Trait count_where::CountWhere

pub trait CountWhere: Iterator {
    fn count_where<P: FnMut(&Self::Item) -> bool>(self, predicate: P) -> usize;
}

trait extension that adds count_where functionality to iterators.

Required methods

fn count_where<P: FnMut(&Self::Item) -> bool>(self, predicate: P) -> usize

Implementors

impl<I> CountWhereExt for I where
    I: Iterator,
    I::Item: Copy + Clone + Ord, 

fn count_where<P: FnMut(&Self::Item) -> bool>(self, predicate: P) -> usize

count elements matching given predicate.

Example

let numbers = [5, 5, 5, 2, 1]; assert_eq!(3, numbers.iter().count_where(|n| **n == 5));