• JavaScript数组


     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

     

    低于ie8建议自己封装一个indexOf查找的方法

    <!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 type="text/javascript">
            /*//创建一个保存颜色的数组
            var colors=new Array(3);
            colors[0]="#f00";
            colors[1]="#0f0";
            colors[2]="#00f";
            console.log(colors);
            var nums=new Array(1,3,6,9);
            //console.log(nums);
            var cols=["red","yellow","green"];
            //console.log(cols);
            var infos=[6,"marry",true,{email:"marry@sohu.com"}];
            //console.log(infos);
            console.log(cols[1]);    //读取cols这个数组中索引为1的值*/
            var arr=["a","b","c","d"];
            // console.log(arr.length);    //4
            // arr.length=2;
            // arr[99]="z";
            // console.log(arr.length);    // 100
            //数组的遍历
            for(var i=0;i<arr.length;i++){
                console.log(arr[i]);
            }
        </script>
    </body>
    </html> 
    <!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 type="text/javascript">
            //push
            var colors=new Array("red","green");
            var len=colors.push("blue","yellow","black");
            console.log(len);
            //unshift
            var nums=[2,7,8,6];
            var size=nums.unshift(99,66);
            console.log(nums);
            //pop
            var n=nums.pop();
            console.log(nums);
            //shift
            var m=colors.shift();
            console.log(colors);
        </script>
    </body>
    </html>
    <!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 type="text/javascript">
            //join
            var nums=[2,4,5];
            var str=nums.join();    //2,4,5
            var words=["border","left","color"];
            //border-left-color
            var wordstr=words.join("-");
            console.log(wordstr);
            //reverse
            nums.reverse();
            console.log(nums);
            var strs=["a","b","c","d"];
            //返回dcba这个字符串
            var newstr=strs.reverse().join("");
            console.log(newstr); 
            //29,5,24,17,32
            var arr=[9,23,15,-99,88,12,-2];
            //降序
            /*arr.sort(function(a,b){
                return b-a
            });*/
            //升序
            arr.sort(function(a,b){
                return a-b
            })
            console.log(arr);
        </script>
    </body>
    </html>
    <!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 type="text/javascript">
            var arr1=["a","b","c"],
                arr2=["d","e",1,3],
                arr3;
            //concat
            arr3=arr1.concat(arr2,["m",99,8]);
            console.log(arr3);
            //slice
            var colors=["red","green","blue","yellow","orange"];
            //var newColors=colors.slice(1,3);
            // var newColors2=colors.slice(2,4);
            var newColors3=colors.slice(-4,3);
            console.log(newColors3);
            //完成以下代码段,实现b数组对a数组的拷贝,方法越多越好
            var a=[1,"yes",3],
                b;
            //1、数组遍历,push
            /*b=new Array();
            for(var i=0;i<a.length;i++){
                b.push(a[i]);
            }*/
            //2、concat()
            b=[].concat(a);
            console.log(b);
            //3、slice();
            b=a.slice(0);
            console.log(b);
        </script>
    </body>
    </html>
    <!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 type="text/javascript">
            var arr=["a","b","c","d","e","f"];
            //删除
            //var delArr=arr.splice(2,0);
            // console.log(arr);
            // console.log(delArr);
            //插入
            //var insertArr=arr.splice(3,0,"m","n",88);
            // console.log(arr);
            // console.log(insertArr);
            //替换
            var replaceArr=arr.splice(1,2,"x","y","z");
            console.log(arr);
            console.log(replaceArr);
        </script>
    </body>
    </html>
    <!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 type="text/javascript">
            var nums=[1,7,5,7,8,1,6,9];
            //var pos=nums.indexOf(7,3);
            // var pos=nums.lastIndexOf(1);
            var pos=nums.lastIndexOf("7");
            console.log(pos);
            //封装一个方法实现indexOf的功能
            function ArrayIndexOf(arr,value){
                //检测value在arr中出现的位置
                for(var i=0;i<arr.length;i++){
                    if(arr[i]===value){
                        return i;
                    }
                }
                return -1;
            }
            var pos2=ArrayIndexOf(nums,8);
            console.log(pos2);
        </script>
    </body>
    </html>
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  • 原文地址:https://www.cnblogs.com/zengyu1234/p/15781450.html
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