NumPy: Replace the negative values in a NumPy array with 0

Last update on August 29 2025 12:49:09 (UTC/GMT +8 hours)

Replace Negative Values with 0

Write a NumPy program to replace the negative values in a NumPy array with 0.

Pictorial Presentation:

Python NumPy: Replace the negative values in a NumPy array with 0

Sample Solution:

Python Code:

# Importing the NumPy library and aliasing it as 'np'
import numpy as np

# Creating a NumPy array 'x' containing integers
x = np.array([-1, -4, 0, 2, 3, 4, 5, -6])

# Printing a message indicating the original array will be displayed
print("Original array:")

# Printing the original array 'x' with its elements
print(x)

# Printing a message indicating the replacement of negative values in the array with 0
print("Replace the negative values of the said array with 0:")

# Replacing all negative values in the array 'x' with 0 using boolean indexing
x[x < 0] = 0

# Printing the modified array 'x' after replacing negative values with 0
print(x)

Sample Output:

Original array:                                                        
[-1 -4  0  2  3  4  5 -6]                                              
Replace the negative values of the said array with 0:                  
[0 0 0 2 3 4 5 0]

Explanation:

In the above code –

x = np.array(...) – This part creates a NumPy array 'x' with the given elements.

x[x < 0] = 0: Use boolean indexing to identify and replace all negative elements in the array 'x' with zeros. The expression x < 0 creates a boolean array with the same shape as 'x', where each element is True if the corresponding element in 'x' is negative and False otherwise. The assignment x[x < 0] = 0 replaces all elements of 'x' for which the corresponding boolean value is True with zeros.

print(x): Print the modified array 'x'.

For more Practice: Solve these Related Problems:

Write a NumPy program to replace negative values in an array with 0 using boolean indexing.
Create a function that scans an array for negative values and updates them to 0 without using loops.
Test the replacement by verifying that the sum of negative values becomes 0 after the operation.
Compare the use of np.where and direct indexing approaches to replace negative values and analyze performance.

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