如何从一个数组中得到一个随机数组？

Question

String[] s={"a","b","c","d"};//['a'],['b'],['c'],['d'],['a','b'],['a ','c'],['a','d'],['b','c'],['b','d'],['c','d'],['a ','b','c']...['a','b','c','d']

我想要这样的结果。依靠这个数组，我想在其中得到一个随机值。

Answer 1

您只需随机选择结果中是否使用字符串来表示数组中的每个字符串：

String[] s={"a","b","c","d"};
Random rand=new Random();
List<String> sList=new ArrayList<>();
for(String elem:s){
    if(rand.nextBoolean()){
        sList.add(elem);
    }
}
String[] result=sList.toArray(s);

或使用流：

String[] s={"a","b","c","d"};
Random rand=new Random();
String[] result=Arrays.stream(s).filter(unused->rand.nextBoolean()).toArray(String[]::new);