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());