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- update Swift examples
- update to upgrade to Swift 2.1 - code cleanup
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@ -32,7 +32,7 @@ import UIKit
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// In Swift 2, println and print were combined into one print method. Print automatically appends a new line.
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print("Hello, world") // println is now print
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print("Hello, world", appendNewLine: false) // printing without appending a newline
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print("Hello, world", terminator: "") // printing without appending a newline
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// variables (var) value can change after being set
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// constants (let) value can NOT be changed after being set
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@ -60,14 +60,14 @@ let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation
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print("Build value: \(buildValue)") // Build value: 7
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/*
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Optionals are a Swift language feature that either contains a value,
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or contains nil (no value) to indicate that a value is missing.
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A question mark (?) after the type marks the value as optional.
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Optionals are a Swift language feature that either contains a value,
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or contains nil (no value) to indicate that a value is missing.
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A question mark (?) after the type marks the value as optional.
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Because Swift requires every property to have a value, even nil must be
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explicitly stored as an Optional value.
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Because Swift requires every property to have a value, even nil must be
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explicitly stored as an Optional value.
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Optional<T> is an enum.
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Optional<T> is an enum.
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*/
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var someOptionalString: String? = "optional" // Can be nil
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// same as above, but ? is a postfix operator (syntax candy)
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@ -84,9 +84,9 @@ if someOptionalString != nil {
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someOptionalString = nil
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/*
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Trying to use ! to access a non-existent optional value triggers a runtime
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error. Always make sure that an optional contains a non-nil value before
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using ! to force-unwrap its value.
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Trying to use ! to access a non-existent optional value triggers a runtime
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error. Always make sure that an optional contains a non-nil value before
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using ! to force-unwrap its value.
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*/
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// implicitly unwrapped optional
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@ -120,8 +120,8 @@ anyObjectVar = "Changed value to a string, not good practice, but possible."
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//
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/*
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Array and Dictionary types are structs. So `let` and `var` also indicate
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that they are mutable (var) or immutable (let) when declaring these types.
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Array and Dictionary types are structs. So `let` and `var` also indicate
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that they are mutable (var) or immutable (let) when declaring these types.
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*/
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// Array
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@ -178,8 +178,8 @@ while i < 1000 {
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i *= 2
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}
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// do-while loop
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do {
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// repeat-while loop
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repeat {
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print("hello")
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} while 1 == 2
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@ -209,22 +209,22 @@ default: // required (in order to cover all possible input)
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// Function with Swift header docs (format as reStructedText)
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/**
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A greet operation
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A greet operation
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- A bullet in docs
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- Another bullet in the docs
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- A bullet in docs
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- Another bullet in the docs
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:param: name A name
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:param: day A day
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:returns: A string containing the name and day value.
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:param: name A name
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:param: day A day
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:returns: A string containing the name and day value.
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*/
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func greet(name: String, day: String) -> String {
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return "Hello \(name), today is \(day)."
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}
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greet("Bob", "Tuesday")
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greet("Bob", day: "Tuesday")
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// similar to above except for the function parameter behaviors
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func greet2(#requiredName: String, externalParamName localParamName: String) -> String {
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func greet2(requiredName requiredName: String, externalParamName localParamName: String) -> String {
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return "Hello \(requiredName), the day is \(localParamName)"
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}
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greet2(requiredName: "John", externalParamName: "Sunday")
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@ -247,14 +247,14 @@ func getGasPrices2() -> (lowestPrice: Double, highestPrice: Double, midPrice: Do
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let pricesTuple2 = getGasPrices2()
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let price2 = pricesTuple2.lowestPrice
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let (_, price3, _) = pricesTuple2
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println(pricesTuple2.highestPrice == pricesTuple2.1) // true
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println("Highest gas price: \(pricesTuple2.highestPrice)")
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print(pricesTuple2.highestPrice == pricesTuple2.1) // true
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print("Highest gas price: \(pricesTuple2.highestPrice)")
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// Variadic Args
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func setup(numbers: Int...) {
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// its an array
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let number = numbers[0]
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let argCount = numbers.count
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let _ = numbers[0]
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let _ = numbers.count
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}
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// Passing and returning functions
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@ -275,7 +275,7 @@ func swapTwoInts(inout a: Int, inout b: Int) {
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}
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var someIntA = 7
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var someIntB = 3
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swapTwoInts(&someIntA, &someIntB)
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swapTwoInts(&someIntA, b: &someIntB)
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print(someIntB) // 7
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@ -303,23 +303,17 @@ numbers = numbers.map({ number in 3 * number })
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print(numbers) // [3, 6, 18]
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// Trailing closure
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numbers = sorted(numbers) { $0 > $1 }
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numbers = numbers.sort { $0 > $1 }
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print(numbers) // [18, 6, 3]
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// Super shorthand, since the < operator infers the types
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numbers = sorted(numbers, < )
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print(numbers) // [3, 6, 18]
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//
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// MARK: Structures
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//
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// Structures and classes have very similar capabilities
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struct NamesTable {
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let names = [String]()
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let names: [String]
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// Custom subscript
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subscript(index: Int) -> String {
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@ -472,9 +466,10 @@ enum Suit {
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// when the variable is explicitly declared
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var suitValue: Suit = .Hearts
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// Non-Integer enums require direct raw value assignments
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// String enums can have direct raw value assignments
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// or their raw values will be derived from the Enum field
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enum BookName: String {
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case John = "John"
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case John
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case Luke = "Luke"
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}
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print("Name: \(BookName.John.rawValue)")
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@ -518,7 +513,7 @@ protocol ShapeGenerator {
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// Protocols declared with @objc allow optional functions,
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// which allow you to check for conformance
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@objc protocol TransformShape {
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optional func reshaped()
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optional func reshape()
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optional func canReshape() -> Bool
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}
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@ -531,9 +526,9 @@ class MyShape: Rect {
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// Place a question mark after an optional property, method, or
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// subscript to gracefully ignore a nil value and return nil
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// instead of throwing a runtime error ("optional chaining").
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if let allow = self.delegate?.canReshape?() {
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if let reshape = self.delegate?.canReshape?() where reshape {
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// test for delegate then for method
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self.delegate?.reshaped?()
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self.delegate?.reshape?()
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}
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}
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}
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@ -546,7 +541,7 @@ class MyShape: Rect {
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// `extension`s: Add extra functionality to an already existing type
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// Square now "conforms" to the `Printable` protocol
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extension Square: Printable {
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extension Square: CustomStringConvertible {
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var description: String {
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return "Area: \(self.getArea()) - ID: \(self.identifier)"
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}
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@ -571,8 +566,8 @@ print(14.multiplyBy(3)) // 42
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// Generics: Similar to Java and C#. Use the `where` keyword to specify the
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// requirements of the generics.
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func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? {
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for (index, value) in enumerate(array) {
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func findIndex<T: Equatable>(array: [T], _ valueToFind: T) -> Int? {
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for (index, value) in array.enumerate() {
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if value == valueToFind {
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return index
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}
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