头文件

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//: Playground - noun: a place where people can play
import UIKit
//setting value

初始化

变量

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var str = "Hello, playground"
var userAge:Int = 30
var userAgeInDays:Int = userAge * 365

常量

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let introduced: Int = 2014
let isAwesome: Bool = true
//===可以直接定义，自动适配变量类型===
//let languageName = "Swift"
//var version = 1.0
//let introduced = 2015
//let isAwesome = true
//let π = 3.1415927
//let 中文 = "Chinese"
//let 🐮 = "cow"

运算

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var dogInt:UInt32=0x1F436
var chInt:UInt32=0x1F425
var heartInt:UInt32=0x2665
var dollarInt:UInt32=0x0024
var pinkInt:UInt32=0x1F496
let dog = UnicodeScalar(dogInt)?.escaped(asASCII: false)
let chicken = UnicodeScalar(chInt)?.escaped(asASCII: false)
let dollar = UnicodeScalar(dollarInt)?.escaped(asASCII: false)
let heart = UnicodeScalar(heartInt)?.escaped(asASCII: false)
let pink = UnicodeScalar(pinkInt)?.escaped(asASCII: false)
let someString = "I apper to be a string" //inferred to be of type String
//urlRequest.HTTPMethor = "POST"
let components = "~/Documents/Swift".components(separatedBy: "/") //["~", "Documents", "Swift"]
for character in "🐶🐱🐭🐹".characters {
    print("\(character)")
}
let dog2 = "🐶"
let cow2 = "🐮"
var dogCow = dog2+cow2
//math operation
let a = 3, b = 5
let mathResult = "\(a) time \(b) is \(a*b)"
var varibleString = "Horse"
varibleString += " and carriage"
let constantString = "Highlander"

数组

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var name = ["Anna", "Alex", "Brian", "Jack"]
for now in name {
    print("Hello, \(now)")
}
//change the array
var shoppingList = ["Eggs", "Milk"]
print(shoppingList[0])
shoppingList.append("Flour")
shoppingList += ["Cheese", "Butter", "Chocolate Spread"]
shoppingList[0] = "Six Eggs"
print(shoppingList)
shoppingList[2...4] = ["Bananas", "Apples"]
print(shoppingList)

字典

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var numberOfLegs = ["ant": 6, "snake": 0, "cheetah": 4]
numberOfLegs["spider"] = 273
// for in map style
for (animalName, legCount) in numberOfLegs {
    print("\(animalName)s have \(legCount) legs")
}
//numberOfLegs["arrdvark"] = 101
print(numberOfLegs)
// if not found in map set
let possibleLegCount:Int? = numberOfLegs["arrdvark"]
if possibleLegCount == nil{
    print("Aardvark wasn't found")
}else{
    let intcont:Int = possibleLegCount!
    print("arrdvark is \(intcont)")
}
if let legcount = possibleLegCount{
    print("arrdvark has \(legcount) legs")
}

函数

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//无返回值的函数
func sayhello(name:String = "Beyond"){
    print("hello \(name)")
}
sayhello()
sayhello(name:"Bob")
//有返回值的函数
func buildgreeting(name:String = "Beyond")->String{
    return "Hi"+name
}
print(buildgreeting())
print(buildgreeting(name:"Leaon"))
func doublereturn() -> (code:Int,message:String){
    // do sth here
    return (200,"Success")
}
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func wholename (_num:Int) -> (firstname:String,lastname:String){
    let fn=["Loli","Tenk","Jon","Peeck","Beyond"]
    let ln=["Sccot","Alice","Jonny","Freank","Leon"]
    return (fn[_num],ln[_num])
}
let allname=wholename(_num: 2)
print("number 2 's name is \(allname.firstname) \(allname.1)")
let setFree={print("zhangbinbin最衰")}
setFree
//可变熟练的参数输入
func sumOf(numbers:Double...) -> (Double){
    var sum=0.0
    for number in numbers{
        sum += number
    }
    return sum/Double(numbers.count)
}
print("the sum is \(sumOf(numbers: 1,2,5,5,66))")

循环

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// for statement
for i in 0..<5 {
    print(i)
}
var ti = 1
while ti < 100 {
    print("ti is  \( ti)")
    ti = ti + ti;
}
ti = 1
repeat{
    print("ti is \(ti)" )
    ti = ti * 3
}while ti < 10

选择

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var sender:Int = 1
switch sender{
    case 1,2,3,4,5:
    print("sender is 1,2,3,4,5")
    case 99:
    print("sender is 99")
    default:
    print("W T F")
}
let life = ["cat":"animal","dog":"animal","flower":"plant","tree":"plant","tiger":"animal","cucomber":"plant"]
let wlife = life["tiger"]
switch wlife{
    case "animal"?:
        print("this life is animal")
    case "plant"?:
        print("this life is plant")
    default:
        print("this is alien")
}

闭包

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//Closures is a peices of programe
let greetingPrinter:()->()={
    print("this is a closures")
}
greetingPrinter
//Closures as parameter
func repeating(count:Int,task:()->()){
    for i in 0...count{
        task()
    }
}
repeating(count:3,task:greetingPrinter)