JavaScript与Python去除字符串重复字符的实现

function dropRepeat(str){
 var result=[];
 var hash={};
 for(var i=0, elem; i<str.length;i++){
  elem=str[i];
  if(!hash[elem]){
   hash[elem]=true;
   result=result+elem;
  }
 }
 return result;
}

dropRepeat("abcdd") 

python 2.7：
#-*- encoding:utf-8 -*-
string = 'abc123456ab2s'
r = ''.join(x for i, x in enumerate(string) if string.index(x) == i)
print string
print r