冷市攻略:Listo 教你 25 今天的社会 Swift 语言 - 02 Swift Tour

import Foundation


//***********************************************************************************************

//1.Hello world

//_______________________________________________________________________________________________

//输出 "Hello, world"

println("Hello, world")    //使用 println 函数来输出字符串


//***********************************************************************************************

//2.Simple Values(简单值)

//_______________________________________________________________________________________________

//使用 let 命名常量,使用 var 命名变量

let myConstant =42

var myVariable =42

myVariable = 50

println("The constant is(myConstant),the variable is(myVariable)")


//_______________________________________________________________________________________________

//声明数据类型

let explicitDouble:Double = 70

println("The Double type number is(explicitDouble)")


//_______________________________________________________________________________________________

//类型转化

let label = "The width is "

let width =94

let widthLabel = label + String(width)     //不同类型数据进行基本运算的时候须要进行类型转化

println(widthLabel)


//_______________________________________________________________________________________________

//简单的字符串引用数据

let apples =3

let appleSummary ="I have (apples) apples"

println(appleSummary)


//_______________________________________________________________________________________________

//数组创建和使用

var shoppingList = ["water","bread", "milk","paper", "pen"]

println(shoppingList[2])           //获取数组中的第三个元素


//_______________________________________________________________________________________________

//字典的创建和使用

var occupations = ["Malcolm":"Captain", "Kaylee":"Mechanic"]

occupations["Jayne"] ="Public relations"      //给字典加入或者改动一个元素。系统检索字典 occupations是否包括 key Jayne,假设有进行 key 相应的 value 值的改动,假设没有,进行新的 key value 的加入

println(occupations)


//_______________________________________________________________________________________________

//创建空的数组和字典

let emptyArray = [String]()    //创建空的数组

let emptyDictionary =Dictionary<String,Float>()       //创建空的字典


//***********************************************************************************************

//3.Control Flow(控制流)

//_______________________________________________________________________________________________

//简单的控制语句

let individualScores = [75,43, 103, 87, 12]

var teamScore =0

for score inindividualScores{

   if score > 50{             //if 语句之后必须为返回一个 Bool类型的数据

       teamScore += 3

    }

   else{

       teamScore += 1

    }

}

println("The teamscore is(teamScore)")


//_______________________________________________________________________________________________

//可选类型数据

var optionalString:String?

= "Hello"

optionalString == nil       //设置 optionalString数据为可选类型数据,可选类型是指 optionalString有详细的值或者为空两种情况


var optionalName:String? = "Joho Appleseed"

var greeting ="Hello"

if let name =optionalName{        //使用 if let 来推断可选类型数据是否有详细的值

   greeting = "Hello,(name)"

}

println(greeting)


//_______________________________________________________________________________________________

//switch 语句

let vegetable ="red pepper"

var vegetableComment:String

switch vegetable{          //使用 switch 语句。每一条 case 代表一条推断。符合条件则运行语句

    case"celery":

        vegetableComment ="Add some raisins and make ants on a log."

    case"cucumber","watercress":

        vegetableComment ="That would make a good tea sandwich."

    caselet x where x.hasSuffix("pepper"):            //使用 "x.hasSuffix("***")"函数来推断 x 变量末尾是否为 ***

        vegetableComment ="Is it a spicy (x)?

"

    default:

        vegetableComment ="Everything tastes good in soup."

}

println(vegetableComment)


//_______________________________________________________________________________________________

//使用 for in

let interestingNumbers = ["Prime": [2,3, 5, 7, 11, 13],"Fibonacci": [1,1, 2, 3, 5, 8],"Square": [1,4, 9, 16, 25],]

var largest =0

for (kind, numbers)in interestingNumbers{

   for number in numbers{

       if number > largest{

           largest = number

        }

    }

}

println("The largest number is(largest)")


//_______________________________________________________________________________________________

//使用 while do while 语句

var n =2

whilen < 100{

   n = n * 2

}

println("the n is(n)")


var m =2

do{

   m = m * 2

}while m < 100

println("the m is(m)")


//_______________________________________________________________________________________________

//范围运算符

var firstForLoop =0

for iin 0..<4{            //使用 "..<"表示前闭后开范围

    firstForLoop += i

}

println("firstForLoop is(firstForLoop)")


var secondForLoop =0

forvar i = 0; i <4; ++i{      //使用一般方法进行运算

    secondForLoop += i

}

println("secondForLoop is(secondForLoop)")


var thirdForLoop =0

for iin 0...4{            //使用 "..."表示前闭后闭范围

    thirdForLoop += i

}

println("thirdForLoop is(thirdForLoop)")


//***********************************************************************************************

//4.Function and Closures(函数和闭包)

//_______________________________________________________________________________________________

