Learning If Statements

What is an If Statement?

An if statement allows your program to make decisions. It checks whether a condition is true or false and runs a block of code accordingly.

Basic Syntax of an If Statement

if condition:

    # Code to run if the condition is true

Example:

temperature = 25

if temperature > 20:

    print("It's a warm day!")

Output:
It's a warm day!

Indentations and Blocks

Indentation is crucial in Python. It determines which code belongs to a specific block.

Example:

if True:

    print("This is inside the block.")  # Indented

print("This is outside the block.")     # Not indented

Common Error:

If you forget to indent properly, Python will show an error:

if True:

print("This will cause an error!")  # No indentation

If-Else Statement

An if-else statement allows you to provide an alternative block of code if the condition is false.

Syntax:

if condition:

    # Code if condition is true

else:

    # Code if condition is false

Example:

temperature = 15

if temperature > 20:

    print("It's a warm day!")

else:

    print("It's a cool day.")

Output:
It's a cool day.

Elif Statement

Use elif when you need to check multiple conditions. It stands for "else if."

Syntax:

if condition1:

    # Code if condition1 is true

elif condition2:

    # Code if condition2 is true

else:

    # Code if none of the conditions are true

Example:

temperature = 0

if temperature > 20:

    print("It's a warm day!")

elif temperature > 10:

    print("It's a cool day!")

else:

    print("It's a cold day!")

Output:
It's a cold day!

Practice Exercises

Exercise 1: Basic If

Write a program that checks if a number is positive and prints "The number is positive."

Exercise 2: If-Else

Write a program that asks for the user’s age. If the age is 18 or older, print "You can vote!" Otherwise, print "You are too young to vote."

Exercise 3: Elif

Write a program that asks for the number of hours you study daily:

• If it’s more than 6 hours, print "You’re a study master!"

• If it’s between 3 and 6 hours, print "Good job!"

• If it’s less than 3 hours, print "Try to study more."

Bonus Challenge

Write a program that asks the user for the current temperature. Based on the input:

• If it’s above 30°C, print "It’s hot!"

• If it’s between 20°C and 30°C, print "It’s warm."

• If it’s between 10°C and 20°C, print "It’s cool."

• Otherwise, print "It’s cold!"

Congratulations!

Now you know how to use if statements, if-else, and elif in Python. These are essential tools for controlling your program's flow and making decisions. Keep practicing to master this skill! 🎉