04-JavaScript数组的应用

1.数组的基础应用

<script>
   //定义数组,
        var arr = [1,2,3];
        //获取数组中的第二项,
         var  str = arr[1];
        //给数组中的第三项赋值、
       arr[2]= 10;

        //获取数组的长度、
//        console.log(arr.length);
      // 正向遍历数组
        for(var i = 0;i<arr.length;i++){
            arr[i];
            console.log(arr[i])
        }
        //  反向遍历数组、
     for(var i = arr.length-1; i>=0;i-- ){
         arr[i];
         console.log(arr[i])
     }
</script>

Snip20170817_5.png

2.字符串分割

//将字符串数组用\或者其他符号分隔
        var array = ["aa","bb","cc","dd","ee","ff"];
        var str = array[0];
        var seperatpr = "|";
        for(var i = 1;i<array.length;i++){
            str  +=  seperatpr + array[i];
        }
        console.log(str); //aa|bb|cc|dd|ee|ff

3.将数组中的某项值去除，生成新的数组

<script>
   var array1 = [1,2,3,0,4,0,5,0,0,6,0,7,0,8,9]
        var newArray =[];
        for(var i = 0;i < array1.length; i++){
            if (array1[i]!== 0){
                newArray[newArray.length]= array1[i];
            }
        }
        console.log(newArray);//Array [ 1, 2, 3, 4, 5, 6, 7, 8, 9 ]
</script>

4.获取数组中每一个字符的长度,存储到一个新的数组中去

<script>
  var array2 = ["asd","","123e","qwer"];
        var NewArray = [];

        for(var i = 0 ;i < array2.length;i++){

            NewArray[NewArray.length] = array2[i].length;

        }
        console.log(NewArray); //Array [ 3, 0, 4, 4 ]
</script>