基础语法，可以直接copy到playground，看着右边结果学习用法
var total = 0
for i in 0...4 {
total += i
}
print(total)
var totalAnother = 0
for i in 0..<4 {
totalAnother += i
}
print(totalAnother)
var name = "name"
print(name)
func greet(person: String, day: String) -> String {
return "Hello \(person), today is \(day)."
}
greet(person: "Bob", day: "Tuesday")
func greet(_ person: String, on day: String) -> String {
return "Hello \(person), today is \(day)."
}
greet("John", on: "Wednesday")
func calculateStatistics(scores: [Int]) -> (min: Int, max: Int, sum: Int) {
var min = scores[0]
var max = scores[0]
var sum = 0
for score in scores {
if score > max {
max = score
} else if score < min {
min = score
}
sum += score
}
return (min, max, sum)
}
let statistics = calculateStatistics(scores: [5, 3, 100, 3, 9])
print(statistics.sum)
// Prints "120"
print(statistics.1)
func returnFifteen() -> Int {
var y = 10
func add() {
y += 5
}
add()
return y
}
returnFifteen()
func makeIncrementer() -> ((Int) -> Int) {
func addOne(number: Int) -> Int {
return 1 + number
}
return addOne
}
var increment = makeIncrementer()
increment(7)
func hasAnyMatches(list: [Int], condition: (Int) -> Bool) -> Bool {
for item in list {
if condition(item) {
return true
}
}
return false
}
func lessThanTen(number: Int) -> Bool {
return number < 10
}
var numbers = [20, 19, 7, 12]
hasAnyMatches(list: numbers, condition: lessThanTen)
numbers.map({ (number: Int) -> Int in
let result = 3 * number
return result
})
let mappedNumbers = numbers.map({ number in 2 * number })
print(mappedNumbers)
let sortedNumbers = numbers.sorted { $0 < $1 }
print(sortedNumbers)
/**/
class Shape {
var numberOfSides:Float = 0
func simpleDescription() -> String {
return "A shape with \(numberOfSides) sides."
}
}
var shape = Shape()
shape.numberOfSides = 7
var shapeDescription = shape.simpleDescription()
print(shapeDescription)
class NamedShape {
var numberOfSides: Int = 0
var name: String
var age: String?
init(name: String, age: String) {
self.name = name
self.age = age
}
func simpleDescription() -> String {
return "A shape with \(numberOfSides) sides."
}
}
var namedShape = NamedShape(name: "testName" ,age: "20")
print(namedShape.name, namedShape.age ?? "0")
class Square: NamedShape {
var sideLength: Double
init(sideLength: Double, name: String) {
self.sideLength = sideLength
super.init(name: name,age:"1")
numberOfSides = 4
}
func area() -> Double {
return sideLength * sideLength
}
override func simpleDescription() -> String {
return "A square with sides of length \(sideLength)."
}
}
let test = Square(sideLength: 5.2, name: "my test square")
test.area()
test.simpleDescription()
class EquilateralTriangle: NamedShape {
var sideLength: Double = 0.0
init(sideLength: Double, name: String) {
self.sideLength = sideLength
super.init(name: name,age:"22")
numberOfSides = 3
}
var perimeter: Double {
get {
return 3.0 * sideLength
}
set {
sideLength = newValue / 3.0
}
}
override func simpleDescription() -> String {
return "An equilateral triangle with sides of length \(sideLength)."
}
}
var triangle = EquilateralTriangle(sideLength: 3.1, name: "a triangle")
print(triangle.perimeter)
// Prints "9.3"
triangle.perimeter = 9.9
print(triangle.sideLength)
// Prints "3.3000000000000003"
enum Rank: Int {
case ace = 1
case two, three, four, five, six, seven, eight, nine, ten
case jack, queen, king
func simpleDescription() -> String {
switch self {
case .ace:
return "ace"
case .jack:
return "jack"
case .queen:
return "queen"
case .king:
return "king"
default:
return String(self.rawValue)
}
}
}
let ace = Rank.ace
let aceRawValue = ace.rawValue
let aRawValue = Rank.jack.rawValue
if let convertedRank = Rank(rawValue: 1) {
let threeDescription = convertedRank.simpleDescription()
}
enum Suit {
case spades, hearts, diamonds, clubs
func simpleDescription() -> String {
switch self {
case .spades:
return "spades"
case .hearts:
return "hearts"
case .diamonds:
return "diamonds"
case .clubs:
return "clubs"
}
}
}
let hearts = Suit.hearts
let heartsDescription = hearts.simpleDescription()
enum ServerResponse {
case result(String, String)
case failure(String)
}
let success = ServerResponse.result("6:00 am", "8:09 pm")
let failure = ServerResponse.failure("Out of cheese.")
switch success {
case let .result(sunrise, sunset):
print("Sunrise is at \(sunrise) and sunset is at \(sunset).")
case let .failure(message):
print("Failure... \(message)")
}
struct Card {
var rank: Rank
var suit: Suit
func simpleDescription() -> String {
return "The \(rank.simpleDescription()) of \(suit.simpleDescription())"
}
}
let threeOfSpades = Card(rank: .three, suit: .spades)
let threeOfSpadesDescription = threeOfSpades.simpleDescription()
public protocol ExampleProtocol {
var simpleDescription: String { get }
mutating func adjust()
}
public protocol ExampleProtocol1 {
var simpleDescription1: String { get }
mutating func adjust1()
}
class SimpleClass: ExampleProtocol,ExampleProtocol1 {
var simpleDescription1: String = "dewwf"
var simpleDescription: String = "A very simple class."
var anotherProperty: Int = 69105
func adjust() {
simpleDescription += " Now 100% adjusted."
}
func adjust1() {
simpleDescription1 += " Now 100% adjusted."
}
}
var a = SimpleClass()
a.adjust()
let aDescription = a.simpleDescription
a.adjust1()
let aDescription1 = a.simpleDescription1
struct SimpleStructure: ExampleProtocol {
var simpleDescription: String = "A simple structure"
mutating func adjust() {
simpleDescription += " (adjusted)"
}
}
var b = SimpleStructure()
b.adjust()
let bDescription = b.simpleDescription
extension Int: ExampleProtocol {
public var simpleDescription: String {
return "The number \(self)"
}
public mutating func adjust() {
self += 42
}
}
print(7.simpleDescription)
let protocolValue: ExampleProtocol = a
print(protocolValue.simpleDescription)
enum PrinterError: Error {
case outOfPaper
case noToner
case onFire
}
func send(job: Int, toPrinter printerName: String) throws -> String {
if printerName == "Never Has Toner" {
throw PrinterError.noToner
}
return "Job sent"
}
do {
let printerResponse = try send(job: 1040, toPrinter: "Never Has Toner")
print(printerResponse)
} catch {
print(error)
}
do {
let alll = 8
print(alll)
let printerResponse = try send(job: 1440, toPrinter: "Never Has Toner")
print(printerResponse)
} catch PrinterError.onFire {
print("I'll just put this over here, with the rest of the fire.")
} catch let printerError as PrinterError {
print("Printer error: \(printerError).")
} catch {
print(error)
}
let printerSuccess = try? send(job: 1884, toPrinter: "Mergenthaler")
let printerFailure = try? send(job: 1885, toPrinter: "Never Has Toner")
var fridgeIsOpen = false
let fridgeContent = ["milk", "eggs", "leftovers"]
func fridgeContains(_ food: String) -> Bool {
fridgeIsOpen = true
defer {
fridgeIsOpen = false
}
let result = fridgeContent.contains(food)
return result
}
fridgeContains("milk")
print(fridgeIsOpen)
func makeArray- (repeating item: Item, numberOfTimes: Int) -> [Item] {
var result = [Item]()
for _ in 0..
{
case none
case some(Wrapped)
}
var possibleInteger: OptionalValue = .none
possibleInteger = .some(100)
func anyCommonElements(_ lhs: D, _ rhs: U) -> Bool
where D.Element: Equatable, D.Element == U.Element
{
for lhsItem in lhs {
for rhsItem in rhs {
if lhsItem == rhsItem {
return true
}
}
}
return false
}
anyCommonElements([1, 2, 3], [3])
let tooBig: UInt8 = UInt8.max
func areTheyEqual(x: T, _ y: T) -> Bool {
return x == y
}
areTheyEqual(x:"ray", "ray")
areTheyEqual(x:1, 1)