Function difference 

pub fn difference<T: Clone + Eq + Hash>(a: &[T], b: &[T]) -> Vec<T>

Returns elements that are in a but not in b.

Example

use d3rs::array::difference;

let a = vec![1, 2, 3, 4, 5];
let b = vec![3, 4, 5, 6, 7];
assert_eq!(difference(&a, &b), vec![1, 2]);