using integerForKey with strings swift - ios

Question

I am confused about using integer for key in swift. Can someone explain how this works and what value it will return? I would expect it to be able to return an integer associated with a key in a dictionary or array, but don't understand how it will return an integer for a string?
import Foundation
// adopted by delegate so it can be notified when settings change
protocol ModelDelegate {
func settingsChanged()
}
class Model {
private let regionsKey = "FlagQuizKeyRegions"
private let guessesKey = "FlagQuizKeyGuesses"
// reference to QuizViewController to notify it when settings change
private var delegate: ModelDelegate! = nil
var numberOfGuesses = 4 // number of guesses to display
private var enabledRegions = [
"Africa" : false,
"Asia" : false,
"Europe" : false,
"North_America" : true,
"Oceania" : false,
"South_America" : false
]
// variables to maintain quiz data
let numberOfQuestions = 10
private var allCountries: [String] = [] // list of all flag names
private var countriesInEnabledRegions: [String] = []
// initialize the settings from the app's NSUserDefaults
init(delegate: ModelDelegate, numberOfQuestions: Int) {
self.delegate = delegate
// get the NSUSerDefaults object for the app
let userDefaults = NSUserDefaults.standardUserDefaults()
// get number of guesses
let tempGuesses = userDefaults.integerForKey(guessesKey)
if tempGuesses != 0 {
numberOfGuesses = tempGuesses
}

Answer 1

It will return a Integer for a key which is a String. So let's say:
let myKey = "Countries"
let myCountries = ["USA","Brazil","Japan"]
NSUserDefaults.standardUserDefaults().setInteger(myCountries.count, forKey: myKey)
let numberOfCountries = NSUserDefaults.standardUserDefaults().integerForKey(myKey) // 3