# tryFilter(_:) Republishes all elements that match a provided error-throwing closure. ``` func tryFilter(_ isIncluded: @escaping (Self.Output) throws -> Bool) -> Publishers.TryFilter ``` ## Parameters `isIncluded` A closure that takes one element and returns a Boolean value that indicated whether to republish the element or throws an error. ## Return Value A publisher that republishes all elements that satisfy the closure. ## Discussion Use [`tryFilter(_:)`](/documentation/Combine/Publisher/tryFilter(_:)) to filter elements evaluated in an error-throwing closure. If the `isIncluded` closure throws an error, the publisher fails with that error. In the example below, [`tryFilter(_:)`](/documentation/Combine/Publisher/tryFilter(_:)) checks to see if the element provided by the publisher is zero, and throws a `ZeroError` before terminating the publisher with the thrown error. Otherwise, it republishes the element only if it’s even: ``` struct ZeroError: Error {} let numbers: [Int] = [1, 2, 3, 4, 0, 5] cancellable = numbers.publisher .tryFilter{ if $0 == 0 { throw ZeroError() } else { return $0 % 2 == 0 } } .sink( receiveCompletion: { print ("\($0)") }, receiveValue: { print ("\($0)", terminator: " ") } ) // Prints: "2 4 failure(DivisionByZeroError())". ``` --- 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)