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

# collect(_:)

Collects up to the specified number of elements, and then emits a single array of the collection.

## Declaration

```swift
func collect(_ count: Int) -> Publishers.CollectByCount<Self>
```

## Parameters

- `count`: The maximum number of received elements to buffer before publishing.

## Mentioned in

Processing Published Elements with Subscribers

## Return Value

Return Value A publisher that collects up to the specified number of elements, and then publishes them as an array.

## Discussion

Discussion Use collect(_:) to emit arrays of at most count elements from an upstream publisher. If the upstream publisher finishes before collecting the specified number of elements, the publisher sends an array of only the items it received. This may be fewer than count elements. If the upstream publisher fails with an error, this publisher forwards the error to the downstream receiver instead of sending its output. In the example below, the collect(_:) operator emits one partial and two full arrays based on the requested collection size of 5: let numbers = (0...10) cancellable = numbers.publisher     .collect(5)     .sink { print("\($0), terminator: " "") }

// Prints "[0, 1, 2, 3, 4] [5, 6, 7, 8, 9] [10] " note: When this publisher receives a request for .max(n) elements, it requests .max(count * n) from the upstream publisher.

## See Also

### Reducing elements

- [collect()](combine/publisher/collect().md)
- [collect(_:options:)](combine/publisher/collect(_:options:).md)
- [Publishers.TimeGroupingStrategy](combine/publishers/timegroupingstrategy.md)
- [ignoreOutput()](combine/publisher/ignoreoutput().md)
- [reduce(_:_:)](combine/publisher/reduce(_:_:).md)
- [tryReduce(_:_:)](combine/publisher/tryreduce(_:_:).md)