NumPy: Create a 3-D array with ones on the diagonal and zeros elsewhere

Last update on August 29 2025 12:46:34 (UTC/GMT +8 hours)

3D Array with Diagonal Ones

Write a NumPy program to create a 3-D array with ones on a diagonal and zeros elsewhere.

Pictorial Presentation:

Python NumPy: Create a 3-D array with ones on the diagonal and zeros elsewhere

Sample Solution:

Python Code:

# Importing the NumPy library with an alias 'np'
import numpy as np

# Creating a 3x3 identity matrix using the eye method in NumPy
x = np.eye(3)

# Printing the created identity matrix
print(x)

Sample Output:

[[ 1.  0.  0.]                                                         
 [ 0.  1.  0.]                                                         
 [ 0.  0.  1.]]

Explanation:

The above code demonstrates how to create an identity matrix (a square matrix with ones on the diagonal and zeros elsewhere) using the np.eye() function in NumPy.

x = np.eye(3): np.eye(3This line creates a 3x3 identity matrix x using the np.eye() function. The function takes one argument, which is the number of rows (and columns, since it's a square matrix) in the resulting identity matrix.

print(x): This line prints the identity matrix x:

For more Practice: Solve these Related Problems:

Create a 3D array where each 2D sub-array is an identity matrix using np.eye in a loop or comprehension.
Write a function that generates a 3D array with diagonal ones for any given square dimension and depth.
Validate that every 2D slice of the 3D array contains ones on the main diagonal and zeros elsewhere.
Extend the concept to create a 3D array where only a specific cross-section diagonal is set to one.

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