# shuffle(using:) Shuffles the collection in place, using the given generator as a source for randomness. ``` mutating func shuffle(using generator: inout T) where T : RandomNumberGenerator ``` ## Parameters `generator` The random number generator to use when shuffling the collection. ## Discussion You use this method to randomize the elements of a collection when you are using a custom random number generator. For example, you can use the `shuffle(using:)` method to randomly reorder the elements of an array. ``` var names = ["Alejandro", "Camila", "Diego", "Luciana", "Luis", "Sofía"] names.shuffle(using: &myGenerator) // names == ["Sofía", "Alejandro", "Camila", "Luis", "Diego", "Luciana"] ``` > Complexity: O(*n*), where *n* is the length of the collection. > Note: The algorithm used to shuffle a collection may change in a future > version of Swift. If you’re passing a generator that results in the > same shuffled order each time you run your program, that sequence may > change when your program is compiled using a different version of > Swift. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)