The compiler will execute theletblock if it is null; otherwise, it will perform therunblock. Example 1: funmain(args: Array<String>) {valy="Hello"valx = y?.let {// This code runs if y is not nullprintln("Code A"
if let bestPlayer = players.highestScoringPlayer() { recordHolder = """ The record holder is \(bestPlayer.name),\ with a high score of \(bestPlayer.highScore)! """ } else { recordHolder = "No games have been played yet." } print(recordHolder) // The record holder is Erin, with...
if optionalString != nil { let unwrappedString = optionalString!} 相较于强制解包的不安全性，一般而言推荐另一种解包方式，即可选绑定。例如：if let optionalString = optionalString { // 这里optionalString不为nil，是已经解包后的类型，可以直接使用} 综上，在对可选类型进行解包时应尽量避免使用...
If condition is evaluated to true, the code inside the body of if is executed. If condition is evaluated to false, the code inside the body of if is skipped. Note: The code inside { } is the body of the if statement. Working of if statement Example 1: if Statement let number = ...
Finally, here’s an example of a for-in loop: // for-in loop for case let score in scores where score > 4 { ... } Replacing A Switch With If Case Let A switch statement is fine when I have something to do for all (or most) of the cases. Here’s an example where I only...
This function doesn’t compile as written above. The problem lies with the equality check, “if value == valueToFind”. Not every type in Swift can be compared with the equal to operator (==). If you create your own class or structure to represent a complex data model, for example, ...
This is true even if the new value is the same as the current value. This example’s willSet observer uses a custom parameter name of newTotalSteps for the upcoming new value. In this example, it simply prints out the value that’s about to be set. The didSet observer is called ...
Soifyou'reready, let'sgetstarted.所以,如果你准备好了,让我们开始吧。Allright, sowe'regoingtopracticewithanexercisecalledimitation.好吧,所以我们要练习一个叫作模仿的练习。Nowtheideaofimitationistotrytoimprovethedifferentdetailsofyourspeakingbymimickingexactlyhowsomeoneelse, usuallyanativespeaker, speaksthe...
#ifos(Linux)// Code specific to Linux#elseif os(macOS)// Code specific to macOS#endif#ifcanImport(UIKit)// Code specific to platforms where UIKit is available#endif 此外,你可能需要定义最低部署目标。注意以下软件包清单如何通过将最低部署目标作为值传递给Package(英文)构造器的platforms参数。但是,...
The first of which is life can be heavy, especially if you try to carry it all at once, part of growing up and moving into new chapters of your life, is about catch and release. What i mean by that is knowing what things to keep and what things to release. You can’t carry all...