//函数的创建和使用

func greet(name: String, day: String) -> String{        //使用 "func 函数名(參数) -> 返回值类型{ return *** }" 来创建一个函数

    return"Hello (name), today is (day)"

}

println(greet("Bob","Tusday"))


//_______________________________________________________________________________________________

//无參数的函数

func getGasPrices() -> (Double,Double, Double){       //函数參数为空

    return (3.59,3.69, 3.79)

}

println(getGasPrices())


//_______________________________________________________________________________________________

//不确定參数的函数

func sumOf(numbers:Int...) -> Int{        //当函数參数不确定数量的时候,使用 "..."就可以

   var sum = 0

   for number in numbers{

        sum += number

    }

   return sum

}

println(sumOf(234,34,12))


//_______________________________________________________________________________________________

//函数嵌套

func returnFifteen() ->Int{

   var y = 10

   func add(){

        y +=5

    }

   add()

   return y

}

println(returnFifteen())


//_______________________________________________________________________________________________

//函数作为返回值

func makeIncrementer() -> (Int ->Int){     //定义返回值为函数类型的函数 makeIncrementer

   func addOne(number: Int) -> Int{

       return 1 + number

    }

    return addOne

}

var increment =makeIncrementer()

println(increment(7))


//_______________________________________________________________________________________________

//函数做參数

func hasAnyMatches(list: [Int], condition:Int ->Bool) -> Bool{    //设置參数为整型数组和函数类型的函数 hasAnyMatches

   for item in list{

       if condition(item){

           return true

        }

    }

    return false

}

func lessThanTen(number:Int) -> Bool{     //定义函数符合 hasAnyMatches的參数类型

   return number < 10

}

var numbers = [20,19, 7, 12]

println(hasAnyMatches(numbers,lessThanTen))


//_______________________________________________________________________________________________

//闭包

var numberArray = [3,45, 23, 523, 2]

let number =numberArray.map({           //Swift 中的 Array中有一个 map 方法。其获取的一个闭包表达式作为其唯一參数,数组中的每个元素调用次该闭包函数。并返回该元素所映射的值,详细的映射方式和返回值类型由闭包来指定

    (number:Int) -> Int in

   let result = 3 * number

   return result

})

println(number)


//***********************************************************************************************

//5.Objects and Classes(对象和类)

//_______________________________________________________________________________________________

//类的创建

class Shape{               //使用 class声明一个类,类中的属性声明和声明常量变量一样。方法和函数声明是同样的方式

   var numberOfSides = 0

   func simpleDescription() -> String{

        return"A shape with (numberOfSides) sides."

    }

}


//_______________________________________________________________________________________________

//使用类

var shape = Shape()     //实例化一个类。注意类名首字母大写

shape.numberOfSides =7         //设置类的属性

var shapeDescription =shape.simpleDescription()       //訪问类的方法

println(shapeDescription)


//_______________________________________________________________________________________________

//使用 init 创建一个类的初始化器

class NamedShape{

   var numberOfSides: Int = 0

   var name: String

    

   init(name: String){

        self.name = name       //self 用来区分属性和參数,在初始化这个类时,每一个初始值必须设置

    }

    

   func simpleDescription() -> String{

        return"(name) find A shape with(numberOfSides) sides."

    }

}

var name = NamedShape(name: "Listo")     //实例化而且初始化类 NameShape

name.numberOfSides =7

var nameDescription =name.simpleDescription()

println(nameDescription)


//_______________________________________________________________________________________________

//继承和覆写

class Square:NamedShape{

   var sideLength: Double

    

   init(sideLength: Double, name:String){

       self.sideLength = sideLength

       super.init(name: name)

        numberOfSides =4

    }

    

   func area() -> Double{

        returnsideLength * sideLength

    }

    

   override func simpleDescription() ->String {           //使用 override来覆写父类中的方法

        return"A square with sides of length (sideLength)"

    }

}

let test =Square(sideLength:  5.2, name: "my test square")

println(test.area())

println(test.simpleDescription())


//_______________________________________________________________________________________________

//除了简单的存储属性。属性能够有一个 getter setter

class EquilateralTriangle:NamedShape{

   var sideLength: Double =0.0

    

   init(sideLength: Double, name:String){

       self.sideLength = sideLength

       super.init(name: name)

        numberOfSides =3

    }

    

   var perimeter: Double{

   get{

       return 3.0 *sideLength             //get 为获取这个属性的值

    }

   set{

       sideLength = newValue / 3.0         //newValue 代表 set给这个属性的新的值

    }

    }

    

   override func simpleDescription() ->String {

        return"An equilateral triangle with side of length (sideLength)"

    }

}

var triangle =EquilateralTriangle(sideLength: 3.1, name: "a triangle")

println(triangle.perimeter)

triangle.perimeter =9.9

println(triangle.sideLength)


