codecademy swift

First, mind mapSecond, the Code//This will make the code very ugly . ifX! = Nil Y! =Nil {print ("x or Y are not equal to null")} print ("x or Y has an empty") //1 use??Let name:string? ="I am the most handsome"Let age:int= - //?? Represents a selectable unpacking package//The following two execution results behave differently due to changes in values,Print (name??""+ String (age))//I'm the most handsome, because he has the lowest priorityPrint (name??"") + String (age))//I am the

following method requires the Somefunctionthattakesaclosure function pointer passed into the previous interface, Func initwithclosure (closure:sendvalueclosure?). {//Assign the function pointer to the Myclosure closure, which covers references to local variables in the somefunctionthattakesaclosure function myclosure = closure} init (Nibname nibn Ameornil:string, bundle Nibbundleornil:nsbundle?) {Super.init (Nibname:nibnameornil, Bundle:nibbundleornil)//Custom initialization} override func View

If you want to make a custom configuration, you can inherit the base class UIView.The map app needs to touch multiple touch more.Opaque non-transparentHidden hidden, such as the download of the progress bar, if downloaded, you can set this property to make the progress bar disappearClears graphics context If a view needs to update the content, you can check this property by clearing the previous contentClip Subview truncate the child view boundary if the child view of a view is a button, but thi

Swift keyword summary and swift keyword Summary There are four common keywords: Declaration-related keywords: class, deinit, enum, extension, func, import, init, let, protocol, static, struct, subscript, typealias, and var. Statement-related keywords: break, case, continue, default, do, else, fallthrough, if, in, for, return, switch, where, and while. Expression and type Keyword: as, dynamicType, is, ne

Build a binary tree (swift) and a binary tree swiftBuild a binary tree (swift) PublicclassALTree Var key: T? Var left: ALTree? Var right: ALTree? Func addNode (key: T ){ If (self. key = nil ){ Self. key = key Return } If (key If (self. left! = Nil ){ Left !. AddNode (key) } Else { Var leftChild: ALTree = ALTree () LeftChild. key = key Self. left = leftChild } } If (key> self. key ){ If (self. right! = N

[Swift learning] Swift programming tour-collection type Dictionaries (8), swiftdictionaries A dictionary is a storage that stores multiple types of data. Each value is associated with a unique key as the identifier of the value data in the dictionary. Unlike the data items in the array, the data items in the dictionary are not in specific order. Dictionary writing Dictionary Create an empty dictionary var

Application source code similar to "on demand" compiled by Swift, swift source code An App written in SwiftOverview This project was prepared to consolidate Swift's knowledge. The materials are from the official App Use Storyboard + Xib + Autolayout to implement the UI part Because the project is not complex, the directory structure is relatively simple. A module corresponds to a folder. There is

Swift UI special training 43 Swift APP boot page, swiftui When an APP is loaded for the first time, a boot page is usually used to show features or tell users how to use them. Open our Storyboard, import a Page View Controller, make the following settings, and modify the Transition Style: Set the storyboard ID to PageViewController for our Page View Controller. Now you should want to know how we can edit o

Swift social application text input optimization summary, swift social text SummaryI. Input-Related Optimization Problems In most applications, there is a need for input. In the face of a large number of users, their ideas vary, and the input text content is strange. In the face of different input, how should we optimize the input experience? Here we will summarize the Input-related questions, mainly as fol

Zhao yazhi _ Swift (4) _ asserted, Zhao yazhi _ swift asserted Optional. You can determine whether a value exists. You can optimize the processing of missing values in the code. However, in some cases, if the value is missing or does not meet specific conditions, your code may not need to be executed. In this case, you can trigger an assertion in your code to end code running and debug the code to find the

Random Number Generation (swift), random number generation swiftRandom Number Generation (swift) by Wu xueying OverridefuncviewDidLoad (){ Super. viewDidLoad () For _ in0... 100 { Println (randomInRange (1... 6 )) } } Func randomInRange (range: Range Let count = UInt32 (range. endIndex-range. startIndex) Return Int (arc4random_uniform (count) + range. startIndex} Copyright Disclaimer: This ar

Use md5 in swift and md5 in swiftUse md5by Wu xueying in swift Add # import Let cString = self. cStringUsingEncoding (NSUTF8StringEncoding) Let length = CUnsignedInt ( Self. lengthOfBytesUsingEncoding (NSUTF8StringEncoding) ) Let result = UnsafeMutablePointer CC_MD5 (cString !, Length, result) ReturnString (format: "% 02x % 02x % 02x % 02x % 02x % 02x % 02x % 02x % 02x % 02x % 02x % 02x % 02x % 02x % 02x %

Functions and closures functions and closures) Use of functions There is a significant difference between Function Definition and OC in swift. Use func to define the function, define the number and type of struct in brackets, and use-> to define the type of return value. func greet(name: String, day: String) -> String { return "Hello \(name), today is \(day)."}greet("Bob", "Tuesday") Use a single tuple () to return multiple return values func

fengsh998 Original address: http://blog.csdn.net/fengsh998/article/details/30354127 reprint please indicate the sourceSwift does not use a new set of threads, using a set of threads from the OC source. The following example illustrates the use of threads in Swift.Its use includes common: NSTHREAD,NSOPERATIONQUEUE,GCGImport UIKit class Swiftthreaddemo:uiviewcontroller {var queue = Nsoperationqueue ()//init ()//{ Alloc//Super.init ()//} deinit {//dealloc} func Test Gcdthread () {Dis

While watching Apple's official swift language, there was an experiment: the Write an extension for the Double type, which is the add an Absolutevalue property. When you add attributes directly using extension, there is an error (of course, the code is not finished, playground is good to use).Extension double {//Add Absolutevalue property to double type by using extension. var absolutevalue:double { }}result Error, said: ' var ' declaration wit

The two languages that are currently being developed for iOS are OC and Swift, both of which are currently showing a trend. But in order to develop well, learning two languages is very necessary. Now I'm going to start learning swift. This is my first Swift program--hello world. Apple introduced a very good tool for developing

Closures are functional self-contained modules that can be passed and used in code. Closures in swift are similar to blocks in C and objective-C, and Lambdas in other programming languages. Closure is acceptable. CaptureAnd store references to any constants and variables in the context. This is the so-called closure and enclose these constants and variables, commonly known as closures. Swift will manage Cap

Closures are self-contained function modules that can be passed and used in code, much like blocks in C and OC, and Lambdasbas expressions in. Net.Closures can capture and store references to any constants and variables in the context in which they are located. Packets wrapped around these constants and variables are commonly known as closures. Swift manages the memory operations involved in the capture process for you. The following is the 3 represen

Swift is a new language used to design iOS and Mac OS X applications. Swift features ? Swift retains the advantages of C and Objective-C and abandons the limitations it imposes to be compatible with the C language. ? Swift incorporates the security programming model and adds some modern features to make it easier

Swift-control statement and swift-Statement Today, I wrote some basic knowledge about the swift language I learned a few days ago. I want to write it a few days ago, but the tool for inserting Code does not have Swift, put it down (the "huge" blog Park doesn't support Swift