---
title: LazyFilterSequence
framework: swift
role: symbol
role_heading: Structure
path: swift/lazyfiltersequence
---

# LazyFilterSequence

A sequence whose elements consist of the elements of some base sequence that also satisfy a given predicate.

## Declaration

```swift
@frozen struct LazyFilterSequence<Base> where Base : Sequence
```

## Overview

Overview note: s.lazy.filter { ... }, for an arbitrary sequence s, is a LazyFilterSequence.

## Topics

### Instance Properties

- [underestimatedCount](swift/lazyfiltersequence/underestimatedcount.md)

### Instance Methods

- [filter(_:)](swift/lazyfiltersequence/filter(_:).md)
- [formIndex(_:offsetBy:)](swift/lazyfiltersequence/formindex(_:offsetby:).md)
- [formIndex(_:offsetBy:limitedBy:)](swift/lazyfiltersequence/formindex(_:offsetby:limitedby:).md)

### Default Implementations

- [BidirectionalCollection Implementations](swift/lazyfiltersequence/bidirectionalcollection-implementations.md)
- [Collection Implementations](swift/lazyfiltersequence/collection-implementations.md)
- [LazySequenceProtocol Implementations](swift/lazyfiltersequence/lazysequenceprotocol-implementations.md)
- [Sequence Implementations](swift/lazyfiltersequence/sequence-implementations.md)

## Relationships

### Conforms To

- [BidirectionalCollection](swift/bidirectionalcollection.md)
- [Collection](swift/collection.md)
- [Copyable](swift/copyable.md)
- [Escapable](swift/escapable.md)
- [LazyCollectionProtocol](swift/lazycollectionprotocol.md)
- [LazySequenceProtocol](swift/lazysequenceprotocol.md)
- [Sequence](swift/sequence.md)

## See Also

### Lazy Wrappers

- [LazySequence](swift/lazysequence.md)
- [LazyMapSequence](swift/lazymapsequence.md)
- [LazyPrefixWhileSequence](swift/lazyprefixwhilesequence.md)
- [LazyDropWhileSequence](swift/lazydropwhilesequence.md)
- [LazyCollection](swift/lazycollection.md)
- [LazyDropWhileCollection](swift/lazydropwhilecollection.md)
- [LazyFilterCollection](swift/lazyfiltercollection.md)
- [LazyMapCollection](swift/lazymapcollection.md)
- [LazyPrefixWhileCollection](swift/lazyprefixwhilecollection.md)