With statement execution flow in Python - Mini Project: Build & Apply

With Statement Execution Flow

📖 Scenario: Imagine you have a special box that you want to open and close safely. In programming, the with statement helps you open this box, do something inside, and then close it automatically, even if something goes wrong.

🎯 Goal: You will create a simple class that acts like this special box. Then, you will use the with statement to open the box, print messages when opening and closing, and see how the flow works.

📋 What You'll Learn

Create a class called SpecialBox with __enter__ and __exit__ methods

In __enter__, print 'Box is opened' and return self

In __exit__, print 'Box is closed'

Use a with statement with SpecialBox() and print 'Inside the box' inside the block

Print the messages in the correct order to show the flow of the with statement

💡 Why This Matters

🌍 Real World

The <code>with</code> statement is used to manage resources like files, network connections, or locks, ensuring they are properly opened and closed.

💼 Career

Understanding <code>with</code> helps you write reliable code that avoids resource leaks, a key skill for software developers and engineers.

1

Create the SpecialBox class with __enter__ method

Create a class called SpecialBox with a method __enter__ that prints 'Box is opened' and returns self.

Python

# Create the SpecialBox class with __enter__ method
# Your code here

Need a hint?

The __enter__ method runs when the with block starts.

2

Add the __exit__ method to SpecialBox

Add a method __exit__ to the SpecialBox class that prints 'Box is closed'. It should accept four parameters: self, exc_type, exc_value, and traceback.

Python

class SpecialBox:
    def __enter__(self):
        print('Box is opened')
        return self

# Add the __exit__ method below
# Your code here

Need a hint?

The __exit__ method runs when the with block ends, even if there is an error.

3

Use the with statement with SpecialBox

Write a with statement using SpecialBox() as box. Inside the block, print 'Inside the box'.

Python

class SpecialBox:
    def __enter__(self):
        print('Box is opened')
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        print('Box is closed')

# Use the with statement with SpecialBox
# Your code here

Need a hint?

The with statement automatically calls __enter__ and __exit__.

4

Print the flow of the with statement

Run the program and print the messages showing the order: Box is opened, Inside the box, and Box is closed.

Python

class SpecialBox:
    def __enter__(self):
        print('Box is opened')
        return self

    def __exit__(self, exc_type, exc_value, traceback):
        print('Box is closed')

with SpecialBox() as box:
    print('Inside the box')

# Run the program to see the output

Need a hint?

Run the code to see the messages printed in order.