var pureMulti1=function(arr){
  var obj={};
  var a = [];
  for(var i=0,l=arr.length;i < l;i++){
      if(!(arr[i] in obj)){
        a.push(arr[i]);
      }
      obj[arr[i]]="";
  }
  return a;
}

var pureMulti4=function (arr){
  var obj={};
  var a = [];
  for(var i=0,l=arr.length;i < l;i++){
	  (!(arr[i] in obj)) && a.push(arr[i]) && (obj[arr[i]]="");
  }
  return a;
}

var pureMulti2=function (arr){
  var str = [];
  for(var i = 0,len = arr.length;i < len;i++){
	!new RegExp(arr[i],"g").test(str.join(",")) && (str.push(arr[i]));
  }
  return str;
}