swift - Parse.com, disable a UIButton based on an object value -

i try build system parse. here's how try that: first when user click on button, associate post id user:

 @ibaction func likebuttonpressed(sender: anyobject) {       var id: anyobject! = self.object.objectid     let user = pfuser.currentuser()     user.addobject(id, forkey: "liked")     user.save() 

this part work correctly. now, want sure user each post once. that,

check if post id value allready (or not) in liked list

var liked = pfuser.currentuser().objectforkey("liked") [string]      id in liked{         if id == id{             found = true         }     }      if found{         likebutton.enabled = false     }     else{         likebutton.enabled = true     } 

if post id in liked list likebutton disable. unfortunately last part doesn't work (the button stil clickable). i'm beginner don't see where's problem code thank much

if id == id 

while not familiar swift, comparison hold true. try renaming 1 of variables comparing.