package cn.test.logan.day06;

import java.util.HashMap;

public class HashMapDemo {
    public static void main(String[] args) {
        // 构建一个hashmap对象
        HashMap<String,String> map1 = new HashMap<>();
        
        // 添加元素
        map1.put("1", "Jack");
        map1.put("2", "Logan");
        map1.put("3", "Tom");
        map1.put("4", "Alice");
        
        // 获取元素
        String a = map1.get("2");
        System.out.println(a);
        
        // 获取长度
        int size = map1.size();
        System.out.println(size);
        
        // 从map1中移除元素
        String b = map1.remove("3");
        System.out.println(b);
        
        // 判断数据是否存在
        boolean c = map1.containsKey("3");
        System.out.println(c);
    }
}