1 List<Integer> list = new ArrayList<Integer>();
2
3 Random r = new Random();
4 int j;
5 for( int i = 0; i < 10; i++ ) {
6 j = r.nextInt(100);//小于100的随机数
7 list.add(j);//向list集合添加随机数
8 }
-
- 增加循环遍历
1 for( Integer i : list) {
2 System.out.print(i+"\t");
3 }
-
- 迭代器迭代
1 Iterator<Integer> iterator = list.iterator();
2 while( iterator.hasNext()) {
3 System.out.print(iterator.next()+"\t");
4 }
1 Set<String> set = new TreeSet<String>();
2
3 String []strings = {"北京","广州","昆明","大理","成都"};5 for( int i = 0; i < strings.length; i++ ) {
6 set.add(strings[i]);
7 }
-
- 增加循环遍历
1 for(String s : set ) {
2 System.out.print(s+"\t");
3 }
-
- 迭代器迭代
1 Iterator<String> iterator = set.iterator();
2 while(iterator.hasNext()) {
3 System.out.print(iterator.next()+"\t");
4 }
1 Map<Integer, String > map = new HashMap<Integer, String>();
2 int []key = {0,1,2,3,4};
3 String []name = {"lihua","popo","kejo","nace","jake"};
4
5 for(int i = 0; i < key.length; i++ ) {
6 map.put(key[i], name[i]);
7 }
-
- 增强循环遍历
1 for(Integer i : map.keySet()) {
2 String outName = map.get(i);
3 System.out.print("["+i + " "+ outName+"] ");
4 }
-
- 迭代器遍历
1 System.out.println("迭代器遍历");
2 Iterator<Map.Entry<Integer, String>> iterator = map.entrySet().iterator();
3 while( iterator.hasNext()) {
4 System.out.print(iterator.next());
5 }