Book Image

Mastering Swift 3

Book Image

Mastering Swift 3

Overview of this book

Swift is the definitive language of Apple development today. It’s a vital part of any iOS and OS X developer’s skillset, helping them to build the most impressive and popular apps on the App Store—the sort of apps that are essential to iPhone and iPad users every day. With version 3.0, the Swift team have added new features to improve the development experience—making it easier to get the results you want and customers expect. Inside, you’ll find the key features of Swift 3.0 and quickly learn how to use the newest updates to your development advantage. From Objective-C interoperability to ARC, to closures and concurrency, this advanced Swift guide will develop your expertise and make you more fluent in this vital programming language. We give you in-depth knowledge of some of the most sophisticated elements of Swift development including protocol extensions, error-handling, design patterns, and concurrency, and guide you on how to use and apply them in your own projects. You'll see how even the most challenging design patterns and programming techniques can be used to write cleaner code and to build more performant iOS and OS X applications. By the end of this book, you’ll have a handle on effective design patterns and techniques, which means you’ll soon be writing better iOS and OS X applications with a new level of sophistication and control.
Table of Contents (23 chapters)
Mastering Swift 3
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Free Chapter
1
Taking the First Steps with Swift
2
Learning About Variables, Constants, Strings, and Operators

Mutability


For those who are familiar with Objective-C, you will know that there are different classes for mutable and immutable collections. For example, to define a mutable array, we use the NSMutableArray class, and to define an immutable array, we use the NSArray class. Swift is a little different, because it does not contain separate classes for mutable and immutable collections. Instead, we define whether a collection is constant (immutable) or a variable (mutable) by using the let and var keywords. This should seem familiar since, in Swift, we define constants with the let keyword and variables with the var keyword.

Note

It is good practice to create immutable collections unless there is a specific need to change the objects within the collection. This allows the compiler to optimize performance.

Let's begin our tour of collections by looking at the most common collection type—the array type.