lovecoding
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VIP32


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        /**
         * Map() 类似于对象 键值对中的对象
         * 可以使用扩展运算符 for..of
         * size 返回键值对中的元素个数
         * set() 往集合中添加键值对
         * get() 获取集合中的键值
         * has() 查找Map集合中是否包含所要查找的属性 返回值为布尔值
         * clear() 清空集合中的所有值 
         * entries() 键值对
         * keys() 键值对中的下标
         * values() 键值对中的值
         * 
        */
       let s1 = new Map();
       console.log(s1,'s1');
       let s2 = new Map([
        ["name","Lucy"],
        ["age","18"],
        ["address","哈尔滨"]
       ]);
       console.log(s2,'s2');
       console.log(s2.size);
       s2.set("sex","女")
       console.log(s2);
       console.log(s2.get("name"));
       console.log(s2.has("age"));
       s2.clear();
       console.log(s2.clear());
       console.log(s2);

       var arr = [1,2,3,4,5,6];
       arr.map((ele,index)=>{
        console.log(ele,'值');
        console.log(index,'下标');
       })

       var arr2 = new Map();
       arr2.set("color","red");
       arr2.set("school","US");
       console.log(arr2);

       for(let a of arr2.entries()) {
        console.log(a,'entries');
       }
       for(let a of arr2.keys()) {
        console.log(a,'keys');
       }
       for(let a of arr2.values()) {
        console.log(a,'values');
       }

       console.log(arr2.keys().next().value)
       console.log(arr2.entries().next().value)
       console.log(arr2.values().next().value)

    </script>
</body>
</html>