Arrays vs sets vs tuples

Arrays, sets, and tuples can seem similar at first, but they have distinct uses. To help you know which to use, here are some rules.

If you need a specific, fixed collection of related values where each item has a precise position or name, you should use a tuple:

let address = (house: 555, street: "Taylor Swift Avenue", city: "Nashville")

If you need a collection of values that must be unique or you need to be able to check whether a specific item is in there extremely quickly, you should use a set:

let set = Set(["aardvark", "astronaut", "azalea"])

If you need a collection of values that can contain duplicates, or the order of your items matters, you should use an array:

let pythons = ["Eric", "Graham", "John", "Michael", "Terry", "Terry"]

Arrays are by far the most common of the three types.

SAVE 50% To celebrate WWDC23, all our books and bundles are half price, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.

Save 50% on all our books and bundles!