Multiplying two matrices using Python

By Harsh

In this tutorial, we will be solving multiplication of two matrices in the Python.

Matrix Multiplication of two Matrices in Python

In Python, we will implement a matrix as a nested list.

We can treat each element as a row of the matrix.

For example X=[[1,2], [3,4], [5,7]] would represent a 3×2 matrix. The first row can be selected as X[0] and the element in the first row, the first column can be selected as x[0][0].

Multiplication of two matrices X and Y is defined only if the number of columns in X is equal to the number of rows Y.or else it will lead to an error in the output result.

If X is a (n X m) matrix and Y is a (m x 1) matrix then, XY is defined and has the dimension (n x 1).

You can also read:

• How to Perform Matrix Multiplication of given dimension in Python
• How to create matrix of random numbers in Python – NumPy

Program to multiply two matrices in Python

follow the given below code to implement matrics operation between two matrices.

# 3x3 matrix
X = [[1,3,2],
    [3 ,6,8],
    [5 ,2,1]]
# 3x3 matrix
Y = [[6,8,6],
    [6,3,3],
    [2,5,1]]
# result is 3x4
result = [[0,0,0],
         [0,0,0],
         [0,0,0]]

# iterate through rows of X
for i in range(len(X)):
   # iterate through columns of Y
   for j in range(len(Y[0])):
       # iterate through rows of Y
       for k in range(len(Y)):
           result[i][j] += X[i][k] * Y[k][j]

for r in result:
   print(r)

hence this will result in the following output

[28, 27, 17]
[70, 82, 44]
[44, 51, 37]

congratulation, you have completed and learn how to multiply two matrices in python

Conclusion

In this tutorial, we have learned the following

• what is python
• multiplication of two matrices
• implementation in python script

Hope you got a fair idea about the multiplication of matrix in addition to this we will be covering multiplication of matric using NumPy.