# prefix(_:) Returns a sequence, up to the specified maximum length, containing the initial elements of the sequence. ``` func prefix(_ maxLength: Int) -> PrefixSequence ``` ## Parameters `maxLength` The maximum number of elements to return. The value of `maxLength` must be greater than or equal to zero. ## Return Value A sequence starting at the beginning of this sequence with at most `maxLength` elements. ## Discussion If the maximum length exceeds the number of elements in the sequence, the result contains all the elements in the sequence. ``` let numbers = [1, 2, 3, 4, 5] print(numbers.prefix(2)) // Prints "[1, 2]" print(numbers.prefix(10)) // Prints "[1, 2, 3, 4, 5]" ``` > Complexity: O(1) --- 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)