comprehensive-rust/src/pattern-matching/destructuring-arrays.md

Destructuring Arrays

You can destructure arrays, tuples, and slices by matching on their elements:

{{#include ../../third_party/rust-by-example/destructuring-arrays.rs}}

• Destructuring of slices of unknown length also works with patterns of fixed length.

  fn main() {
      inspect(&[0, -2, 3]);
      inspect(&[0, -2, 3, 4]);
  }
  
  #[rustfmt::skip]
  fn inspect(slice: &[i32]) {
      println!("Tell me about {slice:?}");
      match slice {
          &[0, y, z] => println!("First is 0, y = {y}, and z = {z}"),
          &[1, ..]   => println!("First is 1 and the rest were ignored"),
          _          => println!("All elements were ignored"),
      }
  }
  

• Create a new pattern using _ to represent an element.

• Add more values to the array.

• Point out that how .. will expand to account for different number of elements.

• Show matching against the tail with patterns [.., b] and [a@..,b]