//_______________________________________________________________________________________________

//类中的方法和函数的差别

class Counter{

   var count: Int =0

   func incrementBy(amount: Int, numberOfTimes times: Int){

       count += amount * times

    }

}

var counter =Counter()

counter.incrementBy(2, numberOfTimes: 7)       //类中的方法须要在调用的时候写出參数的形參名(第一个參数名不能够写),函数在调用的时候除了外部參数存在的情况,否则不能參数的形參名


//***********************************************************************************************

//6.Enumeration and Structures(枚举和结构体)

//_______________________________________________________________________________________________

//枚举的创建

enum Rank: Int{         //使用 enum 创建一个枚举,注意枚举名用大写

    case Ace =1        //指定第一个原始值为 1,后面的数据一次递增分配

   case Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten

   case Jack, Queen, King

   func simpleDescription() -> String{

        switchself{       //这里的 self 就是一个枚举类型的值(enum value

       case .Ace:

           return "ace"

       case .Jack:

           return "jack"

       case .Queen:

           return "queen"

       case .King:

           return "king"

       default:

            returnString(self.toRaw())    //使用 toRaw fromRaw 来实现原始值和枚举值的转换

        }

    }

}

let ace =Rank.Ace

println(ace.simpleDescription())

let aceRawValue =ace.toRaw()

println(aceRawValue)


iflet convertedRank = Rank.fromRaw(3){

   let threeDescription = convertedRank.simpleDescription()

   println(threeDescription)

}


//_______________________________________________________________________________________________

//枚举成员是实际的值,不是其原始值的第二种表达方式

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 heartDescription =hearts.simpleDescription()

println(heartDescription)


//_______________________________________________________________________________________________

//结构体的创建(结构体和类之间最重要的一个差别是,结构体通过复制传递。类通过引用传递)

struct Card{       //创建结构体,结构体名大写

   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()

println(threeOfSpadesDescription)


//_______________________________________________________________________________________________

//枚举的应用

enum ServerResponse{

   case Result(String, String)

   case Error(String)

}


let success = ServerResponse.Result("6:00 am","8:09 pm")

let failure = ServerResponse.Error("Out of cheese")


var serverResonse:String

switch success{

caselet .Result(sunrise, sunset):

    serverResonse ="Sunrise is at (sunrise) and sunset is at(sunset)"

caselet .Error(error):

   serverResonse = "Failure...(error)"

}

println(serverResonse)


//***********************************************************************************************

//7.Protocols and Extensions(协议和扩展)

//_______________________________________________________________________________________________

//协议的创建

protocol ExamplePortocol{      //使用 protocol 创建协议,协议名要大写

   var simpleDescription: String { get}

   mutating func adjust()

}


//_______________________________________________________________________________________________

//类,枚举,结构体都能够写协议

class SimpleClass:ExamplePortocol{             //类遵守协议。必须实现协议中的方法

   var simpleDescription: String = "A very simple class."

   var anotherProperty: Int = 69105

   func adjust(){                              //在类中书写协议方法是不须要加上 mutating,由于一个类的方法能够改动类

        simpleDescription +=" Now 100% adjusted."

    }

}

var a = SimpleClass()

a.adjust()

let aDescription =a.simpleDescription

println(aDescription)


struct SimpleStructure:ExamplePortocol{        //结构体遵守协议。必须实现协议中的方法

   var simpleDescription: String = "A simple structure"

   mutating  func adjust() {                  //在结构体中书写协议方法时要记得加上 mutating

        simpleDescription +=" (adjusted)"

    }

}

var b = SimpleStructure()

b.adjust()

println(b.simpleDescription)


//_______________________________________________________________________________________________

//使用 extension将扩展功能加入到现有的类型中

extensionInt: ExamplePortocol{            //为协议加入功能

   var simpleDescription: String{

    return"The number (self)"

    }

   mutating func adjust(){

       self += 42

    }

}


//_______________________________________________________________________________________________

//使用协议作为数据类型

let protocolValue:ExamplePortocol = a

println(protocolValue.simpleDescription)


//***********************************************************************************************

//8.Generics(通用数据类型)

//_______________________________________________________________________________________________

//尖括号内写一个名字做一个通用的函数或类型

func repeat<ItemType>(item:ItemType, times: Int) -> [ItemType] {      //做通用的类型

   var result = [ItemType]()

   for i in 0..<times{

        result += item

    }

   return result

}

println(repeat("Knock",4))


//_______________________________________________________________________________________________

//你能够通用形式的函数和方法,以及类、枚举、结构

enum OptionalValue<T>{

   case None

   case some(T)

}

var possibleInteger:OptionalValue<Int> = .None

possibleInteger = .some(100)

println(possibleInteger)

原文地址:https://www.cnblogs.com/lcchuguo/p/5032494.html