Trait grabbag::iter::GroupByIterator [−] [src]

pub trait GroupByIterator<E>: Iterator<Item=E> + Sized {
    fn group_by<GroupFn: FnMut(&E) -> G, G>(self, group: GroupFn) -> GroupBy<Self, GroupFn, E, G> { ... }
}

Sequence of iterators containing successive elements of the subject which have the same group according to a group function.

Provided Methods

fn group_by<GroupFn: FnMut(&E) -> G, G>(self, group: GroupFn) -> GroupBy<Self, GroupFn, E, G>

Creates an iterator that yields a succession of (group, sub_iterator) pairs. Each sub_iterator yields successive elements of the input iterator that have the same group. An element's group is computed using the f closure.

For example:

let v = vec![7usize, 5, 6, 2, 4, 7, 6, 1, 6, 4, 4, 6, 0, 0, 8, 8, 6, 1, 8, 7];
let is_even = |n: &usize| if *n & 1 == 0 { true } else { false };
for (even, mut ns) in v.into_iter().group_by(is_even) {
    println!("{}...", if even { "Evens" } else { "Odds" });
    for n in ns {
        println!(" - {}", n);
    }
}

Implementors