如何在 Java 中计算 ArrayList 中特定项目的数量

Question

因此，我最近决定使用 Java 编程重新创建“骰子 10,000”游戏，但在让某些规则起作用时遇到了一些问题。有 4 条规则我无法开始工作。

1) 任意数字中的 3 = 3 个骰子面值的 10 倍

2) 完全顺子 (1 - 6) = 3,000 分

3) 3 对 = 1,000 分

4) 3 个一 = 1,000 分

我只是不确定如何让这些工作......我相信我会使用集合，但我对集合以及如何使用它们以及它们包含哪些方法非常非常缺乏经验。没有一套我大概能猜出第二个，但最麻烦的是第一个、第三个和第四个。

//Andrew M
import java.util.*;
import java.io.*;
class Zilch
{

    public static Random r = new Random();
    public static ArrayList<Integer> diceList = new ArrayList<Integer>();
    public static int count = 0, humanScore = 0, compScore = 0, humanBank = 0, compBank = 0, lastMove = 0;
    public static ArrayList<Integer> diceKeep = new ArrayList<Integer>();
    public static boolean gameOn = true, x = true;
    //-----------------------------------------------------------------------------------
    public static void main(String[] args)
    {
        for (int j = 1; j <= 6; j++)
        {
            diceList.add(j);
            diceKeep.add(null);
        }
        do
        {
            do
            {
                x = true;
                for (int k = 0; k < diceKeep.size(); k++)
                {
                    if (diceKeep.get(k) != null)
                    {
                        System.out.println("Dice #" + (k + 1) + ": " + diceKeep.get(k) + "  -- kept.");
                    }
                }
                System.out.println();
                System.out.println();
                boolean b = true;
                for (int i = 0; i < diceList.size(); i++)
                {
                    if(diceList.get(i) != 0)
                    {
                        diceList.set(i, r.nextInt(6) + 1);
                        System.out.println("Dice #" + (i+1) + " is a " + diceList.get(i));
                    }
                }
                System.out.println();
                System.out.println("Select which dice to roll again... (Select one at a time, 1 - 6), then type \"go\" to complete your turn.");
                Scanner input = new Scanner(System.in);

                /*-----------UNNECCESARY CODE--------------*/
                    else
                    if (selection.equals("go"))
                    {
                        System.out.println();
                        System.out.println();
                        if (diceKeep.get(0) == 1)
                        {
                            humanBank = humanBank + 100;
                            lastMove = 100;
                        }
                        else
                        if (diceKeep.get(0) == 5)
                        {
                            humanBank = humanBank + 500;
                            lastMove = 500;
                        }

/*--------------I NEED THE RULES TO GO HERE---*/        

                        b = false;
                    }
                }
                while(b == true);
                //-----------------------------------------------------------------------
                if(gameOn == true)
                {
                    x = true;
                    //Place Score Card Here
                }
            }
            while (x == true);
        }
        while (1< 2); //Just here for testing purposes, for now
    }
}

对不起，我知道现在很多。希望你们能给我一些示例代码让我继续前进吗？非常感谢。

一切顺利

安德鲁

编辑：截至目前，我要到明天早上才能回复。我为缺乏反馈而道歉，但为时已晚。我明天会回来尝试和回复。

Answer 1

在下面，我添加一些评论。它打印数组列表中的数字计数。

import java.util.ArrayList;

public class Test {

    public static void main(String[] args) {
        int [] i = new int [7]; //  array starts with 0, so we can init our array with size 7 (0 to 6).
        ArrayList<Integer> arr = new ArrayList<Integer>();

        // there are 2 times "5"
        arr.add(5); 
        arr.add(5);

        //add some null
        arr.add(null);

        // there is 1 times "3"
        arr.add(3);

        // there is 1 times "6"
        arr.add(6);

        //add some null
        arr.add(null);

        System.out.println("numbers in arr: " + arr);

        for (Integer integer : arr) {
            if (integer!= null)
                i[integer]++; 
        }

        for (int c = 0 ;c<i.length ; c++){
            System.out.println("there are/is " + c + " ->" + i[c] + " times");
        }
    }
}

打印：

numbers in arr: [5, 5, null, 3, 6, null]
there are/is 0 ->0 times
there are/is 1 ->0 times 
there are/is 2 ->0 times 
there are/is 3 ->1 times 
there are/is 4 ->0 times 
there are/is 5 ->2 times 
there are/is 6 ->1 times