Swift Closure _002_swift Closure Package

//: Playground-noun:a Place where people can playImport UIKit//-----closures-------////is a separate block of code that can be passed and used in code//closure in Swift is similar to block in OC//A function is a special kind of closure, a closed packet with a name.//1. Basic Use/*closure Syntax: {(parameter 1, parameter 2), return value type in closure code}*/func Add (A:int, B:int)-Int {returnA +b}let Closure= {(A:int, b:int), Intinch        returnA +B}add (1B:2) Closure (1,2)//the type of closure is the type of functionLet Closure2: (int, int)->int = {(A:int, b:int), intinch        returnA +B}//the simplification of the closure syntax, if you want to omit the type of parameters and return values in the closure, you need to explicitly specify the type of the closure variableLet closure3: (int, int)->int = {A, binch    returnA +B}//single-expression-style return: If there is only one expression in the code of the closure, return can be omittedLet Closure4: (int, int)->int = {A, binchA +B}closure4 (Ten,5)//parameter names can also be omittedLet Closure5: (int, int)->int = {$0+ $1}closure5 (1,2)//2. Using functions and closures to implement the traversal of elements in an array (execution of a piece of code for each element in a group)Func Emnumeratearray (array: [int], function: (int),Void) {         forIteminchArray {function (item)}}//the function that each element will executeFunc Printitem (varitem:int) {Item++print (item)}let array= [1,2,3,7]//Emnumeratearray (Array, Function:printitem)Let closure6= {(item:int)-Voidinchprint (item)}emnumeratearray (array, function:closure6) Emnumeratearray (array, function: {(item:int)-Voidinchprint (item)})//3. Trailing closures: If the closure is the last parameter, you can write the closure expression after the function parameter () to increase the readability of the CodeEmnumeratearray (Array) {(item:int), Voidinchprint (item)}//4. Closure Capture ValueFunc makeincrement (Forincrementor amount:int), (Void)Int {varTotal =0        //nested functions can capture variables or constants of external functions//func incrementor (), Int {//        //Total + = Amount//print ("total = \ (total)")//        //return Total//    }//    //return Incrementor//closures can capture externally defined variables or constantsLet Incrementor1: (void)->int = {(void)->intinch Total+=Amount Print ("Total = \ (total)")        returnTotal }returnIncrementor1}let closure7= Makeincrement (forincrementor:2) Closure7 () closure7 ()//closures are reference typesLet Closure8 = Makeincrement (forincrementor:3) Closure8 () Closure8 ( ) Let Closure9=closure8closure9 ()varA =0 //Intvarb =AA= A +1print (b)

Swift Closure _002_swift Closure Package