# lexicographicallyPrecedes(_:) Returns a Boolean value indicating whether the sequence precedes another sequence in a lexicographical (dictionary) ordering, using the less-than operator (`<`) to compare elements. ``` func lexicographicallyPrecedes(_ other: OtherSequence) -> Bool where OtherSequence : Sequence, Self.Element == OtherSequence.Element ``` ## Parameters `other` A sequence to compare to this sequence. ## Return Value `true` if this sequence precedes `other` in a dictionary ordering; otherwise, `false`. ## Discussion This example uses the `lexicographicallyPrecedes` method to test which array of integers comes first in a lexicographical ordering. ``` let a = [1, 2, 2, 2] let b = [1, 2, 3, 4] print(a.lexicographicallyPrecedes(b)) // Prints "true" print(b.lexicographicallyPrecedes(b)) // Prints "false" ``` > Note: This method implements the mathematical notion of lexicographical > ordering, which has no connection to Unicode. If you are sorting > strings to present to the end user, use `String` APIs that > perform localized comparison. > Complexity: O(*m*), where *m* is the lesser of the length of the > sequence and the length of `other`. --- 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)