Best practices for resource management in Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of using context manager with file handling

What is the output of this Python code snippet?

Python

with open('test.txt', 'w') as f:
    f.write('Hello')
print(f.closed)

A True

B False

C Raises a NameError

D None

💡 Hint

Think about what happens to the file after the with block ends.

The 'with' statement automatically closes the file after the block ends, so f.closed is True.

🧠 Conceptual

intermediate

Why use 'with' statement for resource management?

Which of the following best explains why using the 'with' statement is recommended for resource management in Python?

A It automatically handles opening and closing resources, even if errors occur.

B It makes the code run faster by caching resources.

C It allows resources to stay open indefinitely for reuse.

D It disables error messages related to resource usage.

💡 Hint

Think about what happens if an error occurs inside a 'with' block.

The 'with' statement ensures resources are properly closed even if exceptions happen, preventing leaks.

🔧 Debug

advanced

Identify the resource leak in this code

What is the main problem with this code snippet regarding resource management?

Python

def read_file(filename):
    f = open(filename, 'r')
    data = f.read()
    return data

content = read_file('data.txt')

A The file is opened in write mode instead of read mode.

B The file is closed too early before reading.

C The file is never closed, causing a resource leak.

D The function returns None instead of file content.

💡 Hint

Think about what happens to the file after reading.

The file is opened but never closed, which can exhaust system resources if done repeatedly.

📝 Syntax

advanced

Correct syntax for custom context manager

Which option correctly defines a custom context manager class in Python?

Python

class MyResource:
    def __enter__(self):
        print('Resource acquired')
        return self

    def __exit__(self, exc_type, exc_val, exc_tb):
        print('Resource released')

A

class MyResource:
    def enter(self):
        return self
    def exit(self, exc_type, exc_val, exc_tb):
        pass

B

class MyResource:
    def __enter__(self):
        return self
    def __exit__(self, exc_type, exc_val, exc_tb):
        pass

C

class MyResource:
    def __enter__(self):
        return self
    def __exit__(self):
        pass

D

class MyResource:
    def __enter__(self):
        return self
    def __exit__(self, exc_type, exc_val):
        pass

💡 Hint

Check the method names and parameters required for context managers.

The __enter__ and __exit__ methods must have exact names and __exit__ must accept 4 parameters.

🚀 Application

expert

Using contextlib to manage resources

Which option correctly uses the contextlib module to create a context manager that prints messages on enter and exit?

Python

from contextlib import contextmanager

@contextmanager
def managed_resource():
    print('Start')
    yield
    print('End')

A

with managed_resource():
    print('Inside')

# Output:
# Start
# End
# Inside

B

with managed_resource:
    print('Inside')

# Output:
# Start
# Inside
# End

C

with managed_resource():
    print('Inside')

# Output:
# Inside
# Start
# End

D

with managed_resource():
    print('Inside')

# Output:
# Start
# Inside
# End

💡 Hint

Remember to call the function to get the context manager object.

The context manager must be called with parentheses; the yield separates enter and exit code.