Swift5.1官方教程完整版

Swift5.1官方教程\h2020-02-Swift教程（Swiftprintprint("Hello,//打印Hello, \h

varvarmyVariable=myVariable=letmyContant= letletimplicitInteger=letimlicitDouble=letexplicitDouble:Double=创建⼀个显式类型为创建⼀个显式类型为Float且值为的常数4 leta:Double=letlabelletlabel="ThewidthisletwidthLabel=label+尝试StringBinaryoperator'+'cannotbeappliedtooperandsoftype'String'and Binaryoperator'+'cannotbeappliedtooperandsoftype'String'and

letletapples=letappleSummary="Ihave\(apples)letfruitSummary="Ihave\(apples+oranges)piecesof⽤于

IIsaid"Ihave3AndthenIsaid"Ihave8piecesofletquotation=Isaid"Ihave\(apples)AndthenIsaid"Ihave\(apples+oranges)piecesof

varshoppingList=["catfish","water",shoppingList[1]="bottleofvaroccupations=["Malcolm":"Captain","Kaylee":"Mechanic",occupations["Jayne"]="PublicletletemptyArray=letemptyDictionary=[String:

shoppingListshoppingList=occupations=if和switch⽤于条件语句 for-repeat-while是可选的。其中的程序要 for-repeat-whileletletindividualScores=[75,43,103,87,varteamScore=forscoreinindividualScoresifscore>50teamScore+=}elseteamScore+= //Prints

ifscoreifscore{...

varvaroptionalString:String?=print(optionalString==//PrintsvaroptionalName:String?="Johnifletname=optionalNamegreeting="Hello,更改optionalName为nil。你会得到什么问候？添加⼀个elseoptionalName是nil

letletnickName:String?=letfullName:String="JohnletinformalGreeting="Hi\(nickName??letletvegetable="redswitchvegetablecaseprint("Addsomeraisinsandmakeantsonacase"cucumber",print("Thatwouldmakeagoodteacaseletxwhereprint("Isitaspicyprint("Everythingtastesgoodin//Prints"IsitaspicyredSwitchmustbe 因此不需要在每个case的代码末尾显式使⽤break退出switch。forfor-letletinterestingNumbers="Prime":[2,3,5,7,11,"Fibonacci":[1,1,2,3,5,"Square":[1,4,9,16,varlargest=for(kind,numbers)ininterestingNumbersfornumberinnumbersifnumber>largestlargest=//PrintsletinterestingNumbers=["Prime":[2,3,5,7,11,"Fibonacci":[1,1,2,3,5,"Square":[1,4,9,16,varlargest=for(kind,numbers)ininterestingNumbers{varlargestOfKind=0fornumberinnumbers{ifnumber>largest{largest=numberifnumber>largestOfKind{largestOfKind=numberprint("Thelargestnumberin\(kind)isprint("ThelargestnumberisThelargestnumberinSquareisThelargestnumberinFibonacciisThelargestnumberinPrimeisThelargestnumberis

varvarm=repeat m*=}whilem<//Prints foriin0..<4total+=//Prints

--funcfuncgreet(person:String,day:String)->Stringreturn"Hello\(person),todayisgreet(person:"Bob",day:删除 funcgreet(_person:String,onday:String)->String{return"Hello\(person),todayis\(day)."varmax=varsum=forscoreinscores{max=score}elseifscore<min{min=scoresum+=return(min,max,letstatistics=calculateStatistics(scores:[5,3,100,3,9])//Prints"120"//PrintsfuncreturnFifteen()->Int{vary=10y+=5funcmakeIncrementer()->((Int)->Int){funcaddOne(number:Int)->Int{return1+numberreturnvarincrement=print("theresultincrement(7)is//Print"theresultincrement(7)isforiteminlistifcondition(item){returntruereturnfunclessThanTen(number:Int)->Bool{returnnumber<10hasAnyMatches(list:numbers,condition:

numbers.mapnumbers.map({(number:Int)->Intletresult=3*return numbers.map({(number:Int)->Intletresult=number%2==0?result:return letmappedNumbers=numbers.map({numberin3*number//Prints"[60,57,21,letletsortedNumbers=numbers.sorted{$0>$1//Prints"[20,19,12, classclassShapevarnumberOfSides=funcsimpleDescription()->Stringreturn"Ashapewith\(numberOfSides)⽤shape.numberOfSides=varshapeDescription=这个⽤initclassNamedShapevarnumberOfSides:Int=0varname:S=funcsimpleDescription()->Stringreturn"Ashapewith\(numberOfSides) 如

