diff options
author | C. Bess <cbess@company.com> | 2015-11-09 18:09:48 -0600 |
---|---|---|
committer | C. Bess <cbess@company.com> | 2015-11-09 18:09:48 -0600 |
commit | 618f8f5badfded04ee1edb7c24ccf24ea61a947b (patch) | |
tree | 997b87d12347df6c7d2b01e74011a074cc5ad6c7 /swift.html.markdown | |
parent | df0992d72c2a28f140e6ff9681c505f36e19249a (diff) |
- update Swift examples
- update to upgrade to Swift 2.1
- code cleanup
Diffstat (limited to 'swift.html.markdown')
-rw-r--r-- | swift.html.markdown | 81 |
1 files changed, 38 insertions, 43 deletions
diff --git a/swift.html.markdown b/swift.html.markdown index f2e9d04c..a39bc1d6 100644 --- a/swift.html.markdown +++ b/swift.html.markdown @@ -32,7 +32,7 @@ import UIKit // 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 +print("Hello, world", terminator: "") // printing without appending a newline // variables (var) value can change after being set // constants (let) value can NOT be changed after being set @@ -60,14 +60,14 @@ let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation print("Build value: \(buildValue)") // Build value: 7 /* - Optionals are a Swift language feature that either contains a value, - or contains nil (no value) to indicate that a value is missing. - A question mark (?) after the type marks the value as optional. +Optionals are a Swift language feature that either contains a value, +or contains nil (no value) to indicate that a value is missing. +A question mark (?) after the type marks the value as optional. - Because Swift requires every property to have a value, even nil must be - explicitly stored as an Optional value. +Because Swift requires every property to have a value, even nil must be +explicitly stored as an Optional value. - Optional<T> is an enum. +Optional<T> is an enum. */ var someOptionalString: String? = "optional" // Can be nil // same as above, but ? is a postfix operator (syntax candy) @@ -84,9 +84,9 @@ if someOptionalString != nil { someOptionalString = nil /* - Trying to use ! to access a non-existent optional value triggers a runtime - error. Always make sure that an optional contains a non-nil value before - using ! to force-unwrap its value. +Trying to use ! to access a non-existent optional value triggers a runtime +error. Always make sure that an optional contains a non-nil value before +using ! to force-unwrap its value. */ // implicitly unwrapped optional @@ -120,8 +120,8 @@ anyObjectVar = "Changed value to a string, not good practice, but possible." // /* - Array and Dictionary types are structs. So `let` and `var` also indicate - that they are mutable (var) or immutable (let) when declaring these types. +Array and Dictionary types are structs. So `let` and `var` also indicate +that they are mutable (var) or immutable (let) when declaring these types. */ // Array @@ -178,8 +178,8 @@ while i < 1000 { i *= 2 } -// do-while loop -do { +// repeat-while loop +repeat { print("hello") } while 1 == 2 @@ -209,22 +209,22 @@ default: // required (in order to cover all possible input) // Function with Swift header docs (format as reStructedText) /** - A greet operation +A greet operation - - A bullet in docs - - Another bullet in the docs +- A bullet in docs +- Another bullet in the docs - :param: name A name - :param: day A day - :returns: A string containing the name and day value. +:param: name A name +:param: day A day +:returns: A string containing the name and day value. */ func greet(name: String, day: String) -> String { return "Hello \(name), today is \(day)." } -greet("Bob", "Tuesday") +greet("Bob", day: "Tuesday") // similar to above except for the function parameter behaviors -func greet2(#requiredName: String, externalParamName localParamName: String) -> String { +func greet2(requiredName requiredName: String, externalParamName localParamName: String) -> String { return "Hello \(requiredName), the day is \(localParamName)" } greet2(requiredName: "John", externalParamName: "Sunday") @@ -247,14 +247,14 @@ func getGasPrices2() -> (lowestPrice: Double, highestPrice: Double, midPrice: Do let pricesTuple2 = getGasPrices2() let price2 = pricesTuple2.lowestPrice let (_, price3, _) = pricesTuple2 -println(pricesTuple2.highestPrice == pricesTuple2.1) // true -println("Highest gas price: \(pricesTuple2.highestPrice)") +print(pricesTuple2.highestPrice == pricesTuple2.1) // true +print("Highest gas price: \(pricesTuple2.highestPrice)") // Variadic Args func setup(numbers: Int...) { // its an array - let number = numbers[0] - let argCount = numbers.count + let _ = numbers[0] + let _ = numbers.count } // Passing and returning functions @@ -275,7 +275,7 @@ func swapTwoInts(inout a: Int, inout b: Int) { } var someIntA = 7 var someIntB = 3 -swapTwoInts(&someIntA, &someIntB) +swapTwoInts(&someIntA, b: &someIntB) print(someIntB) // 7 @@ -303,23 +303,17 @@ numbers = numbers.map({ number in 3 * number }) print(numbers) // [3, 6, 18] // Trailing closure -numbers = sorted(numbers) { $0 > $1 } +numbers = numbers.sort { $0 > $1 } print(numbers) // [18, 6, 3] -// Super shorthand, since the < operator infers the types - -numbers = sorted(numbers, < ) - -print(numbers) // [3, 6, 18] - // // MARK: Structures // // Structures and classes have very similar capabilities struct NamesTable { - let names = [String]() + let names: [String] // Custom subscript subscript(index: Int) -> String { @@ -472,9 +466,10 @@ enum Suit { // when the variable is explicitly declared var suitValue: Suit = .Hearts -// Non-Integer enums require direct raw value assignments +// String enums can have direct raw value assignments +// or their raw values will be derived from the Enum field enum BookName: String { - case John = "John" + case John case Luke = "Luke" } print("Name: \(BookName.John.rawValue)") @@ -518,7 +513,7 @@ protocol ShapeGenerator { // Protocols declared with @objc allow optional functions, // which allow you to check for conformance @objc protocol TransformShape { - optional func reshaped() + optional func reshape() optional func canReshape() -> Bool } @@ -531,9 +526,9 @@ class MyShape: Rect { // Place a question mark after an optional property, method, or // subscript to gracefully ignore a nil value and return nil // instead of throwing a runtime error ("optional chaining"). - if let allow = self.delegate?.canReshape?() { + if let reshape = self.delegate?.canReshape?() where reshape { // test for delegate then for method - self.delegate?.reshaped?() + self.delegate?.reshape?() } } } @@ -546,7 +541,7 @@ class MyShape: Rect { // `extension`s: Add extra functionality to an already existing type // Square now "conforms" to the `Printable` protocol -extension Square: Printable { +extension Square: CustomStringConvertible { var description: String { return "Area: \(self.getArea()) - ID: \(self.identifier)" } @@ -571,8 +566,8 @@ print(14.multiplyBy(3)) // 42 // Generics: Similar to Java and C#. Use the `where` keyword to specify the // requirements of the generics. -func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? { - for (index, value) in enumerate(array) { +func findIndex<T: Equatable>(array: [T], _ valueToFind: T) -> Int? { + for (index, value) in array.enumerate() { if value == valueToFind { return index } |