Swift: Appending object inside dictionary - ios

Question

I'd like to add my dictionary with array in it to my arrayOfDictionary, i tried the suggested answer on this link, but it didn't work for me. I'm having problem on appending object in my dictionary.
Here's my code:
func formatADate() {
var dateFormatter = NSDateFormatter()
dateFormatter.dateStyle = NSDateFormatterStyle.LongStyle
var journalDictionary = Dictionary<String, [Journal]>()
for index in 0..<self.sortedJournal.count {
let dateString = dateFormatter.stringFromDate(self.sortedJournal[index].journalDate)
var oldDateString = ""
// Split Date
var dateStringArr = split(dateString){$0 == " "}
var newDateString = "\(dateStringArr[0]) \(dateStringArr[2])"
// Append journal to corresponding dates
// journalDictionary[newDateString]? += [self.sortedJournal[index]]
// journalDictionary[newDateString]!.append(self.sortedJournal[index])
journalDictionary[newDateString]?.append(self.sortedJournal[index])
// add to array of journal
if !(newDateString == oldDateString) || (oldDateString == "") {
arrayOfJournalDictionary.append(journalDictionary)
}
}
println(arrayOfJournalDictionary)
}
With this line of code, it gives me empty object.
journalDictionary[newDateString]?.append(self.sortedJournal[index])
Any suggestion on how I can accomplish/fix this? I'm pretty amateur in Swift, so any help would be appreciated! Thank you.

Answer 1

Woah, date magic with string splits and stuff, yeiks. You already are using NSDateFormatters, for the wrong reasons though. Since journalDate is a date, use the formatter to give you the exact string you want from that date, dont let it give you some generic string and split and concatenate and argh... NOBODY will understand what you are trying to do there.
Back to the question:
Your journalDictionary is empty, if you write
journalDictionary[newDateString]?.append(self.sortedJournal[index])
You tell the program to read at "index" newDateString and if there is something take that and append a new value to it.
Do you see the mistake already?
if there is something -> You have no logic yet to insert the initial empty [Journal] for any given key.
At some point in your code you have to set up the array like so:
journalDictionary["myKey"] = []
Or probably more likely:
if journalDictionary[newDateString] == nil {
journalDictionary[newDateString] = [self.sortedJournal[index]]
} else {
journalDictionary[newDateString]?.append(self.sortedJournal[index])
}