CODEWITHSUNDEEP
iosjsonswiftnsdictionary
Mahi008
Mahi008

Reputation: 433

Swift - How to loop through NSDictionary

Hi I'm currently learning Swift, and I wanted to extract data from a JSON Api, My Swift code looks like this. To be specific, I need to extract each and every key and its value,(for example: print the value of title, cover etc..)

//Json request
var error: NSError?
var raw = NSString.stringWithString("http://example.com/MovieAPI/api/v1/movies/")
var api_url = NSURL.URLWithString(raw)
let jsonData: NSData = NSData.dataWithContentsOfURL(api_url, options: nil, error: &error)
let result = NSJSONSerialization.JSONObjectWithData(jsonData, options: nil, error: &error)
as NSDictionary
for val in result {
   for (var i=0; i < val.value.count; i++){
       //println(val.value.valueAtIndex(3)) Not Working
   }
}

and the structure of my JSON is

{
  data: [
      {
        id: 2,
        title: "Hunger Games",
        cover: "http://example.com",
        genre: 2
       }
  ]
}

Help!

Upvotes: 25

Views: 44412

Answers (2)

AppsWise
AppsWise

Reputation: 1254

Check this piece of code for reference: 

// MARK: - Firebase
func retrieveData(){
    ref.observe(FIRDataEventType.value, with: { (snapshot) in
        let postDict = snapshot.value as! [String : AnyObject]
        let contactList = postDict["contacts"]!
        let user = FIRAuth.auth()!.currentUser

        let contactArray = contactList[user!.uid]! as! NSDictionary

        for (key,_) in contactArray {

            let contact:NSObject = contactArray[key] as! NSObject
            let firstName:String! = contact.value(forKey: "firstName") as? String
            let lastName:String! = contact.value(forKey: "lastName") as? String
            let company:String! = contact.value(forKey: "company") as? String
            let phone:String! = contact.value(forKey: "phone") as? String
            let email:String! = contact.value(forKey: "email") as? String

            print(contact.value(forKey: "firstName")!)
            contacts.append(Contact(firstName:firstName, lastName: lastName, company: company, phone: phone, email: email))
        }
        self.tableView.reloadData()

    })

}

It specially gets tricky when you parse the key value into the usable object that is where the NSObject comes to rescue so that you can get the values for key.

Upvotes: 4

Keenle
Keenle

Reputation: 12190

Here is how you can process a given JSON:

let dataArray = result["data"] as NSArray;

print("Data items count: \(dataArray.count)")

for item in dataArray { // loop through data items
    let obj = item as NSDictionary
    for (key, value) in obj {
        print("Property: \"\(key as String)\"")
    }
}

Remarks:

Remember that you receive parsed objects as NSDictionary and when you iterate through the dictionary, order in which you receive properties may differ from the order in the original JSON.

Upvotes: 49

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