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

Like this:

var d = [String: [Int]]()
d["k"] = [Int]()
if var items = d["k"] {
    items.append(1)
    d["k"] = items
}

You have to:

1. pull it out
2. unwrap the Optional
3. assign it to a var reference
4. append, and
5. put it back again

The if var line does the first three steps all in one.