Map with dictionaries

We can also map over the (key, value) pairs of a dictionary:

let numbers = ["1": "one", 
               "2": "two", 
               "3": "three"] 
let other = numbers.map({(key, val) in  
            (Int(key), val.uppercased())  
            }) 

This syntax takes a little getting used to; just remember, you need to create a tuple when reading the key and value of each dictionary element into the closure, and similarly return the new values as a tuple.