How to Randomly Remove Elements from a NumPy Array?

This tutorial will discuss about unique ways to randomly remove elements from a numpy array.

Suppose we have an array of numbers,

numbers = np.array([34, 35, 78, 61, 56, 71, 90, 91])

For this, we will create an array of random indices from this array of size N. Like this,

# Use the `random.choice()` function to
# randomly select the indices of the elements to remove
indicesToRemove = np.random.choice(
                            numbers.size,
                            num,
                            replace=False)

Then we will pass this array of random index positions into the numpy.delete() function, along with the numpy array. Like this,

# Update NumPy Array without the specified elements
numbers = np.delete(numbers, indicesToRemove)

It will delete all the elements at the given index positions. This way we can delete the random values from a number array.

In the belowe example, we will delete 2 random values from a NumPy Array.

Let’s see the complete example,

import numpy as np

# Create a NumPy Array
numbers = np.array([34, 35, 78, 61, 56, 71, 90, 91])

# Define the number of
# elements to remove
num = 2

# Use the `random.choice` function to
# randomly select the indices of the elements to remove
indicesToRemove = np.random.choice(
                            numbers.size,
                            num,
                            replace=False)

# Update NumPy Array without the specified elements
numbers = np.delete(numbers, indicesToRemove)

# Print the numpy array
print(numbers)

Output

[35 78 61 56 71 90]

Summary

We learned how to delete N random values from a NumPy Array in Python.