# replaceEmpty(with:) Replaces an empty stream with the provided element. ``` func replaceEmpty(with output: Self.Output) -> Publishers.ReplaceEmpty ``` ## Parameters `output` An element to emit when the upstream publisher finishes without emitting any elements. ## Return Value A publisher that replaces an empty stream with the provided output element. ## Discussion Use [`replaceEmpty(with:)`](/documentation/Combine/Publisher/replaceEmpty(with:)) to provide a replacement element if the upstream publisher finishes without producing any elements. In the example below, the empty `Double` array publisher doesn’t produce any elements, so [`replaceEmpty(with:)`](/documentation/Combine/Publisher/replaceEmpty(with:)) publishes `Double.nan` and finishes normally. ``` let numbers: [Double] = [] cancellable = numbers.publisher .replaceEmpty(with: Double.nan) .sink { print("\($0)", terminator: " ") } // Prints "(nan)". ``` Conversely, providing a non-empty publisher publishes all elements and the publisher then terminates normally: ``` let otherNumbers: [Double] = [1.0, 2.0, 3.0] cancellable2 = otherNumbers.publisher .replaceEmpty(with: Double.nan) .sink { print("\($0)", terminator: " ") } // Prints: 1.0 2.0 3.0 ``` --- 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)