Trait tantivy_common::GroupByIteratorExtended

pub trait GroupByIteratorExtended: Iterator {
    // Provided method
    fn group_by<K, F>(self, key: F) -> GroupByIterator<Self, F, K>
       where Self: Sized,
             F: FnMut(&Self::Item) -> K,
             K: PartialEq + Clone,
             Self::Item: Clone { ... }
}

Provided Methods

fn group_by<K, F>(self, key: F) -> GroupByIterator<Self, F, K>

where Self: Sized, F: FnMut(&Self::Item) -> K, K: PartialEq + Clone, Self::Item: Clone,

Return an Iterator that groups iterator elements. Consecutive elements that map to the same key are assigned to the same group.

The returned Iterator item is (K, impl Iterator), where Iterator are the items of the group.

use tantivy_common::GroupByIteratorExtended;

// group data into blocks of larger than zero or not.
let data: Vec<i32> = vec![1, 3, -2, -2, 1, 0, 1, 2];
// groups:               |---->|------>|--------->|

let mut data_grouped = Vec::new();
// Note: group is an iterator
for (key, group) in data.into_iter().group_by(|val| *val >= 0) {
    data_grouped.push((key, group.collect()));
}
assert_eq!(data_grouped, vec![(true, vec![1, 3]), (false, vec![-2, -2]), (true, vec![1, 0, 1, 2])]);

Implementors

impl<I: Iterator> GroupByIteratorExtended for I