__name__ and __main__ behavior in Python - Mini Project: Build & Apply

__name__ and __main__ behavior

📖 Scenario: Imagine you are creating a Python script that can be used both as a program and as a module imported by other scripts. You want to control what code runs only when the script is executed directly.

🎯 Goal: Build a Python script that defines a function and uses the if __name__ == '__main__' check to run code only when the script is run directly, not when imported.

📋 What You'll Learn

Create a function called greet that prints a greeting message.

Create a variable called message with the value 'Hello from the function!'.

Use the if __name__ == '__main__' statement to call the greet function only when the script is run directly.

Print 'Script is being run directly' inside the if __name__ == '__main__' block.

💡 Why This Matters

🌍 Real World

Many Python scripts are written to be both reusable modules and standalone programs. Using <code>if __name__ == '__main__'</code> helps control code execution depending on how the script is used.

💼 Career

Understanding this concept is essential for writing clean, reusable Python code in software development, automation scripts, and data science projects.

1

Create the greet function and message variable

Create a function called greet that prints the variable message. Also, create a variable called message with the value 'Hello from the function!'.

Python

# Create the message variable and greet function
# Your code here

Need a hint?

Define message first, then define greet() that prints message.

2

Add the if __name__ == '__main__' block

Add the if __name__ == '__main__' statement below the function. Inside this block, print 'Script is being run directly'.

Python

message = 'Hello from the function!'

def greet():
    print(message)

# Add the if __name__ == '__main__' block below
# Your code here

Need a hint?

Use the exact line if __name__ == '__main__': and indent the print statement inside it.

3

Call the greet function inside the if __name__ == '__main__' block

Inside the if __name__ == '__main__' block, call the greet() function after the print statement.

Python

message = 'Hello from the function!'

def greet():
    print(message)

if __name__ == '__main__':
    print('Script is being run directly')
    # Call greet() here
    # Your code here

Need a hint?

Simply add greet() indented inside the if __name__ == '__main__' block after the print.

4

Print the output when running the script

Run the script and print the output. The output should show Script is being run directly followed by Hello from the function!.

Python

# Run the script and print the output
# Your code here

Need a hint?

Just run the script as is. The output should match exactly.