Function itertools::join

pub fn join<I>(iterable: I, sep: &str) -> String where
    I: IntoIterator,
    I::Item: Display, 

Combine all iterator elements into one String, seperated by sep.

IntoIterator enabled version of iterable.join(sep).

use itertools::join;

assert_eq!(join(&[1, 2, 3], ", "), "1, 2, 3");