ios - How to parse JSON data properly if some data is NSNull -

i'm pulling data via twitter's search api.

once receive data, trying parse , save data tweetdetails class (which hold author's name, url of profile pic, text of tweet, location of tweet, tweet id , user id).

in cases, tweets not have location (i think has if they're retweeted), , dictionary (here being tweetsdict["place"]) otherwise hold information, instead returns nsnull.

on occasions, receive error

could not cast value of type 'nsnull' (0x1093a1600) 'nsdictionary' (0x1093a0fe8).

here code trying parse data , save objects in tweetdetails class

    client.sendtwitterrequest(request) { (response, data, connectionerror) -> void in         if connectionerror != nil {             print("error: \(connectionerror)")         }         {             let json = try nsjsonserialization.jsonobjectwithdata(data!, options: [])              if let tweets = json["statuses"] as? [nsdictionary] {                 tweetsdict in tweets {                     let text = tweetsdict["text"] as! string                     let tweetid = tweetsdict["id_str"] as! string                     let place = tweetsdict["place"] as! nsdictionary                      // line ^^ error occurs                     let city = place.valueforkey("full_name")                     let user = tweetsdict["user"] as! nsdictionary                     let userid = user.valueforkey("id_str")                     let screenname = user.valueforkey("screen_name")!                     let avatarimage = user.valueforkey("profile_image_url_https")!                      let tweet = tweetdetails(authors: screenname as! string, profileimages: avatarimage as! string, tweettexts: text, tweetlocations: city as! string , tweetids: tweetid , userids: userid as! string)                     self.alltweets.append(tweet)                     self.tweettableview.reloaddata()                 }             }         } catch let jsonerror nserror {             print("json error: \(jsonerror.localizeddescription)")         }     } 

i have tried create 'if-let' statements provide alternatives these occasions, nothing has worked.

could please me create custom alternative around when json data returns nsnull. (even simple turning "city" variable string "unknown location" in cases when data returns nsnull).

thanks in advance , please let me know if there else can add provide more clarity question.

as others have pointed out, can use optional binding (if let), or, in case, easier, employ optional chaining:

let city = tweetsdict["place"]?["full_name"] as? string  

this way, city optional, i.e. if no value found because there no place or full_name entry, nil.

it appear, though, tweetdetails force casting city string. absolutely require city? best change method city optional , gracefully handle nil values there. alternatively, can replace nil values city other string, e.g. nil coalescing operator:

let city = tweetsdict["place"]?["full_name"] as? string ?? "unknown city" 

that returns city if found, , "unknown city" if not.