Rust If and Match

if is an expression: it can produce a value. match compares a value against patterns and must cover every case.

ExampleRust

fn main() {
    let score = 72;
    if score >= 90 {
        println!("A");
    } else if score >= 70 {
        println!("B");
    } else {
        println!("C");
    }

    let result = if score >= 50 { "pass" } else { "fail" };
    println!("{}", result);

    let day = 3;
    let name = match day {
        1 => "Monday",
        2 | 3 => "Tuesday or Wednesday",
        4..=5 => "Late week",
        _ => "Weekend",
    };
    println!("{}", name);
}

Output

B
pass
Tuesday or Wednesday

The _ pattern matches anything left over. Rust forces match to be exhaustive, so you cannot forget a case.

Quick check

What must a match expression do?

Cover every possible caseUse only numbersAlways have two arms

Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.

Tip: use the left and right arrow keys to move between lessons.