Firebase saving multiple child values to arrays - arrays

Question

Looking at the structure of my firebase database:
I am attempting to save the values for every key for every cryptocurrency into separate arrays.
For example, the 'coinAmount' key, I would like to get an array looking like ["1.0,"2.0"], and 'coinName' as ["Bitcoin","Ethereum"] etc for each of the 5 keys.
My attempt at this:
let index = NSIndexPath(item: 0, section: 0)
if portfolioCoinFullNameString.count > 0 {
print("PortfolioVC: Number of Coins in Portfolio > 0")
let coinRef = ref.child("\(portfolioCoinFullNameString[index.row])")
coinRef.observe(DataEventType.value) { (snapshot) in
for child in snapshot.children {
let snap = child as! DataSnapshot
let key = snap.key
let value = snap.value
print("key = \(key) ,, value = \(value!)")
if key == "coinAmount" {
self.firebaseCoinAmountArray.append(Double(value as! String)!)
} else if key == "coinName" {
self.firebaseCoinNameArary.append(value as! String)
} else if key == "coinPrice" {
self.firebaseCoinPriceArray.append(Double(value as! String)!)
} else if key == "coinSymbol" {
self.firebaseCoinSymbolArray.append(value as! String)
} else if key == "coinTotalFiat" {
self.firebaseCoinTotalFiatArray.append(Double(value as! String)!)
} else {
print("PortfolioVC: Key does not match anything!")
}
}
}
} else {
print("PortfolioVC: Number of Coins in Portfolio !> 0")
}
This works for adding the first coin, but when i attempt to add the second one the 2 values are appended to the array so it contains 3, and if i add a third coin it append 3 values. Not sure why its looping through each coin?
EDIT:
I searched around StackOverflow and came across another method:
let index = NSIndexPath(item: 0, section: 0)
if portfolioCoinFullNameString.count > 0 {
print("PortfolioVC: Number of Coins in Portfolio > 0")
let coinRef = ref.child("\(portfolioCoinFullNameString[index.row])")
coinRef.observe(DataEventType.value) { (snapshot) in
let value = snapshot.value as? NSDictionary
let coinName = value?["coinName"] as? String ?? ""
self.firebaseCoinNameArary.append(coinName)
print("aaaaaa:\(self.firebaseCoinNameArary)")
}
} else {
print("PortfolioVC: Number of Coins in Portfolio !> 0")
}
But still have the issue of when adding any coin as second element in the array, the array contains 3x first coin added instead of just two entires of the first coin and second coin. I know i could do an if statement to check if the array already contains the name and if it does dont add it, but how would i do this with the number values as theres the possibility coins could have the same price.??
Edit2: Been thinking about it, would it work if i just observe the values and not for changes, save all of the to Arrays, populate the cells with them. Then if a user edits the 'coinAmount' value in the app, it updates in Firebase, but not the arrays. Then, upon user closing app/logging out, next time portfolio is shown it will re-pull the values from firebase which contains the updated numbers?
Edit3: Also, the nodes under portfolio called 'Bitcoin' etc, if i called them coin1, coin2, coin3 etc, how would i get that path and get the key and values for say coin3? Is there a way to just get the values for All the nodes under 'protfolio' in one go?
The idea is once I save all the firebase data to the arrays i will populate a tableview cell with all of the data.
Any help is appreciated :)
Thanks,
Jeremy

Answer 1

In order to do this don't use a for-loop use .childAdded
I will provide an example
database.ADD THE ENTIRE PATH.child("portfolio").observe(DataEventType.childadded) { (snapshot) in
let key = snapshot.key
let value = snapsnapshot.value as? NSDictionary
//Add everything that is in your firebase
let coinAmount = value?["coinAmount"] as? String
let cointName = value?["coinName"] as? String
//.... Added all the variables for the database
//use the variables above and append the array and it will work!
}
}