use std::collections::HashMap;
fn main() {
 let mut scores = HashMap::new();
 //需要保持<key,value>类型一致
 scores.insert("Sunface", 98);
 scores.insert("Daniel", 95);
 scores.insert("Ashley", 69);
 scores.insert("Katie", 58);
 // get 返回一个 Option<&V> 枚举值
 let score = scores.get("Sunface");
 assert_eq!(score, Some(&98));
 if scores.contains_key("Daniel") {
 // 索引返回一个值 V
 let score = scores["Daniel"];
 assert_eq!(score, 95);
 scores.remove("Daniel");
 }
 assert_eq!(scores.len(), 3);
 for (name, score) in scores {
 println!("The score of {} is {}", name, score)
 }
}

use std::collections::HashMap;
fn main() {
 let teams = [
 ("Chinese Team", 100),
 ("American Team", 10),
 ("France Team", 50),
 ];
 let mut teams_map1 = HashMap::new();
 for team in &teams {
 teams_map1.insert(team.0, team.1);
 }
 // 使用两种方法实现 team_map2
 // 提示:其中一种方法是使用 `collect` 方法
 let teams_map2:HashMap<_,_>=teams.into_iter().collect();
 assert_eq!(teams_map1, teams_map2);
 println!("Success!")
}

use std::collections::HashMap;
fn main() {
 let teams = [
 ("Chinese Team", 100),
 ("American Team", 10),
 ("France Team", 50),
 ];
 let mut teams_map1 = HashMap::new();
 for team in &teams {
 teams_map1.insert(team.0, team.1);
 }
 // 使用两种方法实现 team_map2
 // 提示:其中一种方法是使用 `collect` 方法
 let teams_map2=teams_map1.clone();
 assert_eq!(teams_map1, teams_map2);
 println!("Success!")
}

// 填空
use std::collections::HashMap;
fn main() {
 // 编译器可以根据后续的使用情况帮我自动推断出 HashMap 的类型,当然你也可以显式地标注类型:HashMap<&str, u8>
 let mut player_stats = HashMap::new();
 // 查询指定的 key, 若不存在时,则插入新的 kv 值
 player_stats.entry("health").or_insert(100);
 assert_eq!(player_stats["health"], 100);
 // 通过函数来返回新的值
 player_stats.entry("health").or_insert_with(random_stat_buff);
 assert_eq!(player_stats["health"], 100);
 let health = player_stats.entry("health").or_insert(50);
 assert_eq!(*health, 100);
 *health -= 50;
 assert_eq!(*health, 50);
 println!("Success!")
}
fn random_stat_buff() -> u8 {
 // 为了简单,我们没有使用随机,而是返回一个固定的值
 42
}

// 修复错误
// 提示: `derive` 是实现一些常用特征的好办法
use std::collections::HashMap;
#[derive(Eq,Hash,PartialEq,Debug)]
struct Viking {
 name: String,
 country: String,
}
impl Viking {
 fn new(name: &str, country: &str) -> Viking {
 Viking {
 name: name.to_string(),
 country: country.to_string(),
 }
 }
}
fn main() {
 // 使用 HashMap 来存储 viking 的生命值
 let vikings = HashMap::from([
 (Viking::new("Einar", "Norway"), 25),
 (Viking::new("Olaf", "Denmark"), 24),
 (Viking::new("Harald", "Iceland"), 12),
 ]);
 // 使用 derive 的方式来打印 viking 的当前状态
 for (viking, health) in &vikings {
 println!("{:?} has {} hp", viking, health);
 }
}

// 修复错误,尽可能少的去修改代码
// 不要移除任何代码行!
use std::collections::HashMap;
fn main() {
 let v1 = 10;
 let mut m1 = HashMap::new();
 m1.insert(v1, v1);
 println!("v1 is still usable after inserting to hashmap : {}", v1);
 let v2 = "hello".to_string();
 let mut m2 = HashMap::new();
 // 所有权在这里发生了转移
 m2.insert(v2.clone(), v1);
 assert_eq!(v2, "hello");
 println!("Success!")
}

let mut teams_map1 = HashMap::new();
for team in &teams {
 teams_map1.insert(team.0, team.1);
}
// IMPLEMENT team_map2 in two ways
// Tips: one of the approaches is to use `collect` method
// let teams_map2 : HashMap<&str, i32> = teams.into();
// let teams_map2 : HashMap<&str, i32> = teams.into_iter().collect();
let teams_map2 : HashMap<&str, i32> = HashMap::from(teams);
assert_eq!(teams_map1, teams_map2);
println!("Success!");

fn random_stat_buff() -> u8 {
 // 为了简单,我们没有使用随机,而是返回一个固定的值
 42
}