Double question mark is a nil-coalescing operator . In plain terms, it is just a shorthand for saying != nil . First it checks if the the return value is nil, if it is indeed nil, then the left value is presented, and if it is nil then the right value is presented.
Read moreWhat are optionals in Swift?
An Optional is a type on its own, actually one of Swift 4’s new super-powered enums . It has two possible values, None and Some(T), where T is an associated value of the correct data type available in Swift 4.
Read moreWhat is overflow Swift?
Overflow Operators. If you try to insert a number into an integer constant or variable that can’t hold that value, by default Swift reports an error rather than allowing an invalid value to be created. This behavior gives extra safety when you work with numbers that are too large or too small.
Read moreWhat does += mean in Swift?
The expression a += 2 is shorthand for a = a + 2 . Effectively, the addition and the assignment are combined into one operator that performs both tasks at the same time . Note. The compound assignment operators don’t return a value. For example, you can’t write let b = a += 2 .
Read moreWhat is Swift framework?
Swift is a multipurpose, multi-paradigm compiled language created by Apple Inc . It is used for macOS, iPadOS, iOS, watchOS, Linux, and tvOS. The team that developed it makes use of an open-source LLVM compiler framework.
Read moreHow do you document in Swift?
Xcode provides an easy way to generate documentation. To use this feature, click on any class, property, function, or part you want to add a document. Then press ⌥ – Option + ⌘ – command + / or Editor > Structure > Add documentation from Xcode’s menu. Xcode will generate a document template for you.30 Kas 2019
Read moreWhat are the basics of Swift?
Swift provides its own versions of all fundamental C and Objective-C types, including Int for integers, Double and Float for floating-point values, Bool for Boolean values, and String for textual data .
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