take.rs

take.rs

#[test]
fn take_works_well() {
    let a: &[i32] = &[1,2,3];
    let t = a.take(2);
    assert_eq!(t.len(), 2);
    assert_eq!(t[0], 1);
    assert_eq!(t[1], 2);
}

#[test]
fn take_last_works_well() {
    let a: &[i32] = &[1,2,3];
    let t = a.take_last(2);
    assert_eq!(t.len(), 2);
    assert_eq!(t[0], 2);
    assert_eq!(t[1], 3);
}

trait Take<T> {
    fn take(&self, n: usize) -> &[T];
    fn take_last(&self, n: usize) -> &[T];
}

impl<T> Take<T> for [T] {
    fn take(&self, n: usize) -> &[T] {
        return &self[0..n];
    }

    fn take_last(&self, n: usize) -> &[T] {
        let len = self.len();
        return &self[(len-n)..len];
    }
}