數組去重的幾種方法

數組去重的幾種方法

• 數組去重1

    var ary1=[1,2,3,1,3,4,5,6,7];
    //ary.splice(0,3);//4,5,6,7 刪除
    ary1.splice(0,2,0);   // 0,3,4,5,6,7 替換 返回刪除的值
    // ary.splice(0,0,0)// 0,1,2,3,4,5,6,7增加
    for(var i=0;i<ary1.length;i++){
        var obj={};
        for(var j=i+1;j<ary1.length;j++){
            if(ary1[i]==ary1[j]){
                ary1.splice(j,1);
                j--;//防止數組塌陷
            }

        }
    }
    console.log(ary1)

• 數組去重2

    var ary=[3,3,4,2,5,3,6,1]
    Array.prototype.my=function(){
        var obj={};
        for(var i=0;i<this.length;i++){
            var cur=this[i];
            if(obj[cur]==cur){
                this.splice(i,1);
                i--;

            }else{
                obj[cur]=cur
            }
        }
    }
    ary.my();
    console.log(ary);

• 數組去重3

   var ary2=[3,3,4,2,5,3,6,1];

    function unique(arr){
        var res =[];
        var json = {};
        for(var i=0;i<arr.length;i++){

            if(!json[arr[i]]){
                res.push(arr[i]);

                json[arr[i]] = 1;

            }

        }
        return res;

    }
    unique(ary2)

• 數組去重4

     Array.prototype.unique = function () {
        var newArr = [];
        for (var i = 0; i < this.length; i++) {
            if (newArr.indexOf(this[i]) == -1) {
                newArr.push(this[i]);
            }
        }
        return newArr;
    }

• 數組去重5

    var myArray = ['a', 1, 'a', 2, '1',1,2,1];
    var unique1 = myArray.filter(function(v, i, a){ return a.indexOf(v) == i; });

console.log(unique1)