# contains(where:) Publishes a Boolean value upon receiving an element that satisfies the predicate closure. ``` func contains(where predicate: @escaping (Self.Output) -> Bool) -> Publishers.ContainsWhere ``` ## Parameters `predicate` A closure that takes an element as its parameter and returns a Boolean value that indicates whether the element satisfies the closure’s comparison logic. ## Return Value A publisher that emits the Boolean value `true` when the upstream publisher emits a matching value. ## Discussion Use [`contains(where:)`](/documentation/Combine/Publisher/contains(where:)) to find the first element in an upstream that satisfies the closure you provide. This operator consumes elements produced from the upstream publisher until the upstream publisher produces a matching element. This operator is useful when the upstream publisher produces elements that don’t conform to `Equatable`. In the example below, the [`contains(where:)`](/documentation/Combine/Publisher/contains(where:)) operator tests elements against the supplied closure and emits `true` for the first elements that’s greater than `4`, and then finishes normally. ``` let numbers = [-1, 0, 10, 5] numbers.publisher .contains {$0 > 4} .sink { print("\($0)") } // Prints: "true" ``` --- 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)