ValueError: The truth value of an array with more than one element is ambiguous. Use a.any() or a.all()

This error typically occurs in Python when you’re trying to evaluate the truth value of a NumPy array with more than one element in a boolean context, like an if statement or a while loop. Here’s what each option means:

• a.any(): This returns True if any of the elements of the array a is True.
• a.all(): This returns True if all the elements of the array a are True.

To fix the error, you need to specify whether you want any or all elements to be evaluated as True. Here’s an example:

import numpy as np

a = np.array([True, False, True])
if a.any():
    print("At least one element is True.")
else:
    print("No element is True.")

or

import numpy as np

a = np.array([True, False, True])
if a.all():
    print("All elements are True.")
else:
    print("Not all elements are True.")