Python Logical Operators

Python logical operators are used to combine conditional statements, allowing you to perform operations based on multiple conditions. These Python operators, alongside arithmetic operators, are special symbols used to carry out computations on values and variables. In this article, we will discuss logical operators in Python definition and also look at some Python logical operators programs, to completely grasp the concept.

# Example: Logical Operators (AND, OR, NOT) with generic variables
a, b, c = True, False, True

# AND: Both conditions must be True
if a and c:
    print("Both a and c are True (AND condition).")

# OR: At least one condition must be True
if b or c:
    print("Either b or c is True (OR condition).")

# NOT: Reverses the condition
if not b:
    print("b is False (NOT condition).")

In Python, Logical operators are used on conditional statements (either True or False). They perform Logical AND, Logical OR, and Logical NOT operations.

Truth Table for Logical Operators in Python

Truth Table for Python Logical Operators

AND Operator in Python

The Boolean AND operator returns True if both the operands are True else it returns False.

Logical AND operator Examples

a = 10
b = 10
c = -10
if a > 0 and b > 0:
    print("The numbers are greater than 0")
if a > 0 and b > 0 and c > 0:
    print("The numbers are greater than 0")
else:
    print("Atleast one number is not greater than 0")

Output

The numbers are greater than 0
Atleast one number is not greater than 0

Example 2: The code checks if all variables a, b, and c evaluate to True, printing a message accordingly.

a = 10
b = 12
c = 0
if a and b and c:
    print("All the numbers have boolean value as True")
else:
    print("Atleast one number has boolean value as False")

Output

Atleast one number has boolean value as False

Note: If the first expression is evaluated to be false while using the AND operator, then the further expressions are not evaluated.

Python OR Operator

The Boolean OR operator returns True if either of the operands is True.

Logical OR operator in Python Examples

a = 10
b = -10
c = 0
if a > 0 or b > 0:
    print("Either of the number is greater than 0")
else:
    print("No number is greater than 0")
if b > 0 or c > 0:
    print("Either of the number is greater than 0")
else:
    print("No number is greater than 0")

Output

Either of the number is greater than 0
No number is greater than 0

Example 2: The code checks if any of the variables a, b, or c has a boolean value as True; if so, it prints “At least one number has boolean value as True”, otherwise, it prints “All the numbers have boolean value as False”.

a = 10
b = 12
c = 0
if a or b or c:
    print("Atleast one number has boolean value as True")
else:
    print("All the numbers have boolean value as False")

Output

Atleast one number has boolean value as True

Note: If the first expression is evaluated to be True while using or operator, then the further expressions are not evaluated.

Python NOT Operator

The Boolean NOT operator works with a single boolean value. If the boolean value is True it returns False and vice-versa.

Logical NOT Operator Examples

The code checks if a is divisible by either 3 or 5, otherwise, it prints a message indicating that it is not. Let’s look at this Python NOT operator program to understand its working.

a = 10

if not a:
    print("Boolean value of a is True")
if not (a % 3 == 0 or a % 5 == 0):
    print("10 is not divisible by either 3 or 5")
else:
    print("10 is divisible by either 3 or 5")

Output

10 is divisible by either 3 or 5

Order of Precedence of Logical Operators

In the case of multiple operators, Python always evaluates the expression from left to right. We can verify Python logical operators precedence by the below example. 

def order(x):
    print("Method called for value:", x)
    return True if x > 0 else False


a = order
b = order
c = order
if a(-1) or b(5) or c(10):
    print("Atleast one of the number is positive")

Output

Method called for value: -1
Method called for value: 5
Atleast one of the number is positive

Python Logical Operators – FAQs

How to use and, or, and not operators in Python?

In Python, logical operators are used to combine or invert boolean values:

and: Returns True if both operands are True.

result = (5 > 3) and (8 > 5)  # Returns True

or: Returns True if at least one of the operands is True.

result = (5 > 3) or (8 < 5)  # Returns True

not: Returns True if the operand is False, and False if the operand is True.

result = not (5 > 3)  # Returns False

How do logical operators differ from bitwise operators in Python?

Logical and bitwise operators serve different purposes:

Logical Operators: Work on boolean values and are used for logical operations.

result = True and False  # Logical AND

Bitwise Operators: Work on integer values at the binary level.

result = 5 & 3  # Bitwise AND, result is 1

Can logical operators be used with non-boolean values in Python?

Yes, logical operators can be used with non-boolean values. Python evaluates non-boolean values in a boolean context:

and: Returns the first falsy value or the last value if all are truthy.

result = [] and "Non-empty"  # Returns []

or: Returns the first truthy value or the last value if all are falsy.

result = [] or "Non-empty"  # Returns "Non-empty"

not: Returns the boolean negation of the value.

result = not []  # Returns True

How to chain multiple logical conditions in Python?

You can chain multiple logical conditions using and, or, and not operators:

result = (5 > 3) and (8 > 5) or (2 < 1)  # Evaluates to True

Logical conditions are evaluated from left to right, with precedence rules applying as per the operator hierarchy.

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• Python
• Python-Operators

Practice Tags :

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