Python NOT Operator

Python NOT

To perform logical NOT operation in Python, you can use the not keyword prior to the boolean value or boolean operand.

Syntax of not keyword

The syntax to use not operator is:

not operand

not operator takes only one operand. It returns True if the operand is False and returns False if the operand is True.

Truth Table - NOT Operator

Following is the truth table of not operator with boolean values.

OperandReturn Value
TrueFalse
FalseTrue

Examples

1. Python NOT with boolean values

In the following example, we will use the not keyword to perform logical not operation on True and False boolean values.

Python Program

#not True
a = True
c = not a
print('not',a,'is:',c)

#not False
a = False
c = not a
print('not',a,'is:',c)

Explanation of the Code:

  1. First Case (not True): The result is False because True becomes False when the not operator is applied.
  2. Second Case (not False): The result is True because False becomes True when the not operator is applied.

Output

not True is: False
not False is: True

2. NOT Operator with non-boolean operands

You can use non-zero values instead of True and zero for False. The not operator converts non-zero values into False and zero into True.

Python Program

#not 5

a = 5
c = not a
print('not',a,'is:',c)

#not 0
a = 0
c = not a
print('not',a,'is:',c)

Explanation of the Code:

  1. First Case (not 5): The result is False because the operand is a non-zero integer, which is considered True, so not returns False.
  2. Second Case (not 0): The result is True because the operand is 0, which is considered False, so not returns True.

Output

not 5 is: False
not 0 is: True

Summary

In this tutorial, we learned how to use the Python not logical operator with boolean and non-boolean operands. The not operator inverts the truth value of its operand, returning True for False operands and False for True operands.

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