grouping-by

This library provides users the possibility of grouping their iterators by any function. It is similar to C# IEnumerable.GroupBy or Java Collectors.groupingBy

Example:

#[derive(Debug, Clone)]
struct Point {
   x: i32,
   y: i32,
}
let array: [Point; 4] = [
       Point { x: 1, y: 2 },
       Point { x: 1, y: 3 },
       Point { x: 2, y: 2 },
       Point { x: 2, y: 2 },
];
assert_eq!(
    [
        (1, vec![&Point { x: 1, y: 2 }, &Point { x: 1, y: 3 }]),
        (2, vec![&Point { x: 2, y: 2 }, &Point { x: 2, y: 2 }])
    ]
    .iter()
    .cloned()
    .collect::<HashMap<i32, Vec<&Point>>>(),
    array.iter().grouping_by(|point| point.x)
);