javaScript数组去重方法汇总

方法一

function toAgaing(){
               var result = [],
                          flag = false;
                          for(var i = 0; i < this.length; i++){
                              if(this[i] !=this[i]){
                                  if(flag){
                                      continue;
                                  }else{
                                      flag = true;
                                      result.push(this[i]);
                                  }
                              }else if(result.indexOf(this[i]) == -1){
                                  result.push(this[i]);
                              }
                          }

                          return result;
           }
           Array.prototype.again = toAgaing;
           var x = new Array(1,1,2,2,3,3,4,4,5);
           console.log(x.again());

 

方法二

function Again(){
               var res = [];

               for(var i = 0 ; i < this.length; i++){

                   var flag = false;

                   for(var j = 0; j < res.length; j ++){

                       if(this[i] == res[j]){

                           flag = true;
                           break;
                       }
                   }

                   if(!flag){
                       res.push(this[i]);
                   }

               }
               return res;
           }

           Array.prototype.toAgaing = Again;

           var x = new Array(1,1,2,2,3,3,4,4,5);
           console.log(x.toAgaing());

 

方法三

function Again(){
               this.sort();

               var res = [];

               for (var i = 0; i < this.length; i++) {
                   if(this[i] != res[res.length - 1]){
                       res.push(this[i]);
                   }
               }
               return res;
           }

           Array.prototype.toAgaing = Again;

           var x = new Array(1,1,2,2,3,3,4,4,5);
           console.log(x.toAgaing());

 

方法四

function Again(){
               var res = [],
                      obj = {};

                      for (var i = 0; i < this.length; i++) {
                          
                          if(!obj[this[i]]){

                              res.push(this[i]);

                              obj[this[i]] = 1;

                          }
                      }
                      return res;
           }
           Array.prototype.toAgaing = Again;

           var x = new Array(1,1,2,2,3,3,4,4,5);
           console.log(x.toAgaing());