find_all is capable of finding all indexes of elements where a given predicate is met and therefore aims to be a simple alternative with (nearly) identical interface to the find method (this difference being returning an Option<Vec<usize>> instead of Option<usize>)
use find_all::FindAll;
let test_data = [1, 2, 3, 4, 1, 1, 1, 1];
let indexes = test_data.iter().find_all(|num: &&i32| **num == 9);
assert_eq!(indexes, None);
let indexes = test_data.iter().find_all(|num: &&i32| **num == 1);
assert_eq!(indexes, Some(vec![0,4,5,6,7]));License: GPL-3.0-only