zacharygolba / peek-nth

An iterator adapter that allows you to efficiently peek the nth item of an iterator.

peek-nth

An iterator adapter that allows you to efficiently peek the nth item of an iterator.

Itermediate values are memoized and heap allocations are avoided when possible.

Installation

First, add peek-nth to the dependencies section of your Cargo.toml:

[dependencies]
peek-nth = "0.2"

Next, add the following snippet to the entry point of your crate (lib.rs or main.rs):

extern crate peek_nth;

Usage

extern crate peek_nth;

use peek_nth::IteratorExt;

fn main() {
    let mut iter = "Hello, world!".chars().peekable_nth();

    assert_eq!(iter.peek_nth(4), Some(&'o')); // Cache Miss
    assert_eq!(iter.peek_nth(3), Some(&'l')); // Cache Hit
    assert_eq!(iter.peek_nth(2), Some(&'l')); // Cache Hit
    assert_eq!(iter.peek_nth(1), Some(&'e')); // Cache Hit
    assert_eq!(iter.peek_nth(0), Some(&'H')); // Cache Hit
    assert_eq!(iter.peek_nth(7), Some(&'w')); // Cache Miss

    assert_eq!(iter.collect::<String>(), "Hello, world!");
}

License

Licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.