Rust HashMap详解及单词统计示例用法详解

let mut scores = HashMap::new();
scores.insert(String::from("Blue"), 10);
scores.insert(String::from("Yellow"), 60);

let teams = vec![String::from("Blue"), String::from("Yellow")];
let initial_scores = vec![10, 50];
let scores: HashMap<_, _> = teams.iter().zip(initial_scores.into_iter()).collect();

let field_name = String::from("Favorite color");
let field_value = String::from("Blue");
let mut map = HashMap::new();
map.insert(&field_name, &field_value);

let team_name = String::from("Blue");
let score = scores1.get(&team_name);
match score {
    None => println!("Team not exist"),
    Some(s) => println!("Score: {}", s),
}
for (k, v) in &scores1 {
    println!("{}: {}", k, v);
}

let mut scores11 = HashMap::new();
scores11.insert(String::from("Blue"), 10);
scores11.insert(String::from("Blue"), 20);
// 使用entry方法检查键是否存在，不存在时插入新值
scores11.entry(String::from("Yellow")).or_insert(50);
scores11.entry(String::from("Blue")).or_insert(50);

let text = "hello world wonderful world";
let mut map = HashMap::new();
for word in text.split_whitespace() {
    let count = map.entry(word).or_insert(0);
    *count += 1;
}
println!("{:#?}", map);