How to Create a Matrix in Python?

A matrix in python is a two-dimensional list. The matrix is made of rows and columns. We can add n number of rows and columns in the matrix. Matrix will be any type of number like integer, float, complex numbers. Also, we can make operations on the matrix. We can add, subtract, multiply and divide two matrices. Moreover, there are many operations we can perform on the matrix. Let’s understand this with examples.

How to create a matrix in python?

There are two ways to implement a matrix in python. 

1. Using a list to implement matrix.

In this, we create and operate the matrix manually. We need to declare functions for performing various operations on it.

Example

r = int(input("Enter number of rows:"))
c = int(input("Enter number of columns:"))

matrix = []

for i in range(r):
   row = []
   for j in range(c):
       row.append(int(input("Enter element of [{}][{}]:".format(i,j))))
   matrix.append(row)

print("Entered matrix is")

for i in range (r):
   for j in range(c):
       print(matrix[i][j], end=" ")
   print("")

Output

Enter number of rows:3
Enter number of columns:3
Enter element of [0][0]:1
Enter element of [0][1]:2
Enter element of [0][2]:3
Enter element of [1][0]:4
Enter element of [1][1]:5
Enter element of [1][2]:6
Enter element of [2][0]:7
Enter element of [2][1]:8
Enter element of [2][2]:9
Entered matrix is
1 2 3 
4 5 6 
7 8 9

2. Using NumPy library to implement matrix.

NumPy is a library in python. It is used to manage multidimensional arrays and matrices. To perform operations on it, NumPy provides a wide scale of inbuilt functions which will give appropriate output.

Example

import numpy as np

r = int(input("Enter number of rows:"))
c = int(input("Enter number of columns:"))

print("Enter data in single line separated by spaces")

data = list(map(int, input().split()))

matrix = np.array(data).reshape(r,c)

print(matrix)

Output

Enter number of rows:3
Enter number of columns:3
Enter data in single line separated by spaces
1 2 3 4 5 6 7 8 9
[[1 2 3]
 [4 5 6]
 [7 8 9]]

Operations on matrix in python examples

We can perform many operations on a matrix in python. In this, we will perform add, subtract, multiply and divide operations into two matrices. Also, we will see how to perform transpose operations on the matrix. Let’s understand with an example.

1. Using list, create two matrices, perform addition and subtract operation.

Use NumPy library to use inbuilt functions. Create two matrices use add() and subtract() to add and subtract matrices.

Example

import numpy as np

m1 = [[1,2],[3,4]]
m2 = [[5,6],[7,8]]

m1 = np.array(m1).reshape(2,2)
m2 = np.array(m2).reshape(2,2)

print("1st matrix is :\n",m1)
print("2nd matrix is :\n",m2)

'''add = m1 + m2'''   #This is the simplest way to add two matrices
add = np.add(m1,m2) # Addition of two matrices using add function.
print("Addition of two matrices is :")
print(add)

'''sub = m1 - m2''' #Simplest way to subtract two matrices
sub = np.subtract(m1,m2) # Subtraction of two matrices using subtract function.
print("Subtraction of two matrices is :")
print(sub)

Output

1st matrix is :
 [[1 2]
 [3 4]]
2nd matrix is :
 [[5 6]
 [7 8]]
Addition of two matrices is :
[[ 6  8]
 [10 12]]
Subtraction of two matrices is :
[[-4 -4]
 [-4 -4]]

2. Perform matrix multiplication and division in python.

Matrix multiplication in python using user input is very simple. Accept two matrices from the user and use dot() to perform multiplication of two matrices. The same goes with the division. There are many functions to divide two matrices. We used a divide function to divide them.

Example

import numpy as np

print("Enter values for 1st matrix")
r = int(input("Enter number of rows:"))
c = int(input("Enter number of columns:"))
print("Enter data in single line separated by spaces")
data = list(map(int, input().split()))
m1 = np.array(data).reshape(r,c)

print("Enter values for 2nd matrix")
r = int(input("Enter number of rows:"))
c = int(input("Enter number of columns:"))
print("Enter data in single line separated by spaces")
data = list(map(int, input().split()))
m2 = np.array(data).reshape(r,c)

print("1st matrix is :\n",m1)
print("2nd matrix is :\n",m2)

mul = m1.dot(m2) #Multiplication of two matrices using dot function
print("Multiplication of two matrices is :")
print(mul)

div = np.divide(m1,m2) #division using divide function
print("Division of two matrices is :")
print(div)

Output

Enter values for 1st matrix
Enter number of rows:3
Enter number of columns:3
Enter data in single line separated by spaces
9 3 1 6 7 3 5 7 2
Enter values for 2nd matrix
Enter number of rows:3
Enter number of columns:3
Enter data in single line separated by spaces
6 1 4 6 8 9 3 2 5
1st matrix is :
 [[9 3 1]
 [6 7 3]
 [5 7 2]]
2nd matrix is :
 [[6 1 4]
 [6 8 9]
 [3 2 5]]
Multiplication of two matrices is :
[[ 75  35  68]
 [ 87  68 102]
 [ 78  65  93]]
Division of two matrices is :
[[1.5        3.         0.25      ]
 [1.         0.875      0.33333333]
 [1.66666667 3.5        0.4       ]]

Transpose of a matrix in python

Transpose of the matrix means changing the positions of row and column. The row becomes a column, and the column becomes a row.

Example

import numpy as np

print("Enter values for 1st matrix")
r = int(input("Enter number of rows:"))
c = int(input("Enter number of columns:"))
print("Enter data in single line separated by spaces")
data = list(map(int, input().split()))
m1 = np.array(data).reshape(r,c)

print("1st matrix is :\n",m1)

trans = m1.transpose()
print("Transpose of given matrix is :")
print(trans)

Output

Enter values for 1st matrix
Enter number of rows:3
Enter number of columns:3
Enter data in single line separated by spaces
1 2 3 4 5 6 7 8 9
1st matrix is :
 [[1 2 3]
 [4 5 6]
 [7 8 9]]
Transpose of given matrix is :
[[1 4 7]
 [2 5 8]
 [3 6 9]]

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