Table Of ContentSwift Apprentice
Swift Apprentice
Janie Clayton, Alexis Gallagher, Matt Galloway, Eli Ganem, Erik Kerber, Ben Morrow,
Cosmin Pupăză and Steven Van Impe
Copyright ©2016 Razeware LLC.
Notice of Rights
All rights reserved. No part of this book or corresponding materials (such as text,
images, or source code) may be reproduced or distributed by any means without
prior written permission of the copyright owner.
Notice of Liability
This book and all corresponding materials (such as source code) are provided on an
“as is” basis, without warranty of any kind, express of implied, including but not
limited to the warranties of merchantability, fitness for a particular purpose, and
noninfringement. In no event shall the authors or copyright holders be liable for any
claim, damages or other liability, whether in action of contract, tort or otherwise,
arising from, out of or in connection with the software or the use of other dealing in
the software.
Trademarks
All trademarks and registered trademarks appearing in this book are the property of
their own respective owners.
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Swift Apprentice
Dedications
"Here's to the crazy ones. Except Josh. He knows what he did."
— Janie Clayton
"To my wife, and her remarkable patience in the face of the
rationally inexplicable features of my writing process."
— Alexis Gallagher
"To my amazing family who keep putting up with me spending my
spare hours writing books like this."
— Matt Galloway
"To the two loves of my life, Moriah and Lia."
— Eli Ganem
"To the Swift community, both old and new — and to Brigette,
who puts up with my long hours at the keyboard to help make
this book possible."
— Erik Kerber
"For MawMaw. A talented cook, a loving smooch, a worthy
opponent in chicken foot; a home weaver. Her blessing abides
beyond her time."
— Ben Morrow
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Swift Apprentice
"To my Mum and Dad, for their total encouragement, entire trust,
unconditional support and completely believing in me all the way
with everything I do no matter what. To my grandmother, whom I
miss a lot and do hope I make her proud with all the things I
accomplish. To Irina and Gordon, for talking to me and listening
to me when I needed it the most. To Ray and Vicki, for believing
in me all the way and encouraging me to write tutorials and this
book."
— Cosmin Pupăză
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Swift Apprentice
About the authors
Janie Clayton is an independent iOS developer. She spent a year
apprenticed to a super genius programming robots and learning
the forgotten ways of long term software maintenance and
development. Janie is the coauthor on several books on iOS and
Swift development. Janie lives outside of Madison, Wisconsin with
her attempted grumble of pugs and multitude of programming
books. Janie writes her various musings on her blog at
RedQueenCoder.com.
Alexis Gallagher is a software engineer who is always looking for
the conceptual deep dive and always hoping to find pearls down at
the bottom. When he’s not coding, he’s out and about in sunny
San Francisco.
Matt Galloway is a software engineer with a passion for
excellence. He stumbled into iOS programming when it first was a
thing, and has never looked back. When not coding, he likes to
brew his own beer.
Eli Ganem is an engineer at Facebook. He is passionate about
teaching, writing, and sharing his knowledge with others.
Erik Kerber is a software developer in Minneapolis, MN, and the
lead iOS developer for the Target app. He does his best to balance
a life behind the keyboard with cycling, hiking, scuba diving, and
traveling.
Ben Morrow delights in discovering the unspoken nature of the
world. He’ll tell you the surprising bits while on a walk. He
produces beauty by drawing out the raw wisdom that exists within
each of us.
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Swift Apprentice
Cosmin Pupăză is a software developer and tutorial writer from
Romania and this is his first book. He is part of the Swift tutorial
teams at AppCoda and raywenderlich.com. He has worked with
more than a dozen programming languages, technologies,
frameworks, tools and libraries over the years, but none of them
has made such a great impact on himself as the advent of Swift.
When not coding, he either plays the guitar or studies WWII
history, and he hopes you enjoy reading the book just as much as
he enjoyed writing it. Cosmin blogs about Swift at
cosminpupaza.wordpress.com.
About the editors
Steven Van Impe is the technical editor of this book. Steven is a
computer science lecturer at the University College of Ghent,
Belgium. When he’s not teaching, Steven can be found on his bike,
rattling over cobblestones and sweating up hills, or relaxing
around the table, enjoying board games with friends. You can find
Steven on Twitter as @svanimpe.
Chris Belanger is the editor of this book. Chris Belanger is the
Book Team Lead and Lead Editor for raywenderlich.com. If there
are words to wrangle or a paragraph to ponder, he’s on the case.
When he kicks back, you can usually find Chris with guitar in hand,
looking for the nearest beach, or exploring the lakes and rivers in
his part of the world in a canoe.
Ray Fix is the final pass editor of this book. Ray Fix is a software
developer from Southern California who is passionate about
technology, communication, and helping people become their best.
