Rust Vec<String> find example

find_string_example.rs

fn main() {
    let needle = "list".to_string();
    let haystack = ["some".to_string(), "long".to_string(), "list".to_string(), "of".to_string(), "strings".to_string()].to_vec();

    if let Some(str) = haystack.iter().find(|&s| *s == needle) {
        println!("{}", needle);
    } else {
        println!("Nothing there...");
    }
}

contains is definitely the idiomatic approach. Also, you can avoid repeating .to_string(), and you can rely more on type inference:

fn main() {
    let needle = "list".into();
    let haystack: Vec<_> = vec!["some", "long", "list", "of", "strings"]
        .into_iter()
        .map(String::from)
        .collect();
    if haystack.contains(&needle) {
        println!("{}", needle);
    } else {
        println!("not found");
    }
}

And if you're going to do membership tests often, consider a set rather than a vector.

Thanks all of you for the ideas!

Yup as I learned on StackOverflow, using contains seems a lot simpler and cleaner in this example. Using into_iter will also work, but isn't what I need in my app because I don't want to move the data out.

And thanks for the type inference tip - yes much cleaner.

The deeper issue for me is that Rust's & and && syntax can be very confusing, especially with iterators and closures. Will just take some getting used to I suppose :)