Logical operators in Python are used to perform logical operations on boolean values. These operators play a critical role in decision-making and conditional statements in Python programming.

What Are Logical Operators in Python?

Python has three main logical operators:

• and: Returns True if both conditions are true.
• or: Returns True if at least one condition is true.
• not: Reverses the boolean value of a condition.

These operators are essential for creating more complex conditional expressions in your Python code.

1. and Operator

The and operator evaluates two conditions and returns True only if both conditions are true.

Syntax:

condition1 and condition2

Example:

age = 25
is_employed = True

if age > 18 and is_employed:
    print("Eligible for the job")
else:
    print("Not eligible for the job")

Output:

Eligible for the job

2. or Operator

The or operator evaluates two conditions and returns True if at least one condition is true.

Syntax:

condition1 or condition2

Example:

has_experience = False
has_certificate = True

if has_experience or has_certificate:
    print("You qualify for the course")
else:
    print("You need to meet at least one requirement")

Output:

You qualify for the course

3. not Operator

The not operator reverses the result of a condition. If a condition is True, it returns False and vice versa.

Syntax:

not condition

Example:

is_active = False

if not is_active:
    print("Account is inactive")
else:
    print("Account is active")

Output:

Account is inactive

Combining Logical Operators

Logical operators can be combined to form complex conditions.

Example:

age = 30
income = 50000
has_good_credit = True

if age > 25 and income > 40000 and has_good_credit:
    print("Loan approved")
else:
    print("Loan not approved")

Output:

Loan approved

Truth Table for Logical Operators

Practical Use Cases

1. Access Control:

username = "admin"
password = "1234" 
if username == "admin" and password == "1234": 
  print("Login successful") 
else: 
  print("Invalid credentials")

2. Game Development:

player_alive = True
has_shield = False
if player_alive and not has_shield: 
  print("You are vulnerable to attacks!")

3. Data Validation:

email = "user@example.com" 
is_verified = False 
if email and not is_verified: 
	print("Please verify your email")

Common Mistakes with Logical Operators

1. Using & Instead of and:
   • In Python, & is a bitwise operator, not a logical operator. Use and for logical operations.
2. Order of Evaluation:
   • Logical operators follow a precedence order: not > and > or. Use parentheses for clarity:

if (x > 5 and y < 10) or z == 3:
  print("Condition met")

Mini-Project: Login Validation System

Objective:

Create a Python program that validates a user’s login using logical operators.

Code:

stored_username = "admin"
stored_password = "secure123"

input_username = input("Enter your username: ")
input_password = input("Enter your password: ")

if input_username == stored_username and input_password == stored_password:
    print("Welcome, Admin!")
else:
    print("Invalid username or password")

Sample Run:

Enter your username: admin
Enter your password: secure123
Welcome, Admin!

Interview Questions

1. Google

Q: How does Python handle precedence in logical operators?
A: Logical operators follow this precedence: not > and > or.

2. Amazon

Q: Can you use logical operators with non-boolean values?
A: Yes, Python evaluates non-boolean values based on their truthy or falsy nature. For example:

result = "" or "Default"
print(result)  # Output: Default

3. TCS

Q: How do you optimize nested logical conditions?
A: Simplify conditions by combining expressions and using parentheses to clarify precedence.

4. Infosys

Q: Explain short-circuit evaluation in Python logical operators.
A: Python stops evaluating conditions as soon as the result is determined.

For example, in True or False, the second condition is not evaluated.

5. Zoho

Q: Write a code snippet to check if a number is within a specific range using logical operators.
A:

num = 15
if num > 10 and num < 20:
    print("Number is within range")
else:
    print("Number is out of range")

Conclusion

Logical operators in Python are simple yet powerful tools for building conditional logic. Mastering them enables developers to write efficient, readable, and robust code. Practice combining these operators to handle complex scenarios effectively!ese operators, you can write efficient and clear code to handle complex logic. Whether you’re a beginner or preparing for interviews, understanding these concepts is essential.

logical operators

Start Quiz

Question

Your answer:

Correct answer:

Next

You got {{SCORE_CORRECT}} out of {{SCORE_TOTAL}}

Your Answers