Swift Learning-constants-variables-use of data types (ii)

I. Arrays in Swift

//Arrays in Swift//Nsarray *arr = @["", "" "];//the difference between a and OC array is to remove the previous @Let Arr11 = ["Zhangsan","Lisi"]print (ARR11)//iterate through each of the elements forAinchArr11 {print (a)}//print like OCPrint (Arr11 asNsarray)//strings are saved in the arrayLet arr = ["Zhangsan","Lisi"]//The NSObject is saved in the arrayLet arr1 = ["Zhangsan",1]//definition can only hold array of string typesvar array: [String]//initializing an arrayArray = ["Zhangsan"]//adding elementsArray.append ("Lisi") print (array)//Delete ElementArray.removeatindex (1) print (array)//Delete all elementsArray.removeall (keepcapacity:true) print (array.capacity)//Notice the change of the array capacity forIinch 0.. <Ten{array.append ("\ (i)") Print ("\ (array)---\ (array.capacity)")}//instantiate a new arrayvar array2 =[String] () array2.append ("1") Array2.append ("2")//Stitching ArraysArray + =array2print (Array)

Two. Dictionaries in Swift

//Create a dictionary//@{@ "key": "Value"};//Create a dictionary and create an array in swift, using the []//[String:nsobject] Type is the most common format used for iOS development in the futureLet dict = ["name":"Zhang San"," Age": -]//Get Valuedict["name"]//Traverse Dictionary forKeyinchdict.keys{Print (Dict[key])}//traversing a dictionary with a tuple type automatically assigns the key in the dictionary high School to the first variable in the tuple, assigning value to the second variable in the tuple//Note: The first one is key, the second value for(KK, VV)inchdict{print (KK) print (vv)}var dict2=[String:anyobject] ()//New Key/vale//if the corresponding key is not in the dictionary, it will be addedDict2 = ["name":"John Doe"," Age": -]dict2["Sex"]="Mans"Dict2//set the same key, the previous value will be overwrittendict2["name"] ="Money Six"Dict2//DeleteDict2.removevalueforkey ("name") Dict2//Merging Dictionariesvar dict3 = ["score": -] for(Key,value)inchdict3{Dict2[key]=Value}dict2var Dict4= ["Address":"Xiamen"] for(Key,value)inchdict4{Dict2.updatevalue (value, Forkey:key)}dict2

Three. Strings in Swift

//a string in Swift//define strings in OC with @ "Swift" "//Note: The string in OC is the string in NSString Swift//the string in OC is an object that inherits from the NSObject//the string in Swift is a struct//The performance of strings in Swift is higher than in OCvar str:string ="Zhang San"//Stitchingvar str2 ="Cool"Str+=str2//FormattingLet NUM8 = -Let name="Wangwu"//target: Name = Wangwu, age =//you can use \ () to stitch other values in Swiftvar STR3 ="name = \ (name), age = \ (NUM8)"//09:08:07//Note: All values must be placed in the array, even if only one value needs to be placed in the arrayvar STR4 = String (format:"%02d:%02d:%02d", arguments: [9,8,7])//Intercept//Note: In SWI, if you need to intercept a string, it is recommended to use the string in OC, because the string interception method of string in Swift is very complex to use .//strings in Swift can be easily converted with strings in OCvar str5:nsstring ="Zhang Sanha haha"var str6="Zhang San reply sent"  asNsstringvar subStr= Str5.substringwithrange (Nsmakerange (1,3))//strings in Swift are supported for direct traversalvar STR7 ="www:baidu.com" forCinchstr7.characters{Print (c)}

Four. Functions in Swift

//functions in Swift/*Swift defines the format of the function: semantics: Returns the value of the structure returned by the previous computed value, func function name (parameter list), return value {execute code}*///parameters with no return value//If the function does not return a value, write void//If the function does not return a value, it can be shortened//1. () Replace void//2. Can omit ()->voidFunc Say ()void{Print ("Hello World")}say () func say2 ()-() {print ("Hello World")}say2 () func say3 () {print ("Hello")}//There are no parameters for return valuesFunc GetNumber ()int{return 999}print (GetNumber ())//There are no return values for parameters//-(void) sum: (int) a B: (int) b//Swift2.0, the parameter name starting with the second parameter in the formal parameter is automatically made into a sticky note for improved readability//not until Swift2.0.func sum (a:int, b:int) {print (a+b)} SUM (TenB: -)//Add tags, add external parameters//x/y is called an external parameter, A/b is called internalfunc sum2 (x a:int,y b:int) {print (a+b)} SUM2 (x:TenY: -)//There are parameters with return valuesFunc sum4 (A:int, B:int)int{returnA +B}print (SUM4 (TenB: -))

Swift Learning-constants-variables-use of data types (ii)