If you are here for the first time, I don’t usually write this kind of post, but it was pretty hard to find a simple code to fold a HasMap in rust.

In this use case, I had a hash map with server names and a boolean indicating if the server ack the message or not.

use std::collections::HashMap;

fn main() {
    // inits hash_map
    let mut hash = HashMap::new();
    // Add itens to the hash map
    hash.insert(String::from("servers:1"), true);
    hash.insert(String::from("servers:2"), true);
    hash.insert(String::from("servers:3"), false);

		// Fold the hashmap
    let string_result = hash.into_iter().fold(
        String::from(""), /*Initial value*/
        |accumulator: String, value: (String, bool) /* each value*/| {
            String::from(format!(
                "{}, {}:{}",
                accumulator.to_owned(),
                value.0.to_owned(),// Access props with number fields
                value.1.to_owned()
            ))
        },
    );

    println!("{}", string_result);
}

Conclusion

I hope it can help you if you get here via searching on the internet, see you in the next one.