---
title: "removeDuplicates(by:)"
framework: swift
role: symbol
role_heading: Instance Method
path: "swift/optional/publisher-swift.struct/removeduplicates(by:)"
---

# removeDuplicates(by:)

## Declaration

```swift
func removeDuplicates(by predicate: (Optional<Wrapped>.Publisher.Output, Optional<Wrapped>.Publisher.Output) -> Bool) -> Optional<Wrapped>.Publisher
```