【Java】【5】List隨機取值

//shuffle 打亂順序 
Collections.shuffle(list);
//隨機抽取1個值
System.out.println(list.get(0));
//隨機抽取N個值
System.out.println(list.size() < N ? list : list.subList(0, N));

其他方案：

隨機抽取1個值

public static void main(String[] args) {
    List<String> list = Arrays.asList("a","b","c");
    int index = (int) (Math.random()* list.size());
    System.out.println(list.get(index));
}

隨機抽取N個值

private static List createRandomList(List list, int n) {
    // TODO Auto-generated method stub
    Map map = new HashMap();
    List listNew = new ArrayList();
    if (list.size() <= n) {
        return list;
    } else {
        while (map.size() < n) {
            int random = (int) (Math.random() * list.size());
            if (!map.containsKey(random)) {
                map.put(random, "");
                listNew.add(list.get(random));
            }
        }
        return listNew;
    }
}

參考博客：

1，java list隨機抽取元素 - 小小的博客 - CSDN博客

https://blog.csdn.net/u013939884/article/details/72364761

2，Java List隨機取值 - 只能永遠把艱辛的勞動看作是生命的必要;即使沒有收獲的指望,也能心平氣靜的繼續耕種. - CSDN博客

https://blog.csdn.net/amoscn/article/details/80066865