NumPy: Create an array which looks like below array

Last update on March 24 2025 13:39:40 (UTC/GMT +8 hours)

Create Zero/One Array Template

Write a NumPy program to create an array like the one below.

Sample Solution:

Python Code:

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

# Generating a lower-triangular matrix of size 4x3 with ones on and below the main diagonal shifted by -1
x = np.tri(4, 3, -1)

# Printing the generated matrix
print(x) 

Sample Output:

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

Explanation:

The above code demonstrates how to create a NumPy array using the np.tri() function.

x = np.tri(4, 3, -1): The current line creates a NumPy array x using the np.tri() function. The function takes three arguments: the number of rows (4), the number of columns (3), and the diagonal below which the elements should be set to 1 (-1). The array is created with ones at and below the specified diagonal and zeros elsewhere.

For more Practice: Solve these Related Problems:

• Create a 2D array template with the top half filled with zeros and the bottom half with ones.
• Write a function that generates an array with alternating rows of zeros and ones based on a given number of rows.
• Validate the pattern by checking that every even-indexed row contains only zeros and odd-indexed rows only ones.
• Extend the template to allow for custom binary patterns and verify the output with assertions.

Python-Numpy Code Editor: