Array操作

1.创建数组

var  arr = [];
var  arr = new Array();
var arr =new Array("1","2","3");

2.forEach遍历

var fn = new Array("1","2","3");
fn.forEach(function(item,index){
    console.log(item,index);
});
//1 ，0
// 2， 1
//3 ，2

3.for循环

var fn = new Array("1","2","3");
for(let i = 0; i< fn.length; i++){
       console.log(fn[i])
};

4.for of 循环,会把数组中值的类型直接输出

var fn = new Array("a","b","c");
for(let i  of fn){
    console.log(i);
};
//a
//b
//c

5.for in 遍历会将数组的下标输出出来

var fn = new Array("a","b","c");
for(let i  in fn){
    console.log(i);
};
//0
//1
//2

6.显示源代码toSource()此方法只支持火狐，其他浏览器暂不支持。

function Body(name,age,height){
    this.name=name;
    this.age= age;
    this.height= height;
};
var newbody = new Body("小明","18","178cm");
var newbodyFunction = newbody.toSource();
console.log(newbodyFunction)

7.map遍历

var fn = new Array("a","b","c");
fn.map(function(x,y){
        console.log(x,y);
});
//a 0
//b 1
//c 2

遍历开方返回新数组，原数组不变
var fn = new Array("4","16","25");
 var fnn = fn.map(Math.sqrt);
 console.log(fnn);
//[2, 4, 5]；

Array操作

推荐阅读更多精彩内容