In this lesson, we will take a brief look at functional programming and learn what lazy operations are. We will end with an important but often overlooked topic: writing Swifty code.

Functional programming is a style of programming which tries to keep things simple by avoiding state, especially mutable state, and using a relatively small set of highly versatile functions/methods which take other functions as input. The Swift Standard Library contains several of these. They often make the code shorter, simpler, and easier to read if you know what they do. They can also free you from the burden of having to come up with names for temporary variables. Even if you don't use them in your own code, it is important to know how they work as a lot of Swift code out there uses them.