Try–except–finally behavior in Python - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the try block in Python?

The try block contains code that might cause an error. Python runs this code and watches for exceptions (errors) to handle them gracefully.

beginner

What happens when an exception occurs inside a try block?

Python stops running the try block and looks for a matching except block to handle the error. If found, it runs the except block code.

beginner

What is the role of the finally block in a try-except structure?

The finally block runs code no matter what happened before—whether an error occurred or not. It is often used to clean up resources like files or connections.

intermediate

Can the finally block change the program's return value if it contains a return statement?

Yes. If the finally block has a return statement, it overrides any previous return from the try or except blocks.

intermediate

What happens if an exception is not caught by any except block?

If no except block matches the exception, the error propagates up and may crash the program after the finally block runs.

Which block always runs regardless of exceptions?

A else

B except

C try

D finally

The finally block always runs, whether an exception occurred or not.

If an exception occurs and is caught, which blocks run?

A try and except only

B try, except, and finally

C except and finally only

D try and finally only

When an exception is caught, try runs until the error, then except runs, and finally finally runs.

What happens if the finally block contains a return statement?

A It causes an error

B It is ignored

C It overrides any previous return

D It runs only if no exception occurs

A return in finally overrides any return from try or except.

Which block handles exceptions?

A except

B finally

C try

D else

The except block catches and handles exceptions.

If no exception occurs, which blocks run?

A try and finally

B except only

C except and finally

D try and except

If no exception occurs, try runs fully, then finally runs.

Explain the flow of execution in a try-except-finally structure when an exception occurs.

Think about what happens step-by-step when an error is found.

Describe what happens if the finally block contains a return statement.

Consider how return statements in finally affect the function's output.