In addition to his role as Swift Team Lead for raywenderlich.com,
he is an organizer for the Orange County iOS developer group and
a board member for the non-profit, San Diego iOS group. Ray is
semi-fluent in spoken and written Japanese and stays healthy by
walking, jogging and playing ultimate frisbee. When he is not
doing one of those things, he is writing and dreaming of code in
Swift!
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Swift Apprentice
Table of Contents: Overview
Introduction................................................................................ 16
Section I: Swift Basics .................................................. 22
Chapter 1: Coding Essentials & Playground Basics .. 24
Chapter 2: Expressions, Variables & Constants......... 36
Chapter 3: Types & Operations................................... 51
Chapter 4: Basic Control Flow ...................................... 67
Chapter 5: Advanced Control Flow ............................. 84
Chapter 6: Functions ....................................................... 99
Chapter 7: Optionals................................................... 112
Section II: Collection Types ........................................ 124
Chapter 8: Arrays......................................................... 126
Chapter 9: Dictionaries................................................ 139
Chapter 10: Collection Iteration with Closures........ 148
Section III: Building Your Own Types......................... 159
Chapter 11: Structures................................................. 161
Chapter 12: Properties................................................ 173
Chapter 13: Methods................................................... 185
Chapter 14: Classes..................................................... 198
Chapter 15: Advanced Classes.................................. 213
Chapter 16: Enumerations........................................... 233
Chapter 17: Protocols.................................................. 249
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Chapter 18: Generics .................................................. 266
Section IV: Advanced Topics...................................... 281
Chapter 19: Access Control and Code
Organization.................................................................. 282
Chapter 20: Custom Operators and Subscripts...... 296
Chapter 21: Pattern Matching ................................... 305
Chapter 22: Error Handling........................................ 324
Chapter 23: Asynchronous Closures and Memory
Management.................................................................. 341
Chapter 24: Value Types and Value Semantics...... 354
Chapter 25: Protocol-Oriented Programming ........ 369
Conclusion ............................................................................... 383
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Swift Apprentice
Table of Contents: Extended
Introduction................................................................................ 16
Who this book is for.......................................................................................................... 16
What you need.................................................................................................................. 17
How to use this book......................................................................................................... 17
What's in store................................................................................................................... 19
Book source code and forums......................................................................................... 19
Book updates...................................................................................................................... 20
License.................................................................................................................................. 20
Acknowledgments.............................................................................................................. 20
About the cover.................................................................................................................. 21
Section I: Swift Basics .................................................. 22
Chapter 1: Coding Essentials & Playground Basics .......... 24
How a computer works..................................................................................................... 24
Playgrounds........................................................................................................................ 30
Key points............................................................................................................................ 34
Where to go from here?.................................................................................................. 35
Chapter 2: Expressions, Variables & Constants................. 36
Code comments.................................................................................................................. 36
Printing out.......................................................................................................................... 37
Arithmetic operations........................................................................................................ 38
Math functions..................................................................................................................... 42
Naming data...................................................................................................................... 43
Increment and decrement................................................................................................. 47
Key points............................................................................................................................ 48
Where to go from here?.................................................................................................. 48
Challenges........................................................................................................................... 49
Chapter 3: Types & Operations........................................... 51
Type conversion.................................................................................................................. 51
Strings.................................................................................................................................. 55
Strings in Swift.................................................................................................................... 58
Tuples................................................................................................................................... 60
A whole lot of number types........................................................................................... 62
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A peek behind the curtains: Protocols............................................................................ 63
Key points............................................................................................................................ 64
Where to go from here?.................................................................................................. 65
Challenges........................................................................................................................... 65
Chapter 4: Basic Control Flow............................................... 67
Comparison operators...................................................................................................... 67
The if statement.................................................................................................................. 72
Loops.................................................................................................................................... 77
Key Points............................................................................................................................ 80
Where to go from here?.................................................................................................. 81
Challenges........................................................................................................................... 81
Chapter 5: Advanced Control Flow...................................... 84
Ranges.................................................................................................................................. 84
For loops.............................................................................................................................. 85
Switch statements............................................................................................................... 91
Key points............................................................................................................................ 96
Where to go from here?.................................................................................................. 97
Challenges........................................................................................................................... 97
Chapter 6: Functions................................................................ 99
Function basics.................................................................................................................... 99
Functions as variables..................................................................................................... 106
Key points......................................................................................................................... 109
Where to go from here?................................................................................................ 109
Challenges........................................................................................................................ 110
Chapter 7: Optionals ........................................................... 112
Introducing nil................................................................................................................... 112
Introducing optionals....................................................................................................... 114
Unwrapping optionals.................................................................................................... 116
Introducing guard............................................................................................................ 119
Nil coalescing................................................................................................................... 121
Key points......................................................................................................................... 121
Where to go from here?................................................................................................ 122
Challenges........................................................................................................................ 122
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