# replaceNil(with:) Replaces nil elements in the stream with the provided element. ``` func replaceNil(with output: T) -> Publishers.Map where Self.Output == T? ``` ## Parameters `output` The element to use when replacing `nil`. ## Return Value A publisher that replaces `nil` elements from the upstream publisher with the provided element. ## Discussion The [`replaceNil(with:)`](/documentation/Combine/Publisher/replaceNil(with:)) operator enables replacement of `nil` values in a stream with a substitute value. In the example below, a collection publisher contains a nil value. The [`replaceNil(with:)`](/documentation/Combine/Publisher/replaceNil(with:)) operator replaces this with `0.0`. ``` let numbers: [Double?] = [1.0, 2.0, nil, 3.0] numbers.publisher .replaceNil(with: 0.0) .sink { print("\($0)", terminator: " ") } // Prints: "Optional(1.0) Optional(2.0) Optional(0.0) Optional(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)