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

Subscripts with Swift arrays


The following example shows how to use subscripts to access and change the values of an array:

var arrayOne = [1,2,3,4,5,6] 
print(arrayOne[3])  //Displays '4' 
arrayOne[3] = 10 
print(arrayOne[3])  //Displays '10' 

In the preceding example, we create an array of integers and then use the subscript syntax to display and change the item at index 3 in the array. Subscripts are mainly used to get or retrieve information from a collection. We generally do not use subscripts when specific logic needs to be applied to determine which item to select. As examples, we will not use subscripts to append an item to the end of the array or to retrieve the number of items in the array. To append an item to the end of an array, or to get the number of items in an array, we will use functions or properties, such as this:

arrayOne.append(7)  //append 7 to the end of the array 
arrayOne.count  //returns the number of items in an array 

Subscripts in...