Trait differential_dataflow::operators::group::Group [−] [src]

pub trait Group<G: Scope, K: Data, V: Data, R: Diff> where
    G::Timestamp: Lattice + Ord, {
    fn group<L, V2: Data, R2: Diff>(
        &self, 
        logic: L
    ) -> Collection<G, (K, V2), R2>
    where
        L: Fn(&K, &[(&V, R)], &mut Vec<(V2, R2)>) + 'static;
}

Extension trait for the group differential dataflow method.

Required Methods

Groups records by their first field, and applies reduction logic to the associated values.

Examples

extern crate timely;
extern crate differential_dataflow;

use differential_dataflow::input::Input;
use differential_dataflow::operators::Group;

fn main() {
    ::timely::example(|scope| {
        // report the first value for each group
        scope.new_collection_from(1 .. 10).1
             .map(|x| (x / 3, x))
             .group(|_key, src, dst| {
                 dst.push((*src[0].0, 1))
             });
    });
}

Implementors