id	title	sidebar_label	sidebar_position	tags
python-conditional-statements	Conditional Statements in Python	Conditional Statements in Python	9	Python Conditional Statements if else elif Control Flow Python Syntax

Conditional Statements in Python

Conditional statements in Python allow you to make decisions in your code. They control the flow of execution depending on whether a given condition is True or False.

---

The if Statement

The simplest conditional statement is the if statement.

Syntax:

if condition:
    # block of code

Example:

x = 10
if x > 5:
    print("x is greater than 5")

---

The if...else Statement

The else block runs when the if condition is False.

x = 3
if x > 5:
    print("x is greater than 5")
else:
    print("x is less than or equal to 5")

Output:

x is less than or equal to 5

---

The if...elif...else Statement

elif stands for "else if". It lets you check multiple conditions.

score = 85

if score >= 90:
    print("Grade A")
elif score >= 75:
    print("Grade B")
elif score >= 60:
    print("Grade C")
else:
    print("Grade D")

---

Nested if Statements

You can put an if statement inside another if statement.

x = 15
if x > 10:
    if x < 20:
        print("x is between 10 and 20")

---

Conditional Expressions (Ternary Operator)

Python has a shorter way to write if...else using ternary expressions.

age = 18
status = "Adult" if age >= 18 else "Minor"
print(status)

Output:

Adult

---

Logical Operators in Conditions

You can combine multiple conditions using and, or, and not.

x = 7
if x > 5 and x < 10:
    print("x is between 5 and 10")

if x < 5 or x > 10:
    print("x is outside 5 to 10")

if not x == 8:
    print("x is not 8")

---

Comparing Multiple Values

You can check if a value exists in a sequence using in.

fruits = ["apple", "banana", "cherry"]
if "apple" in fruits:
    print("Apple is in the list")

---

Indentation Rules

In Python, indentation is important for defining code blocks.

if True:
    print("This is indented correctly")
    print("Still inside if block")
print("Outside if block")

---

Summary Table

Statement Type	Description
if	Executes a block if condition is True
if...else	Executes else block if condition is False
if...elif...else	Checks multiple conditions
Nested if	if inside another if
Ternary Expression	Short form of if...else

Practice Questions

1. Positive / Negative / Zero Checker

Write a Python program that takes a number as input and checks whether it is positive, negative, or zero.

2. Odd or Even

Write a Python program to check whether a number is even or odd.

3. Age Eligibility for Voting

Write a program to take a person’s age as input and check if they are eligible to vote (18 years or older).

4. Largest of Two Numbers

Write a Python program that takes two numbers as input and prints the larger number using conditional statements.

5. Largest of Three Numbers

Write a Python program to find the largest among three numbers entered by the user using if, elif, and else.

6. Grading System

Write a Python program to take a student's marks as input and print the grade according to the following criteria:

• Marks ≥ 90 → Grade A
• Marks ≥ 75 and < 90 → Grade B
• Marks ≥ 50 and < 75 → Grade C
• Marks < 50 → Grade F

7. Leap Year Checker

Write a program to check whether a given year is a leap year or not. (Hint: A year is leap if divisible by 4 but not 100, or divisible by 400)

8. Nested If — Number Range Checker

Write a program that takes a number as input and:

• Checks if it's positive.
• If positive, further checks if it is less than 10, between 10 and 50, or greater than 50.

9. Character Classification

Write a program to input a single character and check whether it is:

• a vowel,
• a consonant,
• a digit, or
• a special character.

10. Login Authentication (Simple)

Write a program that asks the user to enter a username and password.

• If the username is "admin" and the password is "12345", print “Login Successful”.
• Otherwise, print “Invalid credentials”.

Conclusion

Conditional statements are essential for decision-making in programs. Mastering if, elif, and else allows you to control your program's logic effectively.