list of multiples of same indices of A & B
        sum_list=sum(list_temp_multiple)#sum of prev list elemets
        sum_list_x=sum_list_x + sum_list

        c = sum_list_x
        mat_C[i].append(c)
print(mat_C)

Answer 1

以下是否适合您：

[sum(a * b for a, b in zip(*combined_row)) for combined_row in zip(mat_A, zip(*mat_B))]

这转换mat_B，每行压缩两个矩阵，然后将每列的行相乘并将相乘的值相加，使一个值列表。

Answer 2

使用NumPy，您的整个程序可以写成：

import numpy as np

mat_A = np.matrix(input('Enter matrix A: '))
mat_B = np.matrix(input('Enter matrix B: '))
mat_C = mat_A * mat_B
print(mat_C)

产量

Enter matrix A: [[1,2], [3,4]]
Enter matrix B: [[5,6], [7,8]]
[[19 22]
 [43 50]]

Answer 3

[[sum(a*b for a,b in zip(mat_A_row,mat_B_col)) for mat_A_col in zip(*mat_B)] for mat_A_row in mat_A]

zip（* X）以元组格式返回矩阵X的转置

如何将两个列表相乘并将其总和存储在2D数组中？

3 个答案: