我就废话不多说了,大家还是直接看代码吧~
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/**
* 从list中随机抽取元素
*
* @param list
* @param n
* @return void
* @throws
* @Title: createRandomList
* @Description: TODO
*/
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, "" );
System.out.println(random + "===========" + list.get(random));
listNew.add(list.get(random));
}
}
return listNew;
}
}
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扩展:
截取list
list.subList(0, 2);
补充知识:java list随机打乱顺序
通过 Collections.shuffle(list)来打乱顺序
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List<String> list = new ArrayList<String>();
list.add( "mjb" );
list.add( "hh" );
list.add( "lw" );
list.add( "pqj" );
list.add( "hj" );
System.out.println( "前:" );
for ( int i= 0 ;i<list.size();i++){
System.out.print(list.get(i)+ " " );
}
System.out.println( "" );
System.out.println( "后:" );
Collections.shuffle(list);
for ( int i= 0 ;i<list.size();i++){
System.out.print(list.get(i)+ " " );
}
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以上这篇java list随机抽取元素的案例就是小编分享给大家的全部内容了,希望能给大家一个参考,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/u013939884/article/details/72364761