Retrieving an array from Firebase

Question

I have an array in Firebase composed of 1's and 0's (true and false basically), they are all stored as separate key/value pairs. I would like to retrieve them from Firebase and append each value to an array in Swift.

I have tried this (found elsewhere on SO) but it is not working.

let ref = Firebase(url:"https://<<unique>>.firebaseio.com/users/\(self.UUID)/scoreArray")
    ref.observeSingleEventOfType(.Value, withBlock: { snapshot in
        if snapshot.value is NSNull {
            print("snap is null")
        } else {
            let enumerator = snapshot.children
            while let rest = enumerator.nextObject() as? FDataSnapshot {
                self.scoreArray.append(rest.value! as! String)
            }
        }
    })

It doesn't crash, it just doesn't fill the array, even though if I print(rest.value) it will give me the array.

So I guess the question is, how do I convert rest.value into a usable form?

EDIT Firebase structure as requested.

66EC8AC4-<<rest of UUID>>
     creation_date: "Jun 10, 2016"
         extra_quiz_1
             q1: "a"
             q10: "b"
             <<Continues>>
             scoreArray
                 0: "0"
                 1: "1"
                 2: "0"
                 3: "0"
                 <<continues>>

Can you please post your Firebase structure (as text please, no images. Firebase Console->Three dots on right->Export JSON). Also, arrays (in Firebase) are inherently difficult to work with as you cannot insert, edit or access the individual elements, so there may be a better structure that will simplify the solution. — Jay, Jun 11 '16 at 12:28
@Shubhank The difference is the variable key. Those examples the key remains the same so iterating is a bit easy. My key changes to represent the question number. — Craig.Pearce, Jun 11 '16 at 12:58
the key is diff in them you should try those answers. @Jay he has edited his question for you to take a look on. — Shubhank, Jun 11 '16 at 14:11

Jay · Answer 1 · 2016-06-11T14:42:09.120

Working with Array's in Firebase is challenging and in general there are better options to structure data.

In this use case, it may work so here's how it's done.

Given a structure similar to yours:

quiz_0
  quiz_name: The Planets
  scores
     0: Mercury
     1: Venus
     2: Earth

here's how you would read in the data

    let quizzesRef = self.myRootRef.childByAppendingPath("quizzes")

    quizzesRef.observeEventType(.Value, withBlock: { snapshot in

        for child in snapshot.children {
            let quiz_name = child.value["quiz_name"] as! String
            print(quiz_name)
            let scores = child.value["scores"] as! NSArray
            print(scores) //scores is an array
            let answer0 = scores[0] //just to demonstrate accessing the array
            print(answer0)
        }
    })

and the output

Planets
(
    Mercury,
    Venus,
    Earth
)
Mercury

That being said, don't use arrays. Here's a suggestion that may be a far more flexible. Renumbering questions is a snap, modifying the question or answer is easy as well. The -Asidijaid keys are generated using childByAutoId - helps to disassociate dynamic data from static keys.

quiz_0
  quiz_name: The planets
  quiz_data
    -Asok99idkasdsl
       question_number: 0
       question: Which planet closet to the Sun?
       answer: Mercury
    -Yklaosokjdinoisd
       question_number: 1
       question: Which rocky planet is hotter than Mercury
       answer: Venus
    -Klkooksow999sdd
       question_number: 2
       question: What is the third planet from the Sun
       answer: Earth

Retrieving an array from Firebase

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