The Option type (null safety)

This lesson covers the Option type, which safely represents "there may or may not be a value here".

Rust has no concept of null. Instead you use Option<T>, writing Some(value) when there is a value and None when there is not.

In the sample code, a find_score function that searches an array returns Option<i32>, and match handles the found and not-found cases safely.

A common early stumble is trying to use the contents of an Option directly and hitting an error. You have to check for Some or None before taking the value out — which is how Rust turns null-related runtime errors into compile-time ones.

In professional work, Option appears in almost every operation where the data might not exist, making it one of Rust's central safety features.

📖 Reference code

fn find_score(scores: &[i32], target: i32) -> Option<i32> {
    for &s in scores {
        if s == target {
            return Some(s);
        }
    }
    None
}

fn main() {
    let scores = vec![80, 95, 70];
    match find_score(&scores, 95) {
        Some(s) => println!("Found: {}", s),
        None => println!("Not found"),
    }
}

✍️ Your code

Type your code, then press "Run"

🧪 This site can't compile or run Rust directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser — nothing is sent anywhere).