随机在数组中抽取两个不重复的数（收集了3种方法都挺不错的）

最新推荐文章于 2021-02-25 06:55:54 发布

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本文介绍了使用Java编程语言从数组中随机抽取不重复元素的三种方法，包括直接交换、ArrayList遍历去重以及HashMap辅助抽样。通过示例代码详细展示了每种方法的实现过程。

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public class FindStudent {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		String[] students = { “嘻嘻”，“哈哈”，“呵呵”“嘤嘤”};
		String[] speakers = new String[2];
		Random random = new Random();
		int n = students.length;

		for (int i = 0; i < 2; i++) {
			int num = random.nextInt(n);
			speakers[i] = students[num];
			students[num] = students[n - 1];
			n--;
			
		}
		
		for (int i=0;i<2;i++) {
			System.out.print(speakers[i]+ " "); 
	}

public class FindStudent {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

	String[] students = { “嘻嘻”，“哈哈”，“呵呵”“嘤嘤”

};List<String> speakers = new ArrayList<String>();Random random = new Random();int num = random.nextInt(students.length);int i = 0;while (i < 2) {String tmp = students[num];if (speakers.contains(tmp))continue;elsespeakers.add(tmp);i++;}System.out.println(speakers);

}
}

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class FindStudent {

public static void main(String[] args) {
// TODO 自动生成的方法存根
//从list中随机抽取元素
List list = new ArrayList();
List listNew = new ArrayList();
list.add(1);
list.add(2);
list.add(3);
list.add(4);
list.add(5);
listNew = createRandomList(list,3);
//从数组中随机抽取元素
int[] arr = {1,2,3,4,5};
int[] arrNew;
arrNew = createRandomArray(arr,3);
}

private static int[] createRandomArray(int[] arr, int n) {
// TODO Auto-generated method stub
Map map = new HashMap();
int[] arrNew = new int[n];
if(arr.length<=n){
return arr;
}else{
int count = 0;//新数组下标计数
while(map.size()<n){
int random = (int) (Math.random() * arr.length);
if (!map.containsKey(random)) {
map.put(random, "");
System.out.println(random+"==========="+arr[random]);
arrNew[count++] = arr[random];
}
}
return arrNew;
}
}
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;
}

}
}