Rust code shared from the playground

playground.rs

use std::fmt;

pub trait Join {
    fn join(&self) -> String;
}

impl<T: fmt::Display> Join for [T] {
    fn join(&self) -> String {
        self.iter()
            .map(|a| format!("{}", a))
            .collect::<Vec<_>>()
            .concat()
    }
}

fn main() {
    let a = [1,2,3];
    println!("{}", &a.join());
}