Accessing Array outside of the loop

Question

I have an Array where some different UserID's are stored. Each UserID is connected with their corresponding data in Firestore. So now I want to fetch all the JSON Data from the UserID's and make them accessible to decode them later. Therefore the fetched Data (coming as a Dictionary) from each user must be accessible separately. I tried it with that way:

var fetchedIDs = ["ID1", "ID2", "ID3"]
var finalArray = [[String: Any]]()

for id in fetchedIDs{  
                let docRef = Firestore.firestore().collection("Data").document(id)
                docRef.getDocument { (document, error) in
                    if let document = document, document.exists {
                       let myDict: [String: Any] = document.data() as! [String: Any] 
                        finalArray.append(myDict)
                    }    
                }     
            }   
        }

But the problem is that the finalArray (like finalArray[0]) is just accessible in the For-Loop. It should be accessible outside of the loop and look like that:
finalArray[0] should have the Dictionary data from ID1
finalArray[1] should have the Dictionary data from ID2
Maybe I am thinking to complicated for that.. Can someone help me out ?

Is there generally a good source for learning about scopes and how the data should be accessed like in that scenario? Thanks!

Are you sure this isn’t an asynchronous issue and that you try to access it before the data has been downloaded? — Joakim Danielson, Feb 23 '20 at 12:06
"Swift + Closure + Async" should be a good way to search. Do a print in `finalArray.append(myDict)` , do a print after the for loop. Which one will be printed first? — Larme, Feb 23 '20 at 12:30
@Larme The print after the for loop is the first one printed. — LoopingLouieX, Feb 23 '20 at 13:01
I know. It’s to point out the asynchrone of your code. Look as I said for « Swift async closure » — Larme, Feb 23 '20 at 13:03

score 1 · Answer 1 · answered Feb 23 '20 at 13:42

Finally get it working with the following code:

var fetchedIDs = ["ID1", "ID2", "ID3"]
func loadData(com:@escaping( ([[String: Any]]) -> ())){
                var myArray = [[String: Any]]()

                for id in fetchedIDs{
                    let refLike = db.collection("Data").document(id)
                    refLike.getDocument { (document, error) in
                        if let err = error {
                            print("Error getting documents: \(err)")
                        } else {
                            let myDict: [String: Any] = document?.data() as! [String: Any]
                            myArray.append(myDict)
                        }
                        com(myArray)
                    }
                }
            }


            loadData(){ arr in
                if (arr.count == fetchedIDs.count){
                    print ("User 1 has the following data: \(arr[0])")
                    print ("User 2 has the following data: \(arr[1])")
                }
            }

Accessing Array outside of the loop

1 Answers1