In the previous lesson, we looked into building Swift functions, error handling, and developing fully-featured Swift programs. We also briefly looked at a few OOP features.

In this lesson, we will work extensively with Swift's collections, such as arrays, sets, and dictionaries.

The Swift Standard Library ( https://developer.apple.com/documentation/swift) is automatically imported into all Swift code, and contains basic types such as Int, Double, Bool, Optional, and more. It is primarily organized around protocols, because Swift is a Protocol-Oriented language ( https://developer.apple.com/videos/play/wwdc2015/408/).

The root protocol for collections, which they all inherit from, is Sequence. All a type needs to conform to it is the ability to provide one value at a time, until it is empty, at which point it will output nil. This simple requirement provides a long list of methods ( https://developer.apple.com/documentation...