Python program to multiply two matrices

Given two matrix the task is that we will have to create a program to multiply two matrices in python.

Examples:

Input : X = [[1, 7, 3],
             [3, 5, 6],
             [6, 8, 9]]
       Y = [[1, 1, 1, 2],
           [6, 7, 3, 0],
           [4, 5, 9, 1]]
 
Output : [55, 65, 49, 5]
         [57, 68, 72, 12]
         [90, 107, 111, 21]

Using Simple Nested Loops
In this program we have to use nested for loops to iterate through each row and each column.



filter_none

edit
close

play_arrow

link
brightness_4
code

# Program to multiply two matrices using nested loops
  
# take a 3x3 matrix
A = [[12, 7, 3],
    [4, 5, 6],
    [7, 8, 9]]
  
# take a 3x4 matrix    
B = [[5, 8, 1, 2],
    [6, 7, 3, 0],
    [4, 5, 9, 1]]
      
result = [[0, 0, 0, 0],
        [0, 0, 0, 0],
        [0, 0, 0, 0]]
  
# iterating by row of A
for i in range(len(A)):
  
    # iterating by coloum by B 
    for j in range(len(B[0])):
  
        # iterating by rows of B
        for k in range(len(B)):
            result[i][j] += A[i][k] * B[k][j]
  
for r in result:
    print(r)

chevron_right


Output:

[114, 160, 60, 27]
[74, 97, 73, 14]
[119, 157, 112, 23]

Method 2: Matrix Multiplication Using Nested List. We use zip in Python.

filter_none

edit
close

play_arrow

link
brightness_4
code

# Program to multiply two matrices using list comprehension
  
# take a 3x3 matrix
A = [[12, 7, 3],
    [4, 5, 6],
    [7, 8, 9]]
  
# take a 3x4 matrix
B = [[5, 8, 1, 2],
    [6, 7, 3, 0],
    [4, 5, 9, 1]]
  
# result will be 3x4
result = [[sum(a * b for a, b in zip(A_row, B_col)) 
                        for B_col in zip(*B)]
                                for A_row in A]
  
for r in result:
    print(r)

chevron_right


Output:

[114, 160, 60, 27]
[74, 97, 73, 14]
[119, 157, 112, 23]



My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.




Article Tags :
Practice Tags :


Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.