conditional_trunc.rs

fn main() {
    let s = "...".to_string();
    let a = vec!["abc","abcde","abcdefgh","abcdefghijkl","abcdefghijklmnop"]
        .into_iter()
        .map(String::from)
        .map(|mut string| 
             if string.len() > 5 { string.truncate(5); [string, s.to_string()].join("") } 
             else {string.truncate(5); string})
        .collect::<Vec<String>>();
    println!("{:?}",a)
}