rust - Create a vector from iterating hashmap -

what optional way in rust iterate hashmap , collect result vec? attempt far:

use std::collections::hashmap;  struct user {     reference: string,     email: string }  fn main() {      let mut users: hashmap<string, user> = hashmap::new();     users.insert("first".to_string(), user { reference: "ref1".to_string(), email: "test@test.com".to_string() });     users.insert("second".to_string(), user { reference: "ref2".to_string(), email: "test1@test.com".to_string() });     users.insert("third".to_string(), user { reference: "ref3".to_string(), email: "test3@test.com".to_string() });      //this failed attempt     let user_refs: vec<string> = users.iter().map(|(_, user)| &user.reference.clone()).collect();  } 

throws error

src/main.rs:15:85: 15:94 error: trait `core::iter::fromiterator<&collections::string::string>` not implemented type `collections::vec::vec<collections::string::string>` [e0277] src/main.rs:15  let user_refs: vec<string> = users.iter().map(|(_, user)| &user.reference.clone()).collect();                                                                                                    ^~~~~~~~~ src/main.rs:15:85: 15:94 note: collection of type `collections::vec::vec<collections::string::string>` cannot built iterator on elements of type `&collections::string::string` src/main.rs:15  let user_refs: vec<string> = users.iter().map(|(_, user)| &user.reference.clone()).collect();                                                                                                    ^~~~~~~~~ error: aborting due previous error 

your resulting vec needs own strings, remove & before user.reference.clone().

playground url: https://play.rust-lang.org/?gist=6a6b50ebf589fcce1dbf&version=nightly

gist url: https://gist.github.com/6a6b50ebf589fcce1dbf