Appending to UserDefaults Array (Swift)

Question

I want to create an array of Ints that I can append to and will be saved to UserDefaults so that next time the user opens the app, the array will be saved. So, I know how to create a UserDefaults array...

var intArray = UserDefaults.standard.array(forKey: "intArray") as! [Int]

and I know how to set the array to an already existing array:

var array = [2, 6, 34, 4, 9]
UserDefaults.standard.set(array, forKey: "intsArray")

But, I need the array to be empty and then the user adds Ints to the array. Thanks for your help!

Answer 1

I would suggest you to create a computed property for this purpose:

var intArray: [Int] {
    get {
        return UserDefaults.standard.array(forKey: "intArray") as? [Int] ?? []
    }
    set {
        UserDefaults.standard.set(newValue, forKey: "intArray")
    }
}

Now whenever you modify your intArray it will update its value in UserDefaults and whenever you call intArray it returns you the value from UserDefaults.

Answer 2

Not sure about what you need.

However this is how you add an empty array to UserDefaults

 UserDefaults.standard.set([Int](), forKey: "nums")

And this is how you

1. load the array from UserDefaults
2. add a value
3. save it again to UserDefaults

.

var nums = UserDefaults.standard.array(forKey: "nums") as! [Int]
nums.append(1)
UserDefaults.standard.set(nums, forKey: "nums")