Rust logo
Rust 1.29.0-nightly
4f3c7a472

Patterns

There is a new edition of the book and this is an old link.

Patterns are a special syntax within Rust for matching against the structure of our types, complex or simple. A pattern is made up of some combination of literals; destructured arrays, enums, structs, or tuples; variables, wildcards, and placeholders. These pieces describe the “shape” of the data we’re working with.

let x = Some(5);
let y = 10;

match x {
    Some(50) => println!("Got 50"),
    Some(y) => println!("Matched, y = {:?}", y),
    _ => println!("Default case, x = {:?}", x),
}Run

Here are the relevant sections in the new and old books: