NumPy: Get the number of nonzero elements in an array

Last update on August 29 2025 12:50:17 (UTC/GMT +8 hours)

Count Non-Zero Elements in Array

Write a NumPy program to get the number of non-zero elements in an array.

Pictorial Presentation:

Sample Solution:

Python Code:

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

# Creating a 2x3 NumPy array 'x' containing specific values
x = np.array([[0, 10, 20], [20, 30, 40]])

# Displaying the original 2x3 array 'x'
print("Original array:")
print(x)

# Counting the number of non-zero elements in the array 'x' using np.count_nonzero
print("Number of non-zero elements in the above array:")
print(np.count_nonzero(x))

Sample Output:

Original array:                                                        
[[ 0 10 20]                                                            
 [20 30 40]]                                                           
Number of non zero elements in the above array:                        
5 

Explanation:

In the above code –

‘x = np.array([[0, 10, 20], [20, 30, 40]])’ creates a 2D array x with the given elements.

print(np.count_nonzero(x)): The np.count_nonzero() function is used to count the number of non-zero elements in the array ‘x’. In this case, there are 5 non-zero elements in the array.

For more Practice: Solve these Related Problems:

• Write a NumPy program to count the non-zero elements in a 2D array using np.count_nonzero.
• Create a function that returns the indices and count of non-zero elements in an array.
• Test the non-zero element count on arrays before and after modifying specific values to zero.
• Use boolean indexing to filter out non-zero values and sum the count for validation.

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• NumPy Array Exercises Home ↩
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