java - hashset从数组Java中删除重复项

Question

我目前正在尝试让我的java程序不在打印输出中打印出重复的法律。该软件是随机挑选打印出 1 到 3 个定律，但我不想要重复的。我对java还是个新手，到目前为止只写了几个程序。这是迄今为止我写过的最复杂的一篇。

现在，如果软件发现重复项，我希望软件再次运行随机项，直到打印中没有重复项为止。有办法做到这一点吗？

/**
    *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]);

    }

Answer 1

思考这个问题的另一种方式是；您想以随机顺序选择值。这样，除非元素出现多次，否则您不会获得重复项。

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);