How do I find the index of an element in an array, vector or slice?

I need to find an index of an element in a vector of strings. This is what I got so far:

fn main() {
    let test: Vec = vec![
        "one".to_string(),
        "two".to_string(),
        "three".to_string(),
        "four".to_string(),
    ];

    let index: i32 = test
        .iter()
        .enumerate()
        .find(|&r| r.1.to_string() == "two".to_string())
        .unwrap()
        .0;
}

It produces an error:

error[E0308]: mismatched types
--> src/main.rs:9:22
|
9 | let index: i32 = test
| ______________________^
10 | | .iter()
11 | | .enumerate()
12 | | .find(|&r| r.1.to_string() == "two".to_string())
13 | | .unwrap()
14 | | .0;
| |__________^ expected i32, found usize


I assume that's because enumerate() returns a tuple of (usize, _) (correct me if I'm wrong), but how do I convert usize to i32 here? If there is a better approach, I'm open to suggestions.

I think you should look at the position method instead.

fn main() {
    let test = vec!["one", "two", "three"];
    let index = test.iter().position(|&r| r == "two").unwrap();
    println!("{}", index);
}

You can test it here.

Note that this works for any iterator, so it can be used for vectors, arrays, and slices, all of which produce iterators.

Stack Overflow Q#30558246, score: 302