INTRODUCTION xxiii CHAPTER 1: INTRODUCTION TO SWIFT 1 What Is Swift? 2 Why Swift Is Important 3 Setting Up the Environment 3 Creating a Playground Project 4 Creating an iOS Project 6 Swift Syntax 10 Constants 10 Variables 12 String Interpolation: Including Values in Strings 14 Statements 14 Printing 15 Comments 15 Summary 17 CHAPTER 2: DATA TYPES 19 Basic Data Types 20 Integers 20 Types of Integers 21 Integer Operations 22 Integer Literals 22 Floating?]Point Numbers 23 Floating?]Point Operations 23 Floating?]Point Literals 24 Type Alias 25 Boolean 25 Tuples 26 Optional Types 27 Implicitly Unwrapped Optionals 28 Optional Binding 29 Unwrapping Optionals Using "?" 30 Enumerations 30 Using Enumeration in Switch Statements 31 Enumeration Raw Values 32 Auto?]Increment for Raw Values 33 Associated Values 34 Enumeration Functions 35 Summary 36 CHAPTER 3: STRINGS AND CHARACTERS 39 Strings 40 Mutability of Strings 40 Strings as Value Types 40 Characters 41 Concatenating Strings 43 Special Characters 44 Unicode 45 Common String Functions 46 Equality 46 Prefi x and Suffi x 47 Length 47 Substrings 48 Converting Strings to Arrays 51 Type Conversion 51 Interoperability with NSString 52 Casting String to NSString 53 Using NSString Directly 54 String or NSString? 55 Summary 56 CHAPTER 4: BASIC OPERATORS 59 Assignment Operator 60 Arithmetic Operators 61 Addition Operator 61 Subtraction Operator 62 Multiplication Operator 62 Division Operator 63 Modulus Operator 63 Increment and Decrement Operator 63 Compound Assignment Operators 65 Nil Coalescing Operator 65 Comparison Operators 66 Equal To and Not Equal To 66 Greater Than or Equal To 67 Less Than or Equal To 67 Range Operators 68 Logical Operators 69 NOT 69 AND 70 OR 71 Combining Logical Operators 71 Ternary Conditional Operator 72 Summary 73 CHAPTER 5: FUNCTIONS 75 Defi ning and Calling a Function 76 Input Parameters 76 Returning a Value 76 Returning Multiple Values 77 Function Parameter Names 77 External Parameter Names Shorthand 79 Default Parameter Values 79 Variadic (Variable) Parameters 80 Constant and Variable Parameters 81 In?]Out Parameters 82 Function Types 83 Defining a Function Type Variable 83 Calling a Function Type Variable 84 Returning Function Type in a Function 85 Nested Functions 85 Summary 86 CHAPTER 6: COLLECTIONS 89 Arrays 90 Mutability of Arrays 90 Array Data Types 90 Retrieving Elements from an Array 91 Inserting Elements into an Array 91 Modifying Elements in an Array 92 Appending Elements to an Array 92 Checking the Size of an Array 93 Removing Elements from an Array 93 Iterating over an Array 93 Creating an Empty Array 94 Testing Arrays for Equality 95 Dictionaries 96 Mutability of Dictionaries 97 Retrieving Elements from a Dictionary 97 Checking the Size of a Dictionary 98 Modifying an Item in the Dictionary 98 Removing an Item from the Dictionary 99 Iterating over a Dictionary 99 Creating an Empty Dictionary 101 Testing Dictionaries for Equality 101 Copying the Behavior of Arrays and Dictionaries 102 Summary 103 CHAPTER 7: CONTROL FLOW AND LOOPING 107 Flow Control 108 If Statement 108 If?]Else Statement 109 Switch Statement 110 Matching Numbers 111 Matching Characters 112 Fallthrough 112 Matching a Range of Numbers 113 Matching Tuples 114 Value Bindings 115 Where Clause 117 Looping 118 For?]In Loop 118 Traditional For Loop 121 While Loop 122 Do?]While Loop 123 Control Transfer Statements 124 Break Statement 124 Continue Statement 126 Labeled Statement 126 Summary 128 CHAPTER 8: STRUCTURES AND CLASSES 131 Structures 132 Memberwise Initializers 132 Structures as Value Types 133 Comparing Structures 135 Classes 135 Defining a Class 136 Properties 136 Stored Properties 136 Lazy Stored Properties 137 Computed Properties 138 Motivation Behind Computed Properties 139 The newValue keyword 140 Read?]Only Computed Properties 141 Property Observers 141 Typed Properties 143 Initializers 144 Initializers and External Parameter Names 145 Initializing Variables and Constants During Initialization 147 Classes as Reference Types 147 Comparing Instances--Identity Operators 149 Comparing Instances--Equivalence Operators 150 Methods in Classes 151 Instance Methods 151 Local and External Parameter Names for Methods 152 The self Property 154 Type Methods 155 Methods in Structures 155 Summary 157 CHAPTER 9: INHERITANCE 161 Understanding Inheritance 162 Defi ning a Base Class 162 Instantiating a Base Class 162 Creating an Abstract Class 163 Inheriting from a Base Class 164 Overriding Initializers 164 Overloading Initializers 165 Creating Abstract Methods 167 Overloading Methods 169 Preventing Subclassing 170 Types of Initializers 171 Default Initializer 171 Designated Initializers 172 Convenience Initializers and Initializer Chaining 174 Calling Initializers in Subclasses 176 Extensions 177 Extending Methods 177 Extending Properties 177 Access Controls 178 Internal 179 Private 180 Public 181 Summary 181 CHAPTER 10: CLOSURES 185 Understanding Closures 186 Functions as Closures 186 Assigning Closures to Variables 187 Writing Closures Inline 188 Type Inference 188 Shorthand Argument Names 189 Operator Function 190 Trailing Closures 190 Using the Array''s Three Closure Functions 190 The map Function 191 Example 1 191 Example 2 192 The filter Function 192 Example 1 192 Example 2 193 The reduce Function 194 Example 1 194 Example 2 195 Using Closures in Your Functions 196 Summary 198 CHAPTER 11: PROTOCOLS AND DELEGATES 201 Understanding Protocols 202 Defining and Using a Protocol 202 Conforming to a Protocol 202 Optional Methods 204 Conforming to Multiple Protocols 206 Property Requirements 206 Initializer Requirements 207 Understanding Delegates 207 Delegates as Event Handlers 208 A Practical Example of Protocols and Delegates 211 Summary 213 CHAPTER 12: GENERICS 217 Understanding Generics 218 Using Generic Functions 218 Multiple Type Parameters 219 Specifying Type Constraint 220 Generic Types 221 Generic Classes 221 Generic Structures 223 Generic Type Extension 224 Using Generics in Protocols 225 Specifying Requirements for Associated Types 228 Summary 229 APPENDIX: EXERCISE ANSWERS 233 INDEX 247.