LazyMapSequence
A Sequence whose elements consist of those in a Base Sequence passed through a transform function returning Element. These elements are computed lazily, each time they’re read, by calling the transform function on a base element.
@frozen struct LazyMapSequence<Base, Element> where Base : SequenceCitizens in Swift
Members
Citizens in Swift
where Base:SequenceConformances
protocol LazySequenceProtocolA sequence on which normally-eager sequence operations are implemented lazily.
protocol SequenceA type that provides sequential, iterated access to its elements.
Members
var underestimatedCount: IntA value less than or equal to the number of elements in the sequence, calculated nondestructively.
func makeIterator() -> LazyMapSequence<Base, Element>.Iterator Returns an iterator over the elements of this sequence.
func map<ElementOfResult>((Element) -> ElementOfResult) -> LazyMapSequence<Base, ElementOfResult> struct Iterator
Features
var lazy: Self.Elementsfunc allSatisfy((Self.Element) throws -> Bool) rethrows -> Bool Returns a Boolean value indicating whether every element of a sequence satisfies a given predicate.
func compactMap<ElementOfResult>((Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult] Returns an array containing the non-
nilresults of calling the given transformation with each element of this sequence.func compactMap<ElementOfResult>((Self.Elements.Element) -> ElementOfResult?) -> LazyMapSequence<LazyFilterSequence<LazyMapSequence<Self.Elements, ElementOfResult?>>, ElementOfResult> Returns the non-
nilresults of mapping the given transformation over this sequence.func contains(Self.Element) -> Bool Returns a Boolean value indicating whether the sequence contains the given element.
func contains(where: (Self.Element) throws -> Bool) rethrows -> Bool Returns a Boolean value indicating whether the sequence contains an element that satisfies the given predicate.
func drop(while: (Self.Elements.Element) -> Bool) -> LazyDropWhileSequence<Self.Elements> Returns a lazy sequence that skips any initial elements that satisfy
predicate.func dropFirst(Int) -> DropFirstSequence<Self> Returns a sequence containing all but the given number of initial elements.
func dropLast(Int) -> [Self.Element] Returns a sequence containing all but the given number of final elements.
func elementsEqual<OtherSequence>(OtherSequence) -> Bool Returns a Boolean value indicating whether this sequence and another sequence contain the same elements in the same order.
func elementsEqual<OtherSequence>(OtherSequence, by: (Self.Element, OtherSequence.Element) throws -> Bool) rethrows -> Bool Returns a Boolean value indicating whether this sequence and another sequence contain equivalent elements in the same order, using the given predicate as the equivalence test.
func enumerated() -> EnumeratedSequence<Self> Returns a sequence of pairs (n, x), where n represents a consecutive integer starting at zero and x represents an element of the sequence.
func filter((Self.Elements.Element) -> Bool) -> LazyFilterSequence<Self.Elements> Returns the elements of
selfthat satisfyisIncluded.func first(where: (Self.Element) throws -> Bool) rethrows -> Self.Element? Returns the first element of the sequence that satisfies the given predicate.
func flatMap<SegmentOfResult>((Self.Element) throws -> SegmentOfResult) rethrows -> [SegmentOfResult.Element] Returns an array containing the concatenated results of calling the given transformation with each element of this sequence.
func flatMap<SegmentOfResult>((Self.Elements.Element) -> SegmentOfResult) -> LazySequence<FlattenSequence<LazyMapSequence<Self.Elements, SegmentOfResult>>> Returns the concatenated results of mapping the given transformation over this sequence.
func forEach((Self.Element) throws -> Void) rethrows Calls the given closure on each element in the sequence in the same order as a
for-inloop.func joined() -> FlattenSequence<Self> Returns the elements of this sequence of sequences, concatenated.
func joined() -> LazySequence<FlattenSequence<Self.Elements>> Returns a lazy sequence that concatenates the elements of this sequence of sequences.
func joined<Separator>(separator: Separator) -> JoinedSequence<Self> Returns the concatenated elements of this sequence of sequences, inserting the given separator between each element.
func joined(separator: String) -> String Returns a new string by concatenating the elements of the sequence, adding the given separator between each element.
func lexicographicallyPrecedes<OtherSequence>(OtherSequence) -> Bool Returns a Boolean value indicating whether the sequence precedes another sequence in a lexicographical (dictionary) ordering, using the less-than operator (
<) to compare elements.func lexicographicallyPrecedes<OtherSequence>(OtherSequence, by: (Self.Element, Self.Element) throws -> Bool) rethrows -> Bool Returns a Boolean value indicating whether the sequence precedes another sequence in a lexicographical (dictionary) ordering, using the given predicate to compare elements.
func map<T>((Self.Element) throws -> T) rethrows -> [T] Returns an array containing the results of mapping the given closure over the sequence’s elements.
func map<U>((Self.Element) -> U) -> LazyMapSequence<Self.Elements, U> Returns a
LazyMapSequenceover thisSequence. The elements of the result are computed lazily, each time they are read, by callingtransformfunction on a base element.func max() -> Self.Element? Returns the maximum element in the sequence.
func max(by: (Self.Element, Self.Element) throws -> Bool) rethrows -> Self.Element? Returns the maximum element in the sequence, using the given predicate as the comparison between elements.
func min() -> Self.Element? Returns the minimum element in the sequence.
func min(by: (Self.Element, Self.Element) throws -> Bool) rethrows -> Self.Element? Returns the minimum element in the sequence, using the given predicate as the comparison between elements.
func prefix(Int) -> PrefixSequence<Self> Returns a sequence, up to the specified maximum length, containing the initial elements of the sequence.
func prefix(while: (Self.Elements.Element) -> Bool) -> LazyPrefixWhileSequence<Self.Elements> Returns a lazy sequence of the initial consecutive elements that satisfy
predicate.func reduce<Result>(Result, (Result, Self.Element) throws -> Result) rethrows -> Result Returns the result of combining the elements of the sequence using the given closure.
func reduce<Result>(into: Result, (inout Result, Self.Element) throws -> ()) rethrows -> Result Returns the result of combining the elements of the sequence using the given closure.
func reversed() -> [Self.Element] Returns an array containing the elements of this sequence in reverse order.
func shuffled() -> [Self.Element] Returns the elements of the sequence, shuffled.
func shuffled<T>(using: inout T) -> [Self.Element] Returns the elements of the sequence, shuffled using the given generator as a source for randomness.
func sorted() -> [Self.Element] Returns the elements