Swift’s variadic functions let us accept any number of parameters of the same type, separated by a comma. Inside the function they are handed to us as an array, which we can index into, loop over, and so on.
The power of variadic parameters is that we can treat them as if they weren’t variadic most of the time. For example, if you had an
open() function that opened a file for editing in Preview, TextEdit, or whatever was the correct program, you might call it like this:
But that same function could take a variadic parameter – lots of filenames to open, so several could be opened at once:
open("photo.jpg", "recipes.txt", "myCode.swift")
So, by making that parameter variadic, we can open up a whole range of additional functionality without having to change the way the function is called – it’s really useful!
As for when you should use them, chances are you won’t use them that much while you’re learning because you’re going to be focused on very specific problems that are usually fairly small. But as your skills increase, you’ll find that you can change your existing functions to make them variadic without breaking any of your code – you can add functionality without changing what you already have.
SPONSORED Are you tired of wasting time debugging your Swift app? Instabug’s SDK is here to help you minimize debugging time by providing you with complete device details, network logs, and reproduction steps with every bug report. All data is attached automatically, and it only takes a line of code to setup. Start your free trial now and get 3 months off exclusively for the Hacking with Swift Community.
Link copied to your pasteboard.