When creating your application, there might come a point where you need to create a list, or you might come to a point where you want to associate a bunch of values with a bunch of other values (like a real-life dictionary). To solve this problem, we will walk you through what an array is and what a dictionary is in this chapter. These are considered collection types in Swift and are very powerful.
This chapter will help you understand the following things:
An array is a collection type that allows you to store an ordered list of values
A dictionary is a collection type that is unordered and associates various keys with values
An optional is a type that handles the situation where there might not be a value