diff options
Diffstat (limited to 'swift.html.markdown')
| -rw-r--r-- | swift.html.markdown | 97 |
1 files changed, 76 insertions, 21 deletions
diff --git a/swift.html.markdown b/swift.html.markdown index 0977efc4..509c9d2f 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -3,6 +3,8 @@ language: swift contributors: - ["Grant Timmerman", "http://github.com/grant"] - ["Christopher Bess", "http://github.com/cbess"] + - ["Joey Huang", "http://github.com/kamidox"] + - ["Anthony Nguyen", "http://github.com/anthonyn60"] filename: learnswift.swift --- @@ -25,7 +27,9 @@ import UIKit // TODO: Do something soon // FIXME: Fix this code -println("Hello, world") +// In Swift 2, println and print were combined into one print method. Print automatically appends a new line. +print("Hello, world") // println is now print +print("Hello, world", appendNewLine: false) // printing without appending a newline // variables (var) value can change after being set // constants (let) value can NOT be changed after being set @@ -45,12 +49,12 @@ let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation // Build Specific values // uses -D build configuration #if false - println("Not printed") + print("Not printed") let buildValue = 3 #else let buildValue = 7 #endif -println("Build value: \(buildValue)") // Build value: 7 +print("Build value: \(buildValue)") // Build value: 7 /* Optionals are a Swift language feature that allows you to store a `Some` or @@ -68,7 +72,7 @@ var someOptionalString2: Optional<String> = "optional" if someOptionalString != nil { // I am not nil if someOptionalString!.hasPrefix("opt") { - println("has the prefix") + print("has the prefix") } let empty = someOptionalString?.isEmpty @@ -137,21 +141,21 @@ var emptyMutableDictionary = [String: Float]() // var == mutable let myArray = [1, 1, 2, 3, 5] for value in myArray { if value == 1 { - println("One!") + print("One!") } else { - println("Not one!") + print("Not one!") } } // for loop (dictionary) var dict = ["one": 1, "two": 2] for (key, value) in dict { - println("\(key): \(value)") + print("\(key): \(value)") } // for loop (range) for i in -1...shoppingList.count { - println(i) + print(i) } shoppingList[1...2] = ["steak", "peacons"] // use ..< to exclude the last number @@ -164,7 +168,7 @@ while i < 1000 { // do-while loop do { - println("hello") + print("hello") } while 1 == 2 // Switch @@ -221,8 +225,8 @@ let pricesTuple = getGasPrices() let price = pricesTuple.2 // 3.79 // Ignore Tuple (or other) values by using _ (underscore) let (_, price1, _) = pricesTuple // price1 == 3.69 -println(price1 == pricesTuple.1) // true -println("Gas price: \(price)") +print(price1 == pricesTuple.1) // true +print("Gas price: \(price)") // Variadic Args func setup(numbers: Int...) { @@ -250,7 +254,7 @@ func swapTwoInts(inout a: Int, inout b: Int) { var someIntA = 7 var someIntB = 3 swapTwoInts(&someIntA, &someIntB) -println(someIntB) // 7 +print(someIntB) // 7 // @@ -304,7 +308,7 @@ struct NamesTable { // Structures have an auto-generated (implicit) designated initializer let namesTable = NamesTable(names: ["Me", "Them"]) let name = namesTable[1] -println("Name is \(name)") // Name is Them +print("Name is \(name)") // Name is Them // // MARK: Classes @@ -385,7 +389,36 @@ let aShape = mySquare as Shape // compare instances, not the same as == which compares objects (equal to) if mySquare === mySquare { - println("Yep, it's mySquare") + print("Yep, it's mySquare") +} + +// Optional init +class Circle: Shape { + var radius: Int + override func getArea() -> Int { + return 3 * radius * radius + } + + // Place a question mark postfix after `init` is an optional init + // which can return nil + init?(radius: Int) { + self.radius = radius + super.init() + + if radius <= 0 { + return nil + } + } +} + +var myCircle = Circle(radius: 1) +print(myCircle?.getArea()) // Optional(3) +print(myCircle!.getArea()) // 3 +var myEmptyCircle = Circle(radius: -1) +print(myEmptyCircle?.getArea()) // "nil" +if let circle = myEmptyCircle { + // will not execute since myEmptyCircle is nil + print("circle is not nil") } @@ -417,7 +450,29 @@ enum BookName: String { case John = "John" case Luke = "Luke" } -println("Name: \(BookName.John.rawValue)") +print("Name: \(BookName.John.rawValue)") + +// Enum with associated Values +enum Furniture { + // Associate with Int + case Desk(height: Int) + // Associate with String and Int + case Chair(String, Int) + + func description() -> String { + switch self { + case .Desk(let height): + return "Desk with \(height) cm" + case .Chair(let brand, let height): + return "Chair of \(brand) with \(height) cm" + } + } +} + +var desk: Furniture = .Desk(height: 80) +print(desk.description()) // "Desk with 80 cm" +var chair = Furniture.Chair("Foo", 40) +print(chair.description()) // "Chair of Foo with 40 cm" // @@ -470,7 +525,7 @@ extension Square: Printable { } } -println("Square: \(mySquare)") +print("Square: \(mySquare)") // You can also extend built-in types extension Int { @@ -483,8 +538,8 @@ extension Int { } } -println(7.customProperty) // "This is 7" -println(14.multiplyBy(3)) // 42 +print(7.customProperty) // "This is 7" +print(14.multiplyBy(3)) // 42 // Generics: Similar to Java and C#. Use the `where` keyword to specify the // requirements of the generics. @@ -498,7 +553,7 @@ func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? { return nil } let foundAtIndex = findIndex([1, 2, 3, 4], 3) -println(foundAtIndex == 2) // true +print(foundAtIndex == 2) // true // Operators: // Custom operators can start with the characters: @@ -514,9 +569,9 @@ prefix func !!! (inout shape: Square) -> Square { } // current value -println(mySquare.sideLength) // 4 +print(mySquare.sideLength) // 4 // change side length using custom !!! operator, increases size by 3 !!!mySquare -println(mySquare.sideLength) // 12 +print(mySquare.sideLength) // 12 ``` |