javascript----数组的方法

 1---join()
 //1----->join()方法将数组中所有元素都转化《《字符串》》
     //并连接在一起
     //array.join()方法是string.split()方法逆向操作

     var a=[1,2,3];//创建一个包含三个元素的素组
     var c=["多多","梦曦","洛瑶"];
     console.log(a.join())
     console.log(a.join(" "))
     console.log(a.join(""))

 //2---->reverse()  将数组中元素颠倒顺序，返回逆序的数组
     //下面的代码使用reverse 和join()方法生成字符串
     var myarray=["狗狗","毛毛","多多","阿黄"]
     console.log(myarray.reverse());
     //顺讯反转 ，以字符串输出结果
     console.log(myarray.reverse().join())

  //3---->array.sort()方法将数组中元素排序
     //并返回排序后的数组，
     //数组元素以字母表

     var myArray=["dudu","xiaoxiao","diandian","bibi"];

     console.log(myArray.sort())
     console.log(myArray.sort().join())
     var MyArray=[3,2,1,5,6];
     console.log(MyArray.sort())
     var MyArray1=[111,44,66,77];
     MyArray1.sort();
     MyArray1.sort(function(a,b){
         return a-b;

     });
     MyArray1.sort(function(a,b){
         return b-a;
     });

   //4----->concat() 连接数组，对数组合并
     var MyArray2=[32,23,14,15,6];
     var MyArray3=["花花","梦瑶","叶子","欣欣"]
     mm= MyArray2.concat(MyArray3,myArray)
     console.log(mm)
     c= MyArray2.concat(4,5,66)
     console.log(c)
     m=MyArray3.concat(["gouzi","小粒","多多"])
     console.log(m)

 //5----->Arry.slice()方法返回指定数组的一个片段或子数组
     //两个参数分别指定了开始的结束位置
     MyArray4=["伤心地","梦瑶池","滴滴哒哒","小狐狸"]
     d=MyArray4.slice(1,2).concat(MyArray3)
     console.log(d)

     //6----splice()方法是指在数组中插入或删除元素通用方法
     //splice和slice拥有非常相似的名字
     MyArray5=["香蕉","苹果","梨","花生","地瓜"]
     console.log(MyArray5.splice(3))
     console.log(MyArray5.splice(1,3))

     //7---push()和pop()
     //---push()在末尾添加元素，并返回新的<<长度>>
     //---pop()删除末尾的最后一个元素
     console.log("push方法是添加字符，返回一个新的长度")
     MyArray6=["狗儿","猫猫","小猪","小白"];
     console.log(MyArray6.push("小青蛇"))
     MyArray7=["狗儿","猫猫","小猪","小白"];
     console.log("pop（）删除末尾，返回的是删除的元素")
     console.log(MyArray7.pop())

  //8---->unshift() 和shift()
     /***
      * unshift()在头部添加一个或多个元素，最后返回新的长度
      * shift()删除数组第一个元素并将其返回
      *
      */
     MyArray8=["农夫三泉","怡宝","康师傅","和其正","金银花"]
     console.log(MyArray8.unshift("雪碧","小花咪"))
     MyArray8=["农夫三泉","怡宝","康师傅","和其正","金银花"]
     console.log(MyArray8.shift())

     //---->forEach()方法从头至尾遍历数组