classSquare:NamedShapevarsideLength:init(sideLength:Double,name:String){numberOfSides=4returnsideLength*overridefuncsimpleDescription()->Stringreturn"Asquarewithsidesoflengthlettest=Square(sideLength:5.2,name:"mytestsquare")制作另⼀个NamedShape的⼦类Circle。它以半径和名称作为其初始值设定项的参数。在类中实现area()和simpleDescription()⽅法。classEquilateralTriangle:NamedShapevarsideLength:Double=init(sideLength:Double,name:String){self.sideLength=sideLengthsuper.init(name:name)numberOfSides=3varperimeter:Double{get{return3.0*setoverridefuncsimpleDescription()->Stringreturn"Anequilateraltrianglewithsidesoflengthvartriangle=EquilateralTriangle(sideLength:3.1,name:"atriangle")//Prints//Prints

classTriangleAndSquarevartriangle:EquilateralTriangle{willSet{square.sideLength=varsquare:Square{willSet{triangle.sideLength=init(size:Double,name:String)square=Square(sideLength:size,name:triangle=EquilateralTriangle(sideLength:size,name:vartriangleAndSquare=TriangleAndSquare(size:10,name:"anothertestshape")//Prints"10.0"//PrintstriangleAndSquare.square=Square(sideLength:50,name:"largersquare")//Prints

letletoptionalSquare:Square?=Square(sideLength:2.5,name:"optionalletsideLength= caseace=1casetwo,three,four,five,six,seven,eight,nine,casejack,queen,funcsimpleDescription()->String{switchself{casereturn"ace"case.jack:case.queen:return"queen"case.king:return"king"returnletace=编写⼀个通过⽐较两个原始值来⽐较两个值的Rank

使⽤没有匹配的Rank时返回nil。ififletconvertedRank=Rank(rawValue:3)letthreeDescription=enumSuitcasespades,hearts,diamonds,funcsimpleDescription()->String{switchself{case.spades:return"spades"case.hearts:return"diamonds"case.clubs:returnletheartsDescription=给添加⼀个

分配值时，使⽤Suit.hearts 表示，因为self已经明 enumServerResponse括号⾥⾯必须指定关联值类型，不能没有caseletsuccessServerResponse.result("6:00am""8:09pm")letfailure=ServerResponse.failure("Outofcaseswitchsuccesscaselet.result(sunrise,print("Sunriseisat\(sunrise)andsunsetisat\(sunset).")caselet.failure(message):print("Failure...//Prints"Sunriseisat6:00amandsunsetisat8:09在ServerResponse的switch

structCard{varsuit:funcsimpleDescription()->Stringreturn"The\(rank.simpleDescription())ofletthreeOfSpades=Card(rank:.three,suit:letthreeOfSpadesDescription= varsimpleDescription:String{getmutatingfuncclassclassSimpleClass:ExampleProtocolvarsimpleDescription:String="AverysimplevaranotherProperty:Int=funcadjust()simpleDescription+="Now100%vara=SimpleClass()letaDescription=structSimpleStructure:ExampleProtocolvarsimpleDescription:String="Asimplestructure"mutatingfuncadjust(){simpleDescription+="varb=SimpleStructure()letbDescription=向ExampleProtocol中添加新的需求（注：如新的成员变量或者⽅法）。如何修改SimpleClass和SimpleStructure使其仍然符合协议？请注意，在SimpleStructure⽽SimpleClass

extensionInt:ExampleProtocol{varsimpleDescription:String{return"Thenumber\(self)"mutatingfuncadjust(){self+=42//Prints"Thenumber为Double类型添加absoluteValue（绝对值）letletprotocolValue:ExampleProtocol=//Prints"Averysimpleclass.Now100%//print(protocolValue.anotherProperty)//Uncommenttoseethe即使变量protocolValue在运⾏时类型 enumenumPrinterError:Errorcasecasecase

funcfuncsend(job:Int,toPrinterprinterName:String)throws->StringifprinterName=="NeverHasToner"throw 。其中，可以通过在前⾯写⼊try来标记可do- do-doletprinterResponse=trysend(job:1040,toPrinter:"BiSheng")}catch{将打印机名称更改为"NeverHasToner"，让函数send(job:toPrinter:) doletprinterResponse=trysend(job:1440,toPrinter:"Gutenberg")}catchPrinterError.onFireprint("I'lljustputthisoverhere,withtherestofthe}catchletprinterErrorasPrinterError{print("Printererror: