---
title: "mapFeatures(_:)"
framework: swift
role: symbol
role_heading: Instance Method
path: "swift/lazysequence/mapfeatures(_:)"
---

# mapFeatures(_:)

Returns a lazy sequence where the elements of the result are computed each time they are read by calling transform function on the feature of an annotated feature.

## Declaration

```swift
func mapFeatures<Input, Output, Annotation>(_ transform: @escaping (Input) -> Output) -> LazyMapSequence<Base, AnnotatedFeature<Output, Annotation>> where Base.Element == AnnotatedFeature<Input, Annotation>
```