Structs, Enums and Traits

Rust Pattern Matching with match

Compare a value against values, ranges, tuples and guards, and let the compiler check you covered everything.

Intermediate
3 min read
1 runnable example

What you'll learn

match arms
Ranges, | and guards
if let

Run code →

match n

0"zero"

1 | 2 | 3"small"

4..=9"medium"

_"large"

The first pattern that fits wins

match compares a value with a list of patterns and runs the first one that fits. Patterns can be single values, several values, ranges, tuples, or a name that catches everything else.

1 | 2 | 3 matches any of the three values and 4..=9 matches a range. n if n < 0 is a guard: the pattern matches only when the condition is true. _ catches everything that is left. if let is a short match for a single pattern.

Key points

1 | 2 | 3 matches any of the three.
4..=9 matches a range.
_ catches everything else.

Runnable Rust example

Rust

Run code →

main.rs

fn classify(n: i32) -> &'static str {
    match n {
        0 => "zero",
        1 | 2 | 3 => "small",
        4..=9 => "medium",
        n if n < 0 => "negative",
        _ => "large",
    }
}

fn main() {
    for n in [0, 2, 7, -5, 42] {
        println!("{n}: {}", classify(n));
    }

    let point = (0, 8);
    match point {
        (0, y) => println!("on the y axis at {y}"),
        (x, 0) => println!("on the x axis at {x}"),
        (x, y) => println!("at ({x}, {y})"),
    }

    let maybe = Some(3);
    if let Some(value) = maybe {
        println!("got {value}");
    }
}

Get a Run button for this example Result of running the code

0: zero
2: small
7: medium
-5: negative
42: large
on the y axis at 8
got 3

Practice

Open the example in the online compiler, change a value or add a line, and predict the output before you run it. Then break the code on purpose and read the compiler's message.

Finished this lesson?

Mark it as learned to track your progress.

Next: Temperature Converter →

Practice with a challenge

Use what this lesson covers to solve a real problem. Each challenge runs in your browser with instant tests and an AI review.

All challenges