If Else

Sometimes a condition is true, and sometimes it is false.

What if you want your program to do one thing when the answer is true, and another thing when the answer is false?

That is where if else is useful.

What Is If Else?

Use if when something should happen only when a condition is true.

Use else when you want a different action when the condition is false.

age = 16

if age >= 18:
    print("You can vote")
else:
    print("You are too young to vote")

How It Works

Let’s break it down:

• Python checks if age >= 18
• If true, it prints the first message
• If false, it prints the message under else

Only one block will run.

Why Else Is Helpful

Without else, nothing happens when the condition is false.

With else, your program always gives a result.

Another Example

number = 7

if number % 2 == 0:
    print("Even number")
else:
    print("Odd number")

The Colon and Indentation

Both if and else need a colon :.

The code under each block must be indented.

if condition:
    print("True")

else:
    print("False")

Code Along

password = "python123"

if password == "python123":
    print("Access granted")
else:
    print("Wrong password")

Mini Challenge

Build a pass or fail checker.

Steps:

• Ask the user to enter a test score
• If the score is 50 or more, print:
  You passed
• Otherwise, print:
  You failed

Real World Use Case

Apps use if else to check login details, payment success, subscription status, and many other decisions.

Quiz

1. When does the else block run?
2. Can both if and else run at the same time?
3. Why is indentation important?
4. What will happen if the condition is false?

Assignment

Create a program that stores a number. If the number is positive, print Positive. Otherwise, print Not positive.

Summary

You learned how to use if else to make programs choose between two different actions.