用于从Java数组中删除重复项的哈希集

我目前正试图让我的java程序在打印时不打印出重复的定律。该软件是随机挑选打印出1至3条法律，但我不想重复。我对java还是一个新手，到目前为止只编写了几个程序。这是迄今为止我写过的最复杂的一篇

现在，我希望软件再次运行随机，如果它发现一个重复，直到没有重复的打印。有什么办法可以这样做吗

/**
    *Seeds is a random number to pick which if statement will be used. 
    * telling the software how many laws to use during its random 
    * generation process
    * 
    */
    Random seeds = new Random(); 
    seed = seeds.nextInt(3) + 1; 

    if (seed == 1){


        /**Beginning of random law selection for universe. Must find way 
         *Must find way to get rid of duplicate answers 
         */
        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            System.out.println("Law:" + Laws[index]);
    }

    else if (seed == 2) {

        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            int index2 = random.nextInt(Laws.length);
            System.out.println("Law:" + Laws[index] + "," + Laws[index2]);

    }

    else {

        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            int index2 = random.nextInt(Laws.length);
            int index3 = random.nextInt(Laws.length);
            System.out.println("Law: " + Laws[index] + "," + Laws[index2] + 
                    "," + Laws[index3]);

    }

---

另一种思考这个问题的方式是；您希望以随机顺序选择值。这样，除非元素多次出现，否则不会得到重复的元素

List<String> laws = Arrays.asList("Standard Physics", "Magic", "Mad Science", 
        "Psionics", "Substandard Physics","Exotic");
Collections.shuffle(laws);
// select as many as you need
List<String> lawsSelected = laws.subList(0, 3);

List laws=array.asList（“标准物理”、“魔法”、“疯狂科学”，
“灵能”、“次等物理”、“奇异”）；
收藏。洗牌（法律）；
//根据需要选择任意数量
List lawsSelected=laws.subList（0,3）；

思考这个问题的另一种方式是；您希望以随机顺序选择值。这样，除非元素多次出现，否则不会得到重复的元素

List<String> laws = Arrays.asList("Standard Physics", "Magic", "Mad Science", 
        "Psionics", "Substandard Physics","Exotic");
Collections.shuffle(laws);
// select as many as you need
List<String> lawsSelected = laws.subList(0, 3);

List laws=array.asList（“标准物理”、“魔法”、“疯狂科学”，
“灵能”、“次等物理”、“奇异”）；
收藏。洗牌（法律）；
//根据需要选择任意数量
List lawsSelected=laws.subList（0,3）；

这里有一种方法。你有3个if条件，所以取3个布尔变量，将一个与每个if关联，并在执行if时使其为真

Random seeds = new Random(); 
    seed = seeds.nextInt(3) + 1; 


boolean selected[] = new boolean[3];
selected[0] = selected[1] = selected[2] = false;//initially none of the if is executed

    if (seed == 1 && !selected[seed-1]){//checking if not previously selected and "seed-1" since array indexes are from 0 to n-1


        /**Beginning of random law selection for universe. Must find way 
         *Must find way to get rid of duplicate answers 
         */
        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            System.out.println("Law:" + Laws[index]);
            selected[seed-1] = true;
    }

    else if (seed == 2 && !selected[seed-1]) {

        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            int index2 = random.nextInt(Laws.length);
            System.out.println("Law:" + Laws[index] + "," + Laws[index2]);
            selected[seed-1] = true;
    }

    else if (!selected[seed-1]){

        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            int index2 = random.nextInt(Laws.length);
            int index3 = random.nextInt(Laws.length);
            System.out.println("Law: " + Laws[index] + "," + Laws[index2] + 
                    "," + Laws[index3]);
        selected[seed-1] = true;
    }

---

这里有一种方法。你有3个if条件，所以取3个布尔变量，将一个与每个if关联，并在执行if时使其为真

Random seeds = new Random(); 
    seed = seeds.nextInt(3) + 1; 


boolean selected[] = new boolean[3];
selected[0] = selected[1] = selected[2] = false;//initially none of the if is executed

    if (seed == 1 && !selected[seed-1]){//checking if not previously selected and "seed-1" since array indexes are from 0 to n-1


        /**Beginning of random law selection for universe. Must find way 
         *Must find way to get rid of duplicate answers 
         */
        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            System.out.println("Law:" + Laws[index]);
            selected[seed-1] = true;
    }

    else if (seed == 2 && !selected[seed-1]) {

        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            int index2 = random.nextInt(Laws.length);
            System.out.println("Law:" + Laws[index] + "," + Laws[index2]);
            selected[seed-1] = true;
    }

    else if (!selected[seed-1]){

        final String[] Laws = {"Standard Physics", "Magic", "Mad Science", 
            "Psionics", "Substandard Physics","Exotic"};
            Random random = new Random();
            int index = random.nextInt(Laws.length);
            int index2 = random.nextInt(Laws.length);
            int index3 = random.nextInt(Laws.length);
            System.out.println("Law: " + Laws[index] + "," + Laws[index2] + 
                    "," + Laws[index3]);
        selected[seed-1] = true;
    }

---

更少的代码行，更少的问题，相同字符串数组的3个声明不好，首先声明一次if else无块代码行，更少的问题，相同字符串数组的3个声明不好，首先声明一次if else块