# LazySequenceProtocol Implementations ## Topics ### Instance Properties [`var elements: Self`](/documentation/Swift/ReversedCollection/elements-swift.property) Identical to `self`. ### Instance Methods [`func compactMap((Self.Elements.Element) -> ElementOfResult?) -> LazyMapSequence>, ElementOfResult>`](/documentation/Swift/ReversedCollection/compactMap(_:)-45kvo) Returns the non-`nil` results of mapping the given transformation over this sequence. [`func filter((Self.Elements.Element) -> Bool) -> LazyFilterSequence`](/documentation/Swift/ReversedCollection/filter(_:)-4t9rn) Returns the elements of `self` that satisfy `isIncluded`. [`func flatMap((Self.Elements.Element) -> SegmentOfResult) -> LazySequence>>`](/documentation/Swift/ReversedCollection/flatMap(_:)-4wxgx) Returns the concatenated results of mapping the given transformation over this sequence. [`func flatMap((Self.Elements.Element) -> ElementOfResult?) -> LazyMapSequence>, ElementOfResult>`](/documentation/Swift/ReversedCollection/flatMap(_:)-81zng) Returns the non-`nil` results of mapping the given transformation over this sequence. [`func joined() -> LazySequence>`](/documentation/Swift/ReversedCollection/joined()-2x3z5) Returns a lazy sequence that concatenates the elements of this sequence of sequences. [`func map((Self.Element) -> U) -> LazyMapSequence`](/documentation/Swift/ReversedCollection/map(_:)-88nu3) Returns a `LazyMapSequence` over this `Sequence`. The elements of the result are computed lazily, each time they are read, by calling `transform` function on a base element. ### Type Aliases [`typealias Elements`](/documentation/Swift/ReversedCollection/Elements) A `Sequence` that can contain the same elements as this one, possibly with a simpler type. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)