js中的数组的操作遍历等

阳光穿透心脏的1/2处 2022-07-13 23:26 99阅读 0赞

<!DOCTYPE html>
    <html>
    <head lang="en">
        <meta charset="UTF-8">
        <title></title>
    </head>
    <body>
    <script>
    //-------------------数组的定义-----------------------
                    //定义1（字面量定义）
                    var array1 = [1,2,3];
                    var array2 = [];
                    console.log(typeof array1);
                    console.log(array1);
    
    
                    //定义2（对象创建）
                    var arr1 = new Array(); //空数组
                    var arr2 = new Array("关羽","张飞","刘备");
                    var arr3 = new Array(1,2,3);
                    var arr3 = new Array(3);
    //                console.log(arr1);
    //                console.log(arr2);
    //                console.log(arr3);
    
    //---------------------------数组的操作------------------------------
                    var arr = ["刘备","关羽","张飞"];
    
                    //数组长度
                    //    console.log(arr);
                    //    console.log(arr.length);
    
                    //通过索引值获取元素。
                    console.log(arr[0]);
                    console.log(arr[1]);
                    console.log(arr[2]);
                    console.log(arr[1222]);
    
                    //通过索引值，给元素赋值
                    arr[0] = "韩信";
                    arr[1] = "萧何";
                    arr[2] = "张良";
    
                    console.log(arr[0]);
                    console.log(arr[1]);
                    console.log(arr[2]);
    
    
    //--------------------数组的遍历---------------------------------
                var arr = ["关羽","张飞","赵云","马超","黄忠"];
    
                //遍历数组就是循环（获取）数组中的每一项
                for(var i=0;i<arr.length;i++){
                    //代表的是数组中的每一个元素；
                //        arr[i]
                    console.log(arr[i]);
                }
    
    </script>
    </body>
    </html>