not — Intermediate Playground

Logical NOT operator; inverts a boolean value

Python Playground

# Double negation and bool()
x = 42
print(not not x)     # Same as bool(x)
print(bool(x))       # Clearer way

# not vs !=
items = [1, 2, 3]
# These are different:
print(not items == [])   # not (items == []) = not False = True
print(items != [])        # True (preferred)

# De Morgan's laws
a, b = True, False
print(f"not (a or b) = {not (a or b)}")
print(f"(not a) and (not b) = {(not a) and (not b)}")
print(f"not (a and b) = {not (a and b)}")
print(f"(not a) or (not b) = {(not a) or (not b)}")

Output

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'not' always returns a boolean. Use it for readability, but prefer 'is not', 'not in', and '!=' over 'not ... is', 'not ... in', and 'not ... =='.

Challenge

Try modifying the code above to explore different behaviors. Can you extend the example to handle a new use case?

View all Intermediate examples for not