# append(contentsOf:) Adds the elements of a sequence or collection to the end of this collection. ``` mutating func append(contentsOf newElements: S) where S : Sequence, Self.Element == S.Element ``` ## Parameters `newElements` The elements to append to the collection. ## Discussion The collection being appended to allocates any additional necessary storage to hold the new elements. The following example appends the elements of a `Range` instance to an array of integers: ``` var numbers = [1, 2, 3, 4, 5] numbers.append(contentsOf: 10...15) print(numbers) // Prints "[1, 2, 3, 4, 5, 10, 11, 12, 13, 14, 15]" ``` > Complexity: O(*m*), where *m* is the length of `newElements`. --- 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)