Reading Data from Firebase into Arrays - arrays

Question

Reading snapshots from firebase is fairly simple, although transferring the information to arrays is more complicated. I have this snapshot
Snap (01-08-2019) {
Sleep = "6.25 hrs";
"Time Uploaded" = "07:10 AM";
}
Snap (01-09-2019) {
Sleep = "6.72 hrs";
"Time Uploaded" = "07:19 AM";
}
Snap (01-10-2019) {
Sleep = "6.55 hrs";
"Time Uploaded" = "07:10 AM";
}
How would I be able to make one array for the date, one for the sleep, and one for the time uploaded.

Answer 1

I think you should reconsider how you store your data in firebase. To Look something similar to this.
Also I would consider to create a data model for day that looks something like this.
class Day {
var date: String
var sleep: String
var timeUploaded: String
init(date: String, sleep: String, timeUploaded: String) {
self.date = date
self.sleep = sleep
self.timeUploaded = timeUploaded
}
}
Then you can just fetch your snapshots like this.
var days = [Day]()
private func fetchDays() {
print(days.count)
let ref = Database.database().reference().child("days")
ref.observeSingleEvent(of: .value) { (snapshot) in
guard let days = snapshot.value as? [String: Any] else { return }
for (_,value) in days.enumerated() {
guard let dayDict = value.value as? [String: String] else { return }
let date = dayDict["date"] ?? ""
let sleep = dayDict["sleep"] ?? ""
let timeUploaded = dayDict["time_uploaded"] ?? ""
//If you really want 3 different arrays just add them here
// dateArray.append(date) and so on for the other two arrays
let day = Day(date: date, sleep: sleep, timeUploaded: timeUploaded)
self.days.append(day)
}
print(self.days.count)
}
}
}
Hope this helps. Couldn't comment to ask how your data was structured.

Answer 2

I would suggest not keeping the data in different arrays, it may be better to store the data from each node within a class, and then keep an array of those classes.
Let's start with a class that keeps all of the data
class ChronoClass {
var node_id = ""
var sleep = ""
var time_uploaded = ""
init(withSnapshot: DataSnapshot) {
let nodeId = withSnapshot.key
let someSleep = withSnapshot.childSnapshot(forPath: "sleep").value as? String ?? ""
let someTime = withSnapshot.childSnapshot(forPath: "time_uploaded").value as? String ?? ""
self.node_id = nodeId
self.sleep = someSleep
self.time_uploaded = someTime
}
}
and then a class array to keep all of the classes
var sleepArray = [ChronoClass]()
and finally the code to read in each node, populate the class and store the classes in an array.
func readFirebaseDataAndPopulateArray() {
let sleepNode = self.ref.child("sleep_node")
sleepNode.observeSingleEvent(of: .value, with : { snapshot in
for child in snapshot.children {
let snap = child as! DataSnapshot
let aChrono = ChronoClass(withSnapshot: snap)
self.sleepArray.append(aChrono)
}
for x in self.sleepArray { //just prints out what's in the array
print(x.node_id, x.sleep, x.time_uploaded)
}
})
}
and the output based on your structure
01-08-2019 6.25 hrs 07:10 AM
01-09-2019 6.72 hrs 07:19 AM
01-10-2019 6.55 hrs 07:10 AM
The advantage with using a class is you can sort, search, extrapolate or do a variety of other functions on the objects instead of working with three separate arrays.