Python Program to Print an Identity Matrix

An identity matrix is a square matrix where the diagonal elements are 1 and all other elements are 0. In Python, you can create an identity matrix using nested loops or the NumPy library.

Using Nested Loops

The basic approach uses two nested loops to check if the row index equals the column index ?

n = 4
print("The value of n has been initialized to " + str(n))

for i in range(0, n):
    for j in range(0, n):
        if(i == j):
            print("1", sep=" ", end=" ")
        else:
            print("0", sep=" ", end=" ")
    print()

The value of n has been initialized to 4
1 0 0 0 
0 1 0 0 
0 0 1 0 
0 0 0 1 

Using NumPy

NumPy provides a built-in function eye() to create identity matrices ?

import numpy as np

n = 4
identity_matrix = np.eye(n, dtype=int)
print("Identity matrix using NumPy:")
print(identity_matrix)

Identity matrix using NumPy:
[[1 0 0 0]
 [0 1 0 0]
 [0 0 1 0]
 [0 0 0 1]]

How It Works

In the nested loop approach:

• The outer loop iterates through rows (i from 0 to n-1)
• The inner loop iterates through columns (j from 0 to n-1)
• When i equals j (diagonal position), print "1"
• When i does not equal j (off-diagonal position), print "0"
• After each row, print() moves to the next line

Comparison

Conclusion

Use nested loops to understand the concept of identity matrices. For practical applications, NumPy's eye() function is more efficient and returns a proper matrix object.