Java教程

JavaScript数组

本文主要是介绍JavaScript数组，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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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