What 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 more

Why do we use _ in Swift?

The _ is a placeholder for the parameter name . In your example, you call them differently, in the second function, you need to write the parameter name a: 1 . Swift’s function name convention is funcName(param1:param2:) , and it needs the _ as a placeholder to create the name of the function.

Read more

What is the symbol in Swift?

Put simply, @UIApplicationMain is an indicator for Swift applications that indicates which object is your application’s main application delegate file. In Objective-C application templates, you would have a trivial main. m C file which sets the application delegate.

Read more