List list = new ArrayList(); Random random = new java.util.Random(); while (list.size() < 15) { Integer ii = new Integer(random.nextInt(15)); if (!list.contains(ii)) { list.add(ii); } System.out.println( "*******" + list.toString()); }
import java.util.ArrayList; import java.util.List; import java.util.Random;public class test2 { public test2() { List<Integer> list = new ArrayList<Integer>(); List<Integer> list2 = new ArrayList<Integer>(); for (int i = 1; i <= 35; i++) { list.add(i); } Random random = new java.util.Random(); while (list2.size() < 7) { Integer ii = new Integer(random.nextInt(list.size()));
if (!list2.contains(list.get(ii))){ list2.add(list.get(ii)); } } for (int i:list2){ System.out.print(i+"\t"); } } public static void main(String[] args) { new test2(); } }
楼主的要求和“洗牌算法”很类似,就是在一副牌中随机抽几张出来,肯定是不重复的 int[] data = new int[50]; for(int i=0; i<data.length; i++) data[i] = i + 1;int lastIndex = data.length; for(int i=0; i<10; i++){ int p = 得到 0~lastIndex 之间的随机数 访问 data[p]; 将 data[p] 和 data[lastIndex] 交换 lastIndex--; }
Random random = new java.util.Random(); while (list.size() < 15) {
Integer ii = new Integer(random.nextInt(15));
if (!list.contains(ii)) {
list.add(ii);
}
System.out.println( "*******" + list.toString());
}
http://blog.csdn.net/chosen0ne/archive/2011/01/11/6129315.aspx
随机访问一个数组的元素,楼主可以看一下
import java.util.ArrayList;
import java.util.List;
import java.util.Random;public class test2 {
public test2() {
List<Integer> list = new ArrayList<Integer>();
List<Integer> list2 = new ArrayList<Integer>(); for (int i = 1; i <= 35; i++) {
list.add(i);
} Random random = new java.util.Random(); while (list2.size() < 7) {
Integer ii = new Integer(random.nextInt(list.size()));
if (!list2.contains(list.get(ii))){
list2.add(list.get(ii));
}
}
for (int i:list2){
System.out.print(i+"\t");
}
} public static void main(String[] args) {
new test2();
}
}
int[] data = new int[50];
for(int i=0; i<data.length; i++) data[i] = i + 1;int lastIndex = data.length;
for(int i=0; i<10; i++){
int p = 得到 0~lastIndex 之间的随机数
访问 data[p];
将 data[p] 和 data[lastIndex] 交换
lastIndex--;
}