# prepend(_:) Prefixes a publisher’s output with the specified sequence. ``` func prepend(_ elements: S) -> Publishers.Concatenate, Self> where S : Sequence, Self.Output == S.Element ``` ## Parameters `elements` A sequence of elements to publish before this publisher’s elements. ## Return Value A publisher that prefixes the sequence of elements prior to this publisher’s elements. ## Discussion Use [`prepend(_:)`](/documentation/Combine/Publisher/prepend(_:)-v9sb) to publish values from two publishers when you need to prepend one publisher’s elements to another. In this example the [`prepend(_:)`](/documentation/Combine/Publisher/prepend(_:)-v9sb) operator publishes the provided sequence before republishing all elements from `dataElements`: ``` let prefixValues = [0, 1, 255] let dataElements = (0...10) cancellable = dataElements.publisher .prepend(prefixValues) .sink { print("\($0)", terminator: " ") } // Prints: "0 1 255 0 1 2 3 4 5 6 7 8 9 10" ``` --- 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)