自己記錄一下,方便以後使用也好,還是方便其他朋友都可以的,代碼直接複製粘貼就能跑起來。那些註釋掉的代碼可以刪掉。
我是懶得刪,就直接貼上來了。
代碼的意思是:
1. 一個新的集合list1,裏面有26個對象(個數可以自己定義);
2. 從26個對象裏,隨機抽取,指定個數的,不重複的對象出來;
3. 然後從list1裏面刪除掉已經抽取出來的對象;
4. 保留剩餘的,未被抽取出來的對象;
package test;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
public class TestRandom {
public static void main(String[] args) {
List list = getArraylist();
System.out.println("list1:"+list);
List list3 = list;
System.out.println(list.get(list.size()-1));//list集合最後一位
// List list2 = winnerPrizeUser(5,list3);
List list2 = winnerPrizeUser222(5,list3);
/*if(list3.containsAll(list2)){
list3.removeAll(list2);//抽一次,就刪除抽中的。
}*/
for(int i=0;i<list2.size();i++){
if(list3.contains(list2.get(i))){
list3.remove(list2.get(i));
}
}
System.out.println("list2:"+list2);
System.out.println("list3:"+list3);
// System.out.println("list3:"+list3);
/*Random random = new Random();
int a = random.nextInt(list.size());
System.out.println(a);
System.out.println(list.get(a));
System.out.println("======================================");
boolean[] bool = new boolean[list.size()];
int randInt = 0;
List list2 = new ArrayList();
for(int i=0;i<5;i++){
do {
randInt = random.nextInt(list.size());
}while(bool[randInt]);
bool[randInt] = true;
System.out.println(list.get(randInt));
list2.add(list.get(randInt));
}
Collections.sort(list2);
System.out.println("=====================================");
System.out.println(list2);*/
}
public static List winnerPrizeUser222(int prizeNum,List userSizeList){
int user_size = userSizeList.size();
Random random = new Random();
boolean[] bool = new boolean[user_size];
int randInt = 0;
List winner_users = new ArrayList();
for(int i=0;i<prizeNum;i++){
do {
randInt = random.nextInt(user_size);
}while(bool[randInt]);
bool[randInt] = true;
winner_users.add(userSizeList.get(randInt));
}
return winner_users;
}
public static List winnerPrizeUser(int prizeNum,List userSizeList){
int size = userSizeList.size();
Random random = new Random();
int a = random.nextInt(size);
/* System.out.println(a);
System.out.println(userSizeList.get(a));
System.out.println("======================================");*/
boolean[] bool = new boolean[size];
int randInt = 0;
List list2 = new ArrayList();
for(int i=0;i<prizeNum;i++){
do {
randInt = random.nextInt(size);
}while(bool[randInt]);
bool[randInt] = true;
// System.out.println(userSizeList.get(randInt));
list2.add(userSizeList.get(randInt));
}
Collections.sort(list2);
/*System.out.println("=====================================");
System.out.println(list2);*/
return list2;
}
public static List getArraylist(){
List list = new ArrayList();//下標以0開始
list.add("AA");
list.add("BB");
list.add("DD");
list.add("CC");
list.add("GG");
list.add("FF");
list.add("QQ");
list.add("WW");
list.add("EE");
list.add("RR");
list.add("TT");
list.add("YY");
list.add("UU");
list.add("II");
list.add("OO");
list.add("PP");
list.add("SS");
list.add("HH");
list.add("JJ");
list.add("KK");
list.add("LL");
list.add("ZZ");
list.add("XX");
list.add("VV");
list.add("NN");
list.add("MM");
return list;
}
}