Invert Elements of Boolean Arrays

In this article, we will learn how to invert the elements of a boolean array that contains boolean values like True or False.

What is a Boolean Array in Python?

A boolean array is an array that has boolean values like True or False or maybe 1 or 0. A boolean array can be formed by using dtype = bool. Everything is considered true except for 0, None, False or empty strings.

import numpy as np

arr_bool = np.array([1, 1.1, 0, None, 'a', '', True, False], dtype=bool)
print(arr_bool)

Output:

[ True  True False False  True False  True False]

Methods for inverting elements of Boolean Arrays

Following are the methods you can apply for inverting the elements of a boolean array in Python.

Using the np.invert() function

Using the inbuilt np. invert() function you can invert the elements of a boolean array.

import numpy as np
arr = np.array((True, True, False, True, False))
arr_inver = np.invert(arr)
print(arr_inver)

Output:

[False False  True False  True]

Using the if-else method

In this method, we will check the value of the index of each element in the array. If the value is zero it will be changed to 1 and vice-versa. Also if the value is True it will be changed to False.

arr = ((0, 1, 0, 1))
a1 = list(arr)
  
for x in range(len(a1)):
    if(a1[x]):
        a1[x] = 0
    else:
        a1[x] = 1
  
print(a1)

Output:

[1, 0, 1, 0]

Conclusion

In summary, we learned different ways to invert the elements of a boolean array in python. Numpy is a flexible python library and provides a variety of functions to work with.