Logical operators in Python

Examples

1) Both numbers are even

n = 4
m = 8
if n % 2 == 0 and m % 2 == 0:
    print("Both are even")

2) At least one number ends with 0

a = 25
b = 40
if a % 10 == 0 or b % 10 == 0:
    print("At least one ends with 0")

3) Positive and non-negative check

a = 5
b = 0
if a > 0 and not (b < 0):
    print("a is positive and b is non-negative")

# Equivalent without 'not'
if a > 0 and b >= 0:
    print("a is positive and b is non-negative")

Truth tables

and operator:

or operator:

not operator:

Tips

• Use parentheses (...) to make complex logic easier to read.
• Short-circuit evaluation: and stops if the first operand is False, or stops if the first operand is True.
• not flips the boolean value: not True → False, not False → True.

Quick practice

1. Check if both entered numbers are positive.
2. Check if at least one of the numbers is divisible by 5.
3. Check if a number is not between 10 and 20 (inclusive).

# 1) Both positive
a, b = map(int, input().split())
print(a > 0 and b > 0)

# 2) At least one divisible by 5
a, b = map(int, input().split())
print(a % 5 == 0 or b % 5 == 0)

# 3) Not between 10 and 20 inclusive
n = int(input())
print(not (10 <= n <= 20))