javaScript中处理数组中重复元素的办法

参考链接：http://blog.csdn.net/zhihua_w/article/details/52184289

   以下方法自己都已经进行简单测试并且通过，需要的朋友可以直接拷贝使用！🙂

   一、获取数组中相同元素的下标

/**
     * @param    needle       重复元素值
     * @param    elementArray   对应的元素数组
     * @returns {Array}  返回一个数组
     */
  var  testArr = ["1","6","3","2","4","1","3","2","3","4","5"];
 function searchKeys(needle, elementArray)
    {
        console.log("needle=>"+needle,"elementArray=>"+elementArray)
        var result = [];
        for (i in elementArray)
        {
            if (elementArray[i] == needle)
            {
                result.push(i);
            }
        }
        return result;
    }

    console.log(searchKeys("1",testArr));

   二、将数组中重复元素过滤掉重新返回一个新的数组

1、方法一：

var  testArr = ["1","6","3","2","4","1","3","2","3","4","5"];
    Array.prototype.method1 = function(){
        var arr = [];    //定义一个临时数组
        for(var i = 0; i < this.length; i++){    //循环遍历当前数组
            //判断当前数组下标为i的元素是否已经保存到临时数组
            //如果已保存，则跳过，否则将此元素保存到临时数组中
            if(arr.indexOf(this[i]) == -1){
                arr.push(this[i]);
            }
        }
        return arr;
    }

    document.write(testArr.method1())//这个调用方法，将结果显示出来

2、方法二：

   var  testArr = ["1","6","3","2","4","1","3","2","3","4","5"];

    Array.prototype.method2 = function(){
        var h = {};    //定义一个hash表
        var arr = [];  //定义一个临时数组

        for(var i = 0; i < this.length; i++){    //循环遍历当前数组
            //对元素进行判断，看是否已经存在表中，如果存在则跳过，否则存入临时数组
            if(!h[this[i]]){
                //存入hash表
                h[this[i]] = true;
                //把当前数组元素存入到临时数组中
                arr.push(this[i]);
            }
        }
        return arr;
    }
    document.write(testArr.method2())

3、方法三：

   var  testArr = ["1","6","3","2","4","1","3","2","3","4","5"];

    Array.prototype.method3 = function(){
        //直接定义结果数组
        var arr = [this[0]];
        for(var i = 1; i < this.length; i++){    //从数组第二项开始循环遍历此数组
            //对元素进行判断：
            //如果数组当前元素在此数组中第一次出现的位置不是i
            //那么我们可以判断第i项元素是重复的，否则直接存入结果数组
            if(this.indexOf(this[i]) == i){
                arr.push(this[i]);
            }
        }
        return arr;

    }

    document.write(testArr.method3())

3、方法四：将结果按照从小到大的顺序排列出来

  var  testArr = ["1","6","3","2","4","1","3","2","3","4","5"];

    Array.prototype.method4 = function() {
        //将数组进行排序
        this.sort();
        //定义结果数组
        var arr = [this[0]];
        for (var i = 1; i < this.length; i++) {    //从数组第二项开始循环遍历数组
            //判断相邻两个元素是否相等，如果相等说明数据重复，否则将元素写入结果数组
            if (this[i] !== arr[arr.length - 1]) {
                arr.push(this[i]);
            }
        }
        return arr;

    }
        document.write(testArr.method4());