---
title: "filter(_:)"
framework: combine
role: symbol
role_heading: Instance Method
path: "combine/just/filter(_:)"
---

# filter(_:)

## Declaration

```swift
func filter(_ isIncluded: (Output) -> Bool) -> Optional<Output>.Publisher
```

## See Also

### Filtering elements

- [compactMap(_:)](combine/just/compactmap(_:).md)
- [removeDuplicates()](combine/just/removeduplicates().md)
- [removeDuplicates(by:)](combine/just/removeduplicates(by:).md)
- [tryRemoveDuplicates(by:)](combine/just/tryremoveduplicates(by:).md)
- [replaceEmpty(with:)](combine/just/replaceempty(with:).md)
- [replaceError(with:)](combine/just/replaceerror(with:).md)