public struct Sampling<Base: Collection, Selection: Collection>
where Selection.Element == Base.Index
extension Sampling: SamplingProtocol
extension Sampling: Collection
extension Sampling: BidirectionalCollection
where Selection: BidirectionalCollection
extension Sampling: RandomAccessCollection
where Selection: RandomAccessCollection
何らかの基本コレクションから、指定された順序で要素を遅延選択します。