iter.reduce(fn)

This crate gives Iterators a reduce function that is similar to fold but without an initial value. The function returns None if the iterator is empty and Some(value) otherwise. This matches the distinction between reduce and fold in Scala.

[dependencies]
reduce = "0.1"

Examples

use reduce::Reduce;

fn main() {
    // Reduce a non-empty iterator into Some(value)
    let v = vec![1usize, 2, 3, 4, 5];
    let sum = v.into_iter().reduce(|a, b| a + b);
    assert_eq!(Some(15), sum);

    // Reduce an empty iterator into None
    let v = Vec::<usize>::new();
    let sum = v.into_iter().reduce(|a, b| a + b);
    assert_eq!(None, sum);
}

License