javascript数组（array）的常用方法（shift/unshift/pop/push/concat/splice/reverse/sort/slice/join）

数组array

今天简单的介绍一下array对象的常用方法（shift/unshift/pop/push/concat/splice/reverse/sort/slice/join）在这就不多说直接撸代码

1.获取数组的长度 length

2.删除数组的第一个元素 shift

3.删除数组的最后一个元素 pop

4.删除或替换数组中的值,返回删除的值 splice 

5. 在数组前添加元素,返回数组长度 unshift

6.在数组后添加元素,返回数组长度 push

7.将数组反续 reverse

8.按指定的参数排序 sort

9.连接两个或更多的数组，并返回拼接结果（独立的新数组） concat

10.数组截取，返回一个截取结果（独立的新数组） slice

11.将数组元素组成一个字符串   join

12.将数组转化成字符串 toString 

13.将数组转换为本地数组 toLocaleString

代码示例如下：

（实例中arr数组是一直随着每条命令修改而变化的不是固定一个值的）

<script type="text/javascript">
var arr=["a","b","c","d","e","f","g","h","i","j"];
// 数组的长度 length
   var arrLength=arr.length;  // arrLength=10


//删除数组元素 shift pop  ==>  splice(替换删除)


   // shift 删除数组的第一个元素，返回删除的值
      var arrShift=arr.shift();   // arr=["b","c","d","e","f","g","h","i","j"]
                                  // arrShift="a"

   // pop 删除数组的最后一个元素，返回删除的值
      var arrPop=arr.pop();  // arr=["b","c","d","e","f","g","h","i"]
                             // arrPop="j"

   // splice 删除或替换数组中的值,返回删除的值  splice(开始值下标,个数,替换的值,替换的值.....)
      var arrSplice=arr.splice(2,2)   // arr=["b","c","f","g","h","i"]
                                     // arrSplice=["d","e"]


      var arrSpliceTwo=arr.splice(0,3,"a","b","c")   // arr=["a","b","c","g","h","i"]
                                                            // arrSpliceTwo=["b","c","f"]


// 添加数组元素 unshift push 

   // 在数组前添加元素,返回数组长度
      var arrUnshift=arr.unshift("1");   // arr=["1","a","b","c","g","h","i"]
                                         // arrUnshift=7


   // 在数组后添加元素,返回数组长度
      var arrPush=arr.push("j");   // arr=["1","a","b","c","g","h","i","j"]
                                   // arrPush=8

// 给数组内部元素排序 reverse sort


   // 将数组反续 reverse
      var arrReverse=arr.reverse();   // arr=["j","i","h","g","c","b","a","1"]
                                      // arrReverse=["j","i","h","g","c","b","a","1"]


   // 按指定的参数排序 sort 可以传递函数进行计算
      var arrSort=arr.sort();   // arr=["1","a","b","c","g","h","i","j"]
                                // arrSort=["1","a","b","c","g","h","i","j"]


//连接两个或更多的数组，并返回结果 concat
   var arrOne=[2,3,4];
   var arrTwo=[6,7,8];
   var arrS=["a","b","c"];
   var arrArr=arrOne.concat(arrTwo);   //arrArr=[2, 3, 4, 6, 7, 8]
   var arrArrT=arrOne.concat(arrTwo,arrS);   //arrArrT=[2, 3, 4, 6, 7, 8, "a", "b", "c"]
   var arrArrS=arrOne.concat("5","6","7");   //arrArrS=[2, 3, 4, "5", "6", "7"]
   //当concat()的传值为空时，则返回一个和原数组相同的独立的新数组，此时新数组和原数组没有任何关联引用关系
   //我们可以用来数组复制
   var arrClone=arrS.concat();//此时arrClone为一个新数组无论arrS元素如何变动arrClone都不会变


// 数组截取 slice slice(start,end) 不包括end值
   var arrSlice=arr.slice(2,5);   // arr=["1","a","b","c","g","h","i","j"]
                                  // arrSlice= ["b", "c", "g"]
    //当slice()的传值为空时，则返回一个和原数组相同的独立的新数组，此时新数组和原数组没有任何关联引用关系

var arrClone1=arr.slice();//此时arrClone1为一个新数组无论arr元素如何变动arrClone1都不会变
// 数组变为字符串 join toString toLocaleString 
    // 将数组元素组成一个字符串  以（）中的值为分割符，默认为","     
    arr=["1","a","b","c","g","h","i","j"];   
    var arrJoin=arr.join(""); // arrJoin= 1abcghij    
    var arrJoinTwo=arr.join(); // arrJoinTwo=1,a,b,c,g,h,i,j     
    var arrJoinS=arr.join("-"); // arrJoinS=1-a-b-c-g-h-i-j//将数组转化成字符串    
    var arrString=arr.toString(); // arrString= 1,a,b,c,g,h,i,j
   //将数组转换为本地数组   
    var arrLocaleString=arr.toLocaleString(); // arrString= 1,a,b,c,g,h,i,j
</script>