How to append to an array that is a value in a Swift dictionary

Question

Let\'s assume I have a dictionary that accepts a string as the key and an array as value:

var d = [String: [Int]]()
d[\"k\"] = [Int]()

Now I wo

Answer 1

If the element for that key exists, you can simply do:

d["k"]?.append(1)

Note that if no element exists for the "k" key, then nothing happens. If you want to ensure there's actually an array for that key, just add this before appending:

if d["k"] == nil {
    d["k"] = []
}