How to invert the elements of a boolean array in Python?

Boolean array inversion is a common operation when working with data that contains True/False values. Python offers several approaches to invert boolean arrays using NumPy functions like np.invert(), the bitwise operator ~, or np.logical_not().

Using NumPy's invert() Function

The np.invert() function performs bitwise NOT operation on boolean arrays ?

import numpy as np

# Create a boolean array
covid_negative = np.array([True, False, True, False, True])
print("Original array:", covid_negative)

# Invert using np.invert()
covid_positive = np.invert(covid_negative)
print("Inverted array:", covid_positive)

Original array: [ True False  True False  True]
Inverted array: [False  True False  True False]

Using the Bitwise NOT Operator (~)

The tilde operator ~ provides a concise way to invert boolean arrays ?

import numpy as np

# Create a boolean array
status = np.array([True, False, True, False])
print("Original:", status)

# Invert using ~ operator
inverted_status = ~status
print("Inverted:", inverted_status)

Original: [ True False  True False]
Inverted: [False  True False  True]

Using NumPy's logical_not() Function

The np.logical_not() function is specifically designed for logical operations ?

import numpy as np

# Create a boolean array
test_results = np.array([True, True, False, True, False])
print("Test results:", test_results)

# Invert using logical_not()
failed_tests = np.logical_not(test_results)
print("Failed tests:", failed_tests)

Test results: [ True  True False  True False]
Failed tests: [False False  True False  True]

Without Using NumPy

You can invert boolean values using Python's built-in not operator with list comprehension ?

# Using regular Python list
original = [True, False, True, False, True]
print("Original list:", original)

# Invert using list comprehension
inverted = [not x for x in original]
print("Inverted list:", inverted)

# Using map function with lambda
inverted_map = list(map(lambda x: not x, original))
print("Using map:", inverted_map)

Original list: [True, False, True, False, True]
Inverted list: [False, True, False, True, False]
Using map: [False, True, False, True, False]

Comparison

Conclusion

For NumPy arrays, use np.invert(), ~, or np.logical_not() for efficient boolean inversion. For regular Python lists without NumPy, use list comprehension with the not operator.