假如我有一个数组：
ArrayList<Integer> mArrayList = new ArrayList<Integer>();
mArrayList.add(0);
mArrayList.add(1);
mArrayList.add(2);
mArrayList.add(3);
我需要从中随机抽取2个数 不能重复抽取，我就会用这个方法
public void getValue(ArrayList<Integer> mArrayList){
Random mRandom = new Random();
int a = mRandom.nextInt(mArrayList.size());
int value = mArrayList.get(a);
System.out.println(value + "");
mArrayList.remove(a);
}
原理就是每抽取一次就删除已经抽取出来的值，这样获取到的值就不会重复了
完整代码：
package com.xiaoqiu.test; import java.util.ArrayList; import java.util.Random; public class Test { public static void main(String[] args) { ArrayList<Integer> mArrayList = new ArrayList<Integer>(); mArrayList.add(0); mArrayList.add(1); mArrayList.add(2); mArrayList.add(3); Test mTest = new Test(); mTest.getValue(mArrayList); mTest.getValue(mArrayList); } public void getValue(ArrayList<Integer> mArrayList){ Random mRandom = new Random(); int a = mRandom.nextInt(mArrayList.size()); int value = mArrayList.get(a); System.out.println(value + ""); mArrayList.remove(a); } } |
测试结果：
3
2
3
0
2
3
