可以建立索引并包含两个值的Java数据结构

Question

尽管开发足球/足球应用程序，但是我需要一个可以索引并包含两个值的数据结构。如果还可以排序，那将是很好。这两个值是玩家名称及其评分（满分10分）。例如

（约翰·史密斯，9岁）。

HashMaps的问题在于，即使它将包含两个值，数据本身也不被索引。

谢谢

Answer 1

使用Map<String, Integer>

将玩家姓名与其值相关联的地图应该可以完成此任务：

// Initialize the player map
Map<String, Integer> players = new HashMap<>();
players.put("John", 2);
players.put("Paul", 8);
players.put("Andrew", 5);

// Print all players sorted by name
players.entrySet().stream()
       .sorted(Map.Entry.comparingByKey())
       .forEach(System.out::println);

// Print all players sorted by rating
players.entrySet().stream()
       .sorted(Map.Entry.comparingByValue())
       .forEach(System.out::println);

// Find a player by name and print their details
System.out.println(players.get("Paul"));

但是，无法通过索引访问映射条目。继续阅读。

使用List<Player>

或者，您可以定义一个代表玩家的类：

public class Player {

    private String name;
    private Integer rating;

    public Player(String name, Integer rating) {
        this.name = name;
        this.rating = rating;
    }

    // Getters, setters and toString() methods
}

然后您将具有以下内容：

// Initialize the player list
List<Player> players = new ArrayList<>();
players.add(new Player("John", 2));
players.add(new Player("Paul", 8));
players.add(new Player("Andrew", 5));

// Print all players sorted by name
players.stream()
       .sorted(Comparator.comparing(Player::getName))
       .forEach(System.out::println);

// Print all players sorted by rating
players.stream()
       .sorted(Comparator.comparing(Player::getRating))
       .forEach(System.out::println);

// Find a player by name and print their details
String filter = "Paul";
players.stream()
       .filter(player -> player.getName().equals(filter))
       .findFirst()
       .ifPresent(System.out::println);

// Find a player by index and print their details
System.out.println(players.get(0));

Answer 2

1. 定义自己的类，如下所示：

   class Player {
       String name;
       float rating;
       // Class methods
   }
   

2. 在主类中创建List个Player中的一个{}：

   List<Player> players = new ArrayList<>();
   

3. 使用自定义Comparator进行排序：

   Comparator<Player> comparator = new Comparator<Player>() {
       @Override
       public int compare(Player p1, Player p2) {
           //Sorting logic
       }
   };
   
   players.sort(comparator);