SwiftBasicSyntax-Learn Swift(First Day)

Apple had released Swift for almost 2 years, and recently they openSource swift 2.0. As an iOS developer, I thought it’s necessary to get in touch with swift. After busy working, I make sometime to learn it.

First, create a playground, and according Apple document, start learn some basic syntax, here is the new feature i’ve learned.

import UIKit

var str = "Hello, World"

//************常量************
let constValue = 12

//************变量************
var variableValue = 10
variableValue = 11
variableValue

//初始值没有初始化,需要声明类型
let explictDouble : Double = 70

//practice
let myFloat : Float = 4


//************类型转换*********
let label = "The width is"
let width = 94

//转换一
let widthLabel = label + String(width)
//转换二
let widthLabelTwo = label + "\(width)"


//**************字典和数组************
var shoppingList = ["fish","rice","milk","meat"]
shoppingList[1]

var alexPersonInfo = [
    "name":"alex",
    "age":"24"
]
alexPersonInfo["name"]
alexPersonInfo["age"]

let emptyArray = [String]()
let emptyDictionary = Dictionary<String,Float>()

//****************控制流**************
let individualScore = [33,44,55,66,77]
var teamScore = 0
for score in individualScore{
    if score > 50{
        teamScore += 3
    }else{
        teamScore += 1
    }
}
teamScore

//可选值使用 "?" 表示
var optionalString : String? = "Hello"
optionalString == nil

var optionalName : String? = "John Appleseed"
var greeting = "Hello!"

if let name = optionalName{
    greeting = "Hello + \(name)"
}

//*************switch 支持各种类型的比较**************
let vegetable = "red pepper"
switch vegetable{
case "celery":
    let vegetableComment = "1"
case "cucumber","watermelon":
    let vegetableComment = "2"
case let x where x.hasPrefix("pepper"):
    let vegetableComment = "3"
default:
    let vegetableComment = "default"
}

//*****************for-in*************************
let interestingNumbers = [
    "Prime":[2,3,5,7,11,13],
    "Fibonacci":[1,1,2,3,5,8],
    "Square":[1,4,9,16,25,36],
]

var largest = 0
for (kind,numbers) in interestingNumbers{
    for number in numbers{
        if number > largest{
            largest = number
        }
    }
}
largest

var firstForLoop  = 0
for i in 0 ... 10{
    firstForLoop = firstForLoop + i
}
firstForLoop

//********************while && repeat-while*************

var n = 2
while n < 100 {
    n = n * 2
}
n



var m = 2
repeat{
    m = m  * 2
}while m < 100
m



//*************控制转移********************************

// continue,和之前相同
// break,和之前相同
// fallthrough,由于Swift中case后没有break,此处的fallthough就相当于break
// return 和之前相同



//***********************函数和闭包**********************
func greet(name: String, day: String) -> String{
    return "Hello \(name), today is \(day)"
}
greet("ALex", day: "Tuesday")

//返回多参数
func getGasPrices() -> (Double,Double,Double){
    return(1,2,3)
}
getGasPrices()

//传递多参数
func sumOf(numbers:Int...) -> Int{
    var sum = 0
    for number in numbers{
        sum = sum + number
    }
    return sum
}

//函数嵌套函数
func addInlineFunction() -> Int {
    var y = 10
    func add(){
        y = y + 5
    }
    add()
    return y
}
addInlineFunction()

//函数作为另一个函数的返回值
func makeIncrementer() -> (Int -> Int){
    func addOne(number:Int)->Int{
        return 1 + number
    }
    return addOne
}

var increment = makeIncrementer()
increment(7)

//函数作为函数的参数
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(numbers, condition: lessThanTen)

//外部形参
func join(s1:String,s2:String,joiner:String) -> String{
    return s1 + joiner + s2
}
//当调用时候不够清晰
join("alex", s2: "wu", joiner: ",")

//通过添加外部形参来
func joinOut(string s1:String, toString s2:String, withString joiner:String) ->String {
    return s1 + joiner + s2
}
joinOut(string: "alex", toString: "wu", withString: ",")

//更简单的版本
func joinOutSimple(stringOne stringOne:String,toString:String,withJoiner:String) -> String{
    return stringOne + withJoiner + toString
}


