swift参考了OC，Rust,Haskell,Ruby,Python,C#等语言的特性。首先，学习这门语言是速学的，我不想浪费太多时间在笔记这门语言和其他语言的哪里不同，特性你自己亲自实践就知道了。下面是我亲自实践总结的一点点皮毛而已。
废话不多说，直接上代码：
1 声明变量和常量
var str: String = "Look what I can do"
var age: Int = 18
let favoriteNumber: Int = 42
代替上面的简单写法就是：
var str = "Look what I can do"
var age = 18
let favoriteNumber = 42
2 字符串声明和初始化或者说是直接赋值
var favoriteGame: String = "Mario Kart"
favoriteGame = "Super Smash Bros"
3 操作符的使用与if语法
let batmanCoolness = 10
var supermanCoolness = 9
let aduamanCoolness = 1
batmanCoolness < supermanCoolness
batmanCoolness > supermanCoolness
supermanCoolness >= 8
batmanCoolness == (supermanCoolness + aduamanCoolness)
batmanCoolness > aduamanCoolness && batmanCoolness == (aduamanCoolness + supermanCoolness)
batmanCoolness < supermanCoolness || aduamanCoolness < supermanCoolness
var spidermanCoolness = 7
(spidermanCoolness + aduamanCoolness) > supermanCoolness
spidermanCoolness == 7 && aduamanCoolness == 2
if(batmanCoolness > spidermanCoolness){
spidermanCoolness = spidermanCoolness - 1
}else if(batmanCoolness >= spidermanCoolness){
spidermanCoolness = spidermanCoolness - 1
}else{
spidermanCoolness = spidermanCoolness + 1
}
if(supermanCoolness < spidermanCoolness) {
supermanCoolness = supermanCoolness - 1
spidermanCoolness = spidermanCoolness + 1
} else if (supermanCoolness == spidermanCoolness) {
supermanCoolness = supermanCoolness + 1
spidermanCoolness = spidermanCoolness + 1
} else {
supermanCoolness = supermanCoolness + 1
spidermanCoolness = spidermanCoolness - 1
}
4 print 语法的使用
print("Hello,World")
print("Ry is awesome")
print(batmanCoolness)
5 字符串插入的使用
var apples = 5
print("Sally has \(apples)apples")
print("Sally has \(apples - 5) apples")
6 可选optional使用（注意：0或者一个具体值）
var optionalNumber: Int? = 5
optionalNumber = nil
if let number = optionalNumber {
print("It is a number")
}
else{
print("It is not a number")
}
7 类型转换
var languagesLearned: String = "3"
var languagesLearnedNum: Int? = Int(languagesLearned)
如：
var tutorialTeam: String = "55"
var editorialTeam = 23
var tutorialTeamNum: Int? = Int(tutorialTeam)
if let numTutorial = tutorialTeamNum {
if(numTutorial > editorialTeam) {
print("\(numTutorial) is greater than \(editorialTeam)")
} else if (numTutorial < editorialTeam) {
print("\(numTutorial) is less than \(editorialTeam)")
} else {
print("\(numTutorial) is equal to \(editorialTeam)")
}
} else {
print("Invalid entry")
}
8 方法的使用
例子：func randomIntBetween(low:Int, high:Int) -> Int {
let range = high - (low - 1)
return (Int(arc4random()) % range) + (low - 1)
}
新建项目PeopleDatabase
main.swift
import Foundation
//var newPerson = Person() //创建对象newPerson类的person,等于一个Person对象初始化。即可调用person类
//
//newPerson.enterInfo()
//newPerson.printInfo()
// 加入循环
var response: String
var people: [Person] = [] //创建数组
repeat{
var newPerson = Person()
newPerson.enterInfo()
newPerson.printInfo()
people.append(newPerson)
newPerson.printInfo()
print("Do you want to enter another name?(y/n)")
response = input()
}while(response == "y")
print("Number of people in the database: \(people.count)")
for onePerson in people {
onePerson.printInfo()
}
新建一个Person类
Person.swift
import Foundation
class Person {//创建了一个person的类，类不仅有属性，还可以包含方法
var firstName = ""
var lastName = ""
var age = 0
func input() -> String {
let keyboard = NSFileHandle.fileHandleWithStandardInput()
let inputData = keyboard.availableData
let rawString = NSString(data: inputData, encoding:NSUTF8StringEncoding)
if let string = rawString {
return string.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
} else {
return "Invalid input"
}
}
func changeFirstName(newFirstName:String) { //1创建方法
firstName = newFirstName
}
func enterInfo() {//2创建方法
print("What is the first name?")
firstName = input()
print("What is \(firstName)'s last name?")
