Swift dictionary with array as value

Question

How do you declare a dictionary that has an array as the value? Is this even possible?

Answer 1

Yes

let myDictionary: [String: [Int]] = ["Hello": [1, 2, 3], "World": [4, 5, 6]]

In fact, you don't even need the explicit type declaration if you assign an initial value in place. It can go as simple as:

let myDictionary = ["Hello": [1, 2, 3], "World": [4, 5, 6]]

To use the value:

println(myDictionary["Hello"][0]) // Print 1
println(myDictionary["World"][0]) // Print 4

Answer 2

 var dictionary : [String:[AnyObject]]

 var dictionary2 = [String:[AnyObject]]()

You can change AnyObject for any class or use it like AnyObject itself if you don't know the class that will be in the array.

Answer 3

If you want to store for example an array of strings:

var dict: [String: [String]]

or without syntactic sugar:

var dict: Dictionary<String, Array<String>>

Dictionaries, like arrays and more generally whatever uses generics, can handle anything that is a swift type, including tuples, closures, dictionaries, dictionaries of dictionaries, arrays of dictionaries, etc. - unless conditions are specified for the generic type (for instance, a dictionary key can be any type that implements the Hashable protocol), and in that case types must conform to the constraints.