---
title: Publishers.Contains
framework: combine
role: symbol
role_heading: Structure
path: combine/publishers/contains
---

# Publishers.Contains

A publisher that emits a Boolean value when it receives a specific element from its upstream publisher.

## Declaration

```swift
struct Contains<Upstream> where Upstream : Publisher, Upstream.Output : Equatable
```

## Topics

### Creating a contains Publisher

- [init(upstream:output:)](combine/publishers/contains/init(upstream:output:).md)

### Declaring supporting types

- [Publishers.Contains.Output](combine/publishers/contains/output-swift.typealias.md)
- [Publishers.Contains.Failure](combine/publishers/contains/failure.md)

### Inspecting publisher properties

- [upstream](combine/publishers/contains/upstream.md)
- [output](combine/publishers/contains/output-swift.property.md)

### Comparing publishers

- [==(_:_:)](combine/publishers/contains/==(_:_:).md)

### Default Implementations

- [Equatable Implementations](combine/publishers/contains/equatable-implementations.md)

## Relationships

### Conforms To

- [Equatable](swift/equatable.md)
- [Publisher](combine/publisher.md)

## See Also

### Applying matching criteria to elements

- [Publishers.ContainsWhere](combine/publishers/containswhere.md)
- [Publishers.TryContainsWhere](combine/publishers/trycontainswhere.md)
- [Publishers.AllSatisfy](combine/publishers/allsatisfy.md)
- [Publishers.TryAllSatisfy](combine/publishers/tryallsatisfy.md)