Using unwrap and expect in Rust - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to unwrap the Option value safely.

Rust

let some_number = Some(10);
let number = some_number.[1]();
println!("Number: {}", number);

Drag options to blanks, or click blank then click option'

Aunwrap_or_else

Bexpect

Cunwrap_or

Dunwrap

Attempts:

3 left

💡 Hint

Common Mistakes

Using expect without a message causes a compile error.

Using unwrap_or requires a default value argument.

The unwrap() method extracts the value inside Some if it exists, otherwise it panics.

2fill in blank

medium

Complete the code to unwrap the Option with a custom panic message.

Rust

let some_text = Some("hello");
let text = some_text.[1]("No text found!");
println!("Text: {}", text);

Drag options to blanks, or click blank then click option'

Aexpect

Bunwrap_or

Cunwrap

Dunwrap_or_else

Attempts:

3 left

💡 Hint

Common Mistakes

Using unwrap does not allow a custom message.

Using unwrap_or requires a default value, not a message.

The expect() method unwraps the Option and shows the given message if it is None.

3fill in blank

hard

Fix the error in unwrapping the Result value with expect.

Rust

let result: Result<i32, &str> = Ok(5);
let value = result.[1]("Failed to get value");
println!("Value: {}", value);

Drag options to blanks, or click blank then click option'

Aunwrap_or

Bexpect

Cunwrap_err

Dunwrap

Attempts:

3 left

💡 Hint

Common Mistakes

Using unwrap_err unwraps the error, not the success value.

Using unwrap_or requires a default value, not a message.

The expect() method unwraps the Ok value or panics with the given message if it is Err.

4fill in blank

hard

Fill both blanks to unwrap an Option and provide a custom panic message.

Rust

let maybe_value = Some(42);
let value = maybe_value.[1]("[2] not found");
println!("Value is {}", value);

Drag options to blanks, or click blank then click option'

Aexpect

Bunwrap

COption

DResult

Attempts:

3 left

💡 Hint

Common Mistakes

Using unwrap instead of expect for custom messages.

Using Result instead of Option in the message.

Use expect to unwrap the Option with a message. The message should mention Option to clarify the error source.

5fill in blank

hard

Fill all three blanks to unwrap a Result and handle the error with a custom message.

Rust

let res: Result<&str, &str> = Err("error");
let val = res.[1]("[2] failed");
println!("Value: {}", [3]);

Drag options to blanks, or click blank then click option'

Aunwrap_or

Bexpect

Cval

Dunwrap

Attempts:

3 left

💡 Hint

Common Mistakes

Using unwrap_or instead of expect for custom messages.

Printing the wrong variable name.

Use expect to unwrap the Result with a message. The message includes unwrap to indicate the failure point. Finally, print the unwrapped value val.