//****************对象和类***************
class Shape {
    var numberofSides = 0
    func simpleDescription() -> String{
        return "A Shape with \(numberofSides) sides"
    }
}

var shape = Shape()
shape.numberofSides = 5
var shapeDescription = shape.simpleDescription()

class NamedShape {
    var numberofSides : Int = 0
    var name : String

    init(name:String){
        self.name = name
    }

    func simpleDescription() -> String{
        return "A Shape with \(numberofSides) sides"
    }
}

class Square:NamedShape {
    var sideLength:Double

    init(sideLength:Double,name:String){
        self.sideLength = sideLength
        super.init(name: name)
        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: "alex")
test.area()
test.simpleDescription()


//练习
class Circle:NamedShape{
    var radius : Double

    init(radius:Double,name:String){
        self.radius = radius
        super.init(name: name)
        numberofSides = 0
    }

    func area() -> Double{
        return radius * radius * M_PI
    }

    override func simpleDescription() -> String {
        return "A Circle with radius \(radius)"
    }
}

let circleObj = Circle(radius: 10, name: "alex")
circleObj.area()
circleObj.simpleDescription()


class EquilateralTriangle:NamedShape {
    var sideLength : Double = 0.0

    init(siLenth:Double,name:String){
        self.sideLength = siLenth
        super.init(name: name)
        numberofSides = 3
    }

    var perimeter : Double{
        get{
            return 3.0 * sideLength
        }

        set{
            sideLength = newValue / 3.0
        }
    }

    override func simpleDescription() -> String {
        return "An equilateral triagle with sides of length \(sideLength)."
    }
}

var triangle = EquilateralTriangle(siLenth: 3.5, name: "triangle")
triangle.perimeter
triangle.perimeter = 9
triangle.sideLength


//************************枚举*****************************

enum Rank:Int{
    case Ace = 1
    case Two,Three,Four,Five,Six,Sever,Eight,Nine,Ten
    case Jack, Queue, King
    func simpleDescription() -> String{
        switch self{
        case .Ace:
            return "ace"
        case .Jack:
            return "jack"
        case .Queue:
            return "queue"
        case .King:
            return "king"
        default:
            return String(self.rawValue)
        }
    }
}

let ace = Rank.Ace
let aceRawValue = ace.rawValue

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()

//**************************结构体*********************
struct Card {
    var rank:Rank
    var suit:Suit

    func sipleDescription() -> String{
        return "the \(rank.simpleDescription()) of \(suit.simpleDescription())"
    }
}

let threeOfSpades = Card(rank:.Three, suit:.Spades)
let des = threeOfSpades.sipleDescription()


//从服务器取日出日落时间
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 range")

switch success {
case let .Result(sunrise, sunset):
    let serverResponse = "Sunrise is at \(sunrise) and sunset is at \(sunset)."
case let .Error(error):
    let serverResponse = "Failure...  \(error)"
}


//*************************接口***********************
protocol ExampleProtocol{
    var simpleDescription:String{
        get
    }
    mutating func adjust()
}

//接口实现
class simpleClass : ExampleProtocol{
    var simpleDescription : String = "A simple structure"
    var anotherProperty : Int = 69105
    func adjust() {
        simpleDescription += "(adjusted)"
    }
}

var a = simpleClass()
a.adjust()
let aDes = a.simpleDescription

struct SimpleStructure : ExampleProtocol {
    var simpleDescription : String = "A simple structure"
    mutating func adjust() {
        simpleDescription += "(adjusted)"
    }
}

var b = SimpleStructure()
b.adjust()
let bDes = b.simpleDescription

//**************************添加扩展*************************
extension Int : ExampleProtocol{
    var simpleDescription : String{
        return "the number \(self)"
    }
    mutating func adjust() {
        self += 42
    }
}

7.simpleDescription

extension Double : ExampleProtocol{
    var simpleDescription : String{
        return "the number \(abs(self))"
    }
    mutating func adjust() {
        self += 0
    }
}

4.5.simpleDescription

//***************************泛型************************
//在尖括号里写一个名字来创建一个泛型函数或者类型。

After overview basic syntax, I plan practice it into demo. So,Here is a simple demo about show fonts in iOS. You can download it on github
https://github.com/surrenderios/iOSFontsWithSwift