lastName = input()
print("How old is \(firstName) \(lastName)")
let userInput = Int(input())
if let number = userInput {
age = number
}
}
func printInfo() {//3创建方法
// print("First Name: \(firstName)")
print("\(firstName) \(lastName) is \(age) years old")
}
}
记得导入文件helpers.swift的辅助文件
helpers.swif
import Foundation
func input() -> String {
let keyboard = NSFileHandle.fileHandleWithStandardInput()
let inputData = keyboard.availableData
let rawString = NSString(data: inputData, encoding:NSUTF8StringEncoding)
if let string = rawString {
return string.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
} else {
return "Invalid input"
}
}
func randomIntBetween(low:Int, high:Int) -> Int {
let range = high - (low - 1)
return (Int(arc4random()) % range) + (low - 1)
}
9 swift的导入类的时候，不需要导入类的头文件，直接创建类直接就可以调用了，这是和OC特殊的不同点，主要是方便。节省很多开发时间和提高开发效率
10
//常量的声明
let swiftTeam = 13
let iOSTeam = 54
let otherTeams = 48
//变量 的声明和值的改变
var totalTeam = swiftTeam + iOSTeam + otherTeams
totalTeam += 1
let priceInferred = 19.99
let priceExplict: Double = 19.99
let onSaleInferred = true
let onSaleExplicit: Bool = false
let nameInferred = "Whoopie Cushion"
let nameExplicit: String = "Whoopie Cushion"
if onSaleInferred {
print("\(nameInferred) on sale for \(priceInferred)!")
}else{
print("\(nameInferred) at regular price: \(priceInferred)!")
}
//类的定义和调用
class TipCalculator{
let total: Double
let taxPct: Double
let subtotal: Double
init(total:Double,taxPct: Double){ //初始化方法
self.total = total
self.taxPct = taxPct
subtotal = total/(taxPct + 1)
}
func cailcTipWithTipPct(tipPct: Double) -> Double {
return subtotal * tipPct
}
func printPossibleTips(){
print("15%:\(cailcTipWithTipPct(0.15))")
print("18%:\(cailcTipWithTipPct(0.18))")
print("20%:\(cailcTipWithTipPct(0.20))")
}
func returnPossibleTips() -> [Int: Double] {
let possibleTipsInferred = [0.15,0.18,0.20]
var retval = [Int: Double]()
for possibleTip in possibleTipsInferred {
let intPct = Int(possibleTip * 100)
retval[intPct] = cailcTipWithTipPct(possibleTip)
}
return retval
}
}
let tipCalc = TipCalculator(total: 33.25,taxPct: 0.06)
tipCalc.printPossibleTips()
11 //Unnamed Tuples元组的使用---无命名
//let tipAndTotal = (4.00,25.19）或者
let tipAndTotal:(Double,Double) = (4.00,25.19)
//元组点语法的访问index（第几个元素）
tipAndTotal.0
tipAndTotal.1
//另外设置一个元组赋值第一个元组，然后访问里面的元素
let(theTipAmt,theTotal) = tipAndTotal
theTipAmt
theTotal
//#####元组的使用 有命名
//let tipAndTotalNamed:(tipAmt:Double, total:Double) = (4.00, 25.19)也可以这样
let tipAndTotalNamed = (tipAmt:4.00,total:25.19)
tipAndTotalNamed.tipAmt
tipAndTotalNamed.total
//#####元组的使用 Returning Tuples
let total = 21.19
let taxPct = 0.06
let subtotal = total/(taxPct + 1)
func calcTipWithTipPct(tipPct:Double) -> (tipAmt:Double,total:Double) {
let tipAmt = subtotal * tipPct
let finalTotal = total + tipAmt
return(tipAmt,finalTotal)
}
calcTipWithTipPct(0.20)
12 //A Full Prototype 完整的原型
class TipCalculatorModel {
var total: Double
var taxPct: Double
var subtotal: Double {
get {
return total / (taxPct + 1)
}
}
init(total: Double, taxPct: Double) {
self.total = total
self.taxPct = taxPct
}
func calcTipWithTipPct(tipPct:Double) -> (tipAmt:Double, total:Double) {
let tipAmt = subtotal * tipPct
let finalTotal = total + tipAmt
return (tipAmt, finalTotal)
}
func returnPossibleTips() -> [Int: (tipAmt:Double, total:Double)] {
let possibleTipsInferred = [0.15, 0.18, 0.20]
var retval = [Int: (tipAmt:Double, total:Double)]()
for possibleTip in possibleTipsInferred {
let intPct = Int(possibleTip*100)
retval[intPct] = calcTipWithTipPct(possibleTip)
}
return retval
}
}
13 //Protocols
protocol Speaker{
func Speak()
}
class Vicki: Speaker {
func Speak() {
print("Hello, I am Vicki!")
}
}
class Ray: Speaker {
func Speak() {
print("Yo, I am Ray!")
}
}
class Animal {
}
class Dog : Animal, Speaker {
func Speak() {
print("Woof!")
}
}
14//Optional Protocols
@objc protocol Speak{
func Speak()
optional func TellJoke()
}
//If you get an error, make sure to add this line to the top of your playground:import Foundation
//protocol的使用调用
var speaker:Speaker
speaker = Ray()
speaker.Speak()
speaker = Vicki()
speaker.Speak()
15//Delegates
protocol DateSimulatorDelegate {
func dateSimulatorDidStart(sim:DateSimulator, a:Speaker, b:Speaker)
func dateSimulatorDidEnd(sim:DateSimulator, a: Speaker, b:Speaker)
}
class DateSimulator {
let a:Speaker
let b:Speaker
var delegate:DateSimulatorDelegate?
init(a:Speaker, b:Speaker) {
self.a = a
self.b = b
}
func simulate() {
delegate?.dateSimulatorDidStart(self, a:a, b: b)
print("Off to dinner...")
a.Speak()
b.Speak()
print("Walking back home...")
// a.TellJoke?()
// b.TellJoke?()
delegate?.dateSimulatorDidEnd(self, a:a, b:b)
}
}