java在ArraysList对象中查找最小值

Question

我是Java和Android开发的法语初学者。事实上，我试着做练习，但我被卡住了

我有一个对象（Players）的数组列表（playersList2），Players包含string（mFirstName）和int（mScore））

我做了一些收集，循环的尝试，我读了很多文档和论坛，但我没有找到一个解决方案，但我很确定这很容易

    Players players = new Players(mFirstname, mScore);

    mPreferences = getSharedPreferences(PREF_PLAYERS_LIST, MODE_PRIVATE);
    String fromJsonPlayersList = mPreferences.getString(PREF_PLAYERS_LIST, null);

    Gson gson = new Gson();
    ArrayList<Players> playersList2 = gson.fromJson(fromJsonPlayersList, new TypeToken<ArrayList<Players>>()
    {
    }.getType());

    /* find the weakiest players/

    if  //mscore is bigger than weakest players
    {//remove the weakest players and add this one
    }*/

我想在整个ArrayList中找到最小的mScore，以形成一个条件（如果当前的mScore>；最小玩家列表2将最脆弱的玩家列表2替换为当前玩家）

非常感谢

Answer 1

假设这是你的球员课程：

    public class Players {
    String mFirstName;
    int mScore;

    public Players(String mFirstName, int mScore){
        this.mFirstName = mFirstName;
        this.mScore = mScore;
    }
}

这将得到你的最低分数：

public static void main(String[] args) {

    ArrayList<Players> playersList2 = new ArrayList<>();

    for (int i = 0; i < 10; i++){
        Players player = new Players("name", i);
    }

    Players lowestScore = playersList2.get(0);

    for (Players p: playersList2) {
        if (p.mScore < lowestScore.mScore){
            lowestScore = p;
        }
    }

    System.out.println(lowestScore.mScore);
}

Answer 2

有多种方法可以做到这一点

在开始解决方案之前，让我们先来看看这里的Player类：

class Player {
    String firstName;
    int score;

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public int getScore() {
        return score;
    }

    public void setScore(int score) {
        this.score = score;
    }
}

一种方法是循环遍历ArrayList并找到得分最低的玩家，另一种方法是使用流API找到得分最低的玩家

解决方案1：我们在列表中循环查找得分最低的玩家

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

// .. add some players in the List players

Player weakestPlayer = null;
int minScore = Integer.MAX_VALUE;
for(Player player : players) {
    if(player.getScore() < minScore) {
        weakestPlayer = player;
    }
}

解决方案2： 在java中使用流API是一个有点复杂的解决方案

Player weakestPlayer = players
        .stream()
        .min(Comparator.comparing(Player::getScore))
        .orElseThrow(NoSuchElementException::new);

该解决方案使用Java Stream API查找得分最低的玩家。这里我们使用min（）方法来找到得分最低的玩家。min（）方法需要一个比较器来帮助它比较分数，并决定哪个玩家的分数最低。下面的代码行获取int的比较器

Comparator.comparing(Player::getScore)

如果列表为空，那么它将抛出一个错误，因为它无法找到最低分数的玩家

Answer 3

最简单的解决方案是使用简单的for循环，例如：

Players minScorePlayer = playersList2.get(0);
for (Players player: playersList2) {
   if (player.getScore() < minScorePlayer.getScore()) {
      minScorePlayer = player;
   }
}
//now minScorePlayer variable contains the reference to a player with the minimal score

附：本代码旨在为您提供总体思路。你可能需要根据自己的需要进行调整