java - 从数组列表中选择多个/随机元素

Question

除了 one 元素外，我如何从数组列表中选择随机元素？ 这是我的数组列表:

ArrayList <String> provinces = new ArrayList();

Collections.addAll(
    provinces, 
    "New Brunswick", 
    "Saskatchewan", 
    "Ontario", 
    "Nova Scotia", 
    "Quebec", 
    "Alberta");

对于这个例子，我想随机选择其他元素，除了萨斯喀彻温省。

我试过:

 for(int i == provinces.get (0); i < provinces.get(1); i > provinces.get(2); i < provinces.get(5)) {

     int getPossibleAnswers = (int) Math.floor(Math.random()*i);               
     String displayPossibleAnswers = provinces.get(getPossibleAnswers);                
     outputAnswers.append(displayPossibleAnswers + "\n");
     }

显然，这段代码不起作用，我不知道该怎么做。 提前致谢!

Answer 1

构建所有索引值的列表，除了萨斯喀彻温省的索引，然后将其打乱。

List<String> provinces = Arrays.asList("New Brunswick", "Saskatchewan", "Ontario", "Nova Scotia", "Quebec", "Alberta");

List<Integer> indexes = new ArrayList<>();
for (int i = 0; i < provinces.size(); i++)
    if (! provinces.get(i).equals("Saskatchewan"))
        indexes.add(i);
Collections.shuffle(indexes);

StringBuilder outputAnswers = new StringBuilder();
for (int i : indexes)
    outputAnswers.append(provinces.get(i) + "\n");

System.out.print(outputAnswers);

示例输出

Nova Scotia
Quebec
Ontario
Alberta
New Brunswick