3 use std::collections::HashMap;
5 fn process_or_insert_default(map: &mut HashMap<usize, String>, key: usize) {
6 match map.get_mut(&key) {
11 map.insert(key, "".to_string());
17 assert_eq!(x, "Hello, world");
21 let map = &mut HashMap::new();
22 map.insert(22, format!("Hello, world"));
23 map.insert(44, format!("Goodbye, world"));
24 process_or_insert_default(map, 22);
25 process_or_insert_default(map, 66);
26 assert_eq!(map[&66], "");