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

Because Dictionary and Array are both struct types, you can't modify the Array in place, but instead have to extract and restore it:

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