Handling errors with match in Rust - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the match statement do when handling errors in Rust?

It checks the result of an operation and lets you handle different cases, like Ok for success and Err for errors, by matching on these variants.

beginner

How do you access the value inside an Ok variant using match?

You use a pattern like Ok(value) in the match arm to get the successful result stored in value.

beginner

What is the purpose of the Err(e) pattern in a match statement?

It catches the error case and lets you handle or report the error stored in e.

intermediate

Why is using match for error handling better than just unwrapping?

Because match lets you handle errors gracefully without crashing the program, unlike unwrap() which panics on errors.

beginner

Write a simple match statement to handle a Result<String, &str> that prints the string on success or prints the error message on failure.

let result: Result<String, &str> = Ok("Hello".to_string());

match result {
    Ok(text) => println!("Success: {}", text),
    Err(e) => println!("Error: {}", e),
}

What does match do when used with a Result type in Rust?

A It ignores errors silently.

B It automatically fixes errors.

C It converts errors into success values.

D It lets you handle both success and error cases separately.

The match statement lets you write code for both Ok and Err cases explicitly.

Which pattern matches the error variant in a Result?

A Ok(value)

B Some(value)

C Err(e)

D None

Err(e) matches the error variant and binds the error to e.

What happens if you use unwrap() on an Err value?

A Panics and crashes the program.

B Converts error to success automatically.

C Ignores the error and continues.

D Returns the error value.

unwrap() panics if the Result is an Err, causing the program to crash.

In a match statement, how do you bind the success value of a Result to a variable?

A Ok(value)

B Err(value)

C Some(value)

D None

The pattern Ok(value) binds the success value to value.

Why is handling errors with match considered good practice?

A Because it hides errors from users.

B Because it forces you to handle all possible cases explicitly.

C Because it makes the program run faster.

D Because it automatically fixes bugs.

match requires you to handle every case, making your program more reliable.

Explain how to use match to handle a Result in Rust.

Think about how you separate success and error cases.

Describe why using match for error handling is safer than using unwrap().

Consider what happens when an error occurs.