Functional Swift

Tony joins Joe to introduce some functional programming concepts in Apple's new language, Swift. Tony uses the magic of Apple's new playgrounds to demonstrate some simple functional ideas, such as functions as values, closures, currying, enums, an...
This is a companion discussion topic for the original entry at https://thoughtbot.com/upcase/videos/functional_swift

I don’t understand the purpose of flatMap(). How are it’s results different from map?