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mirror of https://github.com/adambard/learnxinyminutes-docs.git synced 2025-08-13 18:24:39 +02:00

- mo betta examples

- add `inout` example
- better `optional` example
- Playground issue has been resolved, uncommented `protocol` example
This commit is contained in:
C. Bess
2014-10-04 12:08:23 -05:00
parent c77c92818c
commit 923a8ed99b

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@@ -13,6 +13,9 @@ The official [Swift Programming Language](https://itunes.apple.com/us/book/swift
See also Apple's [getting started guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/LandingPage/index.html), which has a complete tutorial on Swift. See also Apple's [getting started guide](https://developer.apple.com/library/prerelease/ios/referencelibrary/GettingStarted/LandingPage/index.html), which has a complete tutorial on Swift.
```swift ```swift
// import a module
import UIKit
// //
// MARK: Basics // MARK: Basics
// //
@@ -26,7 +29,7 @@ println("Hello, world")
var myVariable = 42 var myVariable = 42
let øπΩ = "value" // unicode variable names let øπΩ = "value" // unicode variable names
let myConstant = 3.1415926 let π = 3.1415926
let convenience = "keyword" // contextual variable name let convenience = "keyword" // contextual variable name
let weak = "keyword"; let override = "another keyword" // statements can be separated by a semi-colon let weak = "keyword"; let override = "another keyword" // statements can be separated by a semi-colon
let `class` = "keyword" // backticks allow keywords to be used as variable names let `class` = "keyword" // backticks allow keywords to be used as variable names
@@ -34,9 +37,24 @@ let explicitDouble: Double = 70
let intValue = 0007 // 7 let intValue = 0007 // 7
let largeIntValue = 77_000 // 77000 let largeIntValue = 77_000 // 77000
let label = "some text " + String(myVariable) // Casting let label = "some text " + String(myVariable) // Casting
let piText = "Pi = \(myConstant), Pi 2 = \(myConstant * 2)" // String interpolation let piText = "Pi = \(π), Pi 2 = \(π * 2)" // String interpolation
var optionalString: String? = "optional" // Can be nil var someOptionalString: String? = "optional" // Can be nil
optionalString = nil
if someOptionalString != nil {
// I am not nil
if someOptionalString!.hasPrefix("opt") {
println("has the prefix")
}
let empty = someOptionalString?.isEmpty
}
someOptionalString = nil
if let someStringConstant = someOptionalString {
// has Some value
}
// AnyObject == id
/* /*
Comment here Comment here
@@ -84,9 +102,10 @@ for (key, value) in dict {
} }
// for loop (range) // for loop (range)
for i in -1...1 { // [-1, 0, 1] for i in -1...shoppingList.count {
println(i) println(i)
} }
shoppingList[1...2] = ["steak", "peacons"]
// use ..< to exclude the last number // use ..< to exclude the last number
// while loop // while loop
@@ -141,9 +160,16 @@ greet("Bob", "Tuesday")
func getGasPrices() -> (Double, Double, Double) { func getGasPrices() -> (Double, Double, Double) {
return (3.59, 3.69, 3.79) return (3.59, 3.69, 3.79)
} }
let pricesTuple = getGasPrices()
let price = pricesTuple.2 // 3.79
println("Gas price: \(price)")
// Variadic Args // Variadic Args
func setup(numbers: Int...) {} func setup(numbers: Int...) {
// its an array
let number = numbers[0]
let argCount = numbers.count
}
// Passing and returning functions // Passing and returning functions
func makeIncrementer() -> (Int -> Int) { func makeIncrementer() -> (Int -> Int) {
@@ -155,6 +181,17 @@ func makeIncrementer() -> (Int -> Int) {
var increment = makeIncrementer() var increment = makeIncrementer()
increment(7) increment(7)
// pass by ref
func swapTwoInts(inout a: Int, inout b: Int) {
let tempA = a
a = b
b = tempA
}
var someIntA = 7
var someIntB = 3
swapTwoInts(&someIntA, &someIntB)
println(someIntB) // 7
// //
// MARK: Closures // MARK: Closures
@@ -255,8 +292,9 @@ internal class Rect: Shape {
} }
init(sideLength: Int) { init(sideLength: Int) {
super.init()
self.sideLength = sideLength self.sideLength = sideLength
// always super.init last when init custom properties
super.init()
} }
func shrink() { func shrink() {
@@ -321,7 +359,6 @@ protocol ShapeGenerator {
func buildShape() -> Shape func buildShape() -> Shape
} }
/*
// Protocols declared with @objc allow optional functions, // Protocols declared with @objc allow optional functions,
// which allow you to check for conformance // which allow you to check for conformance
@objc protocol TransformShape { @objc protocol TransformShape {
@@ -341,7 +378,7 @@ class MyShape: Rect {
} }
} }
} }
*/
// //
// MARK: Other // MARK: Other
@@ -372,7 +409,7 @@ extension Int {
println(7.customProperty) // "This is 7" println(7.customProperty) // "This is 7"
println(14.multiplyBy(2)) // 42 println(14.multiplyBy(2)) // 42
// Generics: Similar to Java. Use the `where` keyword to specify the // Generics: Similar to Java and C#. Use the `where` keyword to specify the
// requirements of the generics. // requirements of the generics.
func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? { func findIndex<T: Equatable>(array: [T], valueToFind: T) -> Int? {