1 package org.hanqi.array; 2 3 import java.util.*; 4 5 public class Test1 { 6 7 public static void main(String[] args) { 8 9 // 创建List 10 //1.指明数据类型,不需要指定大小 11 // <>表示泛型 12 List<String>list = new ArrayList<String>(); 13 ArrayList<Object>list1 = new ArrayList<Object>(); 14 //添加 15 list.add("a"); 16 list.add("b"); 17 list.add("c"); 18 //长度 19 System.out.println("集合List的长度="+list.size()); 20 //取出 21 System.out.println("按索引0取出get(0)="+list.get(0)); 22 23 System.out.println("遍历方式1"); 24 //遍历 25 for(int i=0;i<list.size();i++) 26 { 27 System.out.print(list.get(i)); 28 } 29 30 System.out.println(); 31 32 System.out.println("遍历方式2"); 33 list.remove(0); 34 for(String s:list) 35 { 36 System.out.print(s); 37 } 38 System.out.println(); 39 40 System.out.println("遍历方式3:迭代器"); 41 //获取集合的迭代器,迭代器一开始是在集合的最上面 42 Iterator<String> it = list.iterator(); 43 //试探 44 while(it.hasNext()) 45 { 46 String t = it.next(); 47 if(t.equals("b")) 48 { 49 it.remove(); 50 } 51 System.out.println("迭代器="+t); 52 } 53 54 //移除 55 //list.clear(); //全部移除 56 57 System.out.println("集合List的长度="+list.size()); 58 //插入 59 list.add(0, "A"); 60 for(String s:list) 61 { 62 System.out.print(s); 63 } 64 //修改 65 list.set(1, "B"); 66 //list.set(2, "C"); 67 for(String s:list) 68 { 69 System.out.println(s); 70 } 71 System.out.println("B="+list.indexOf("b")); 72 } 73 }
运行结果为:
附思维导图: