Function bincount 

pub fn bincount<T>(xs: &[T], k: usize) -> Vec<usize>
where
    T: Clone + Into<usize>,

Bins the entries in xs into k bins.

Example

let xs: Vec<usize> = vec![0, 0, 1, 2, 2, 2, 3];

assert_eq!(bincount(&xs, 4), vec![2, 1, 3, 1]);