# Slice patterns

If you want to match against a slice or array, you can use `&` with the `slice_patterns` feature:

    #![feature(slice_patterns)]

    fn main() {
        let v = vec!["match_this", "1"];

        match &v[..] {
            &["match_this", second] => println!("The second element is {}", second),
            _ => {},
        }
    }Run

The `advanced_slice_patterns` gate lets you use `..` to indicate any number of elements inside a pattern matching a slice. This wildcard can only be used once for a given array. If there's an identifier before the `..`, the result of the slice will be bound to that name. For example:

    #![feature(advanced_slice_patterns, slice_patterns)]

    fn is_symmetric(list: &[u32]) -> bool {
        match list {
            &[] | &[_] => true,
            &[x, ref inside.., y] if x == y => is_symmetric(inside),
            _ => false
        }
    }

    fn main() {
        let sym = &[0, 1, 4, 2, 4, 1, 0];
        assert!(is_symmetric(sym));

        let not_sym = &[0, 1, 7, 2, 4, 1, 0];
        assert!(!is_symmetric(not_sym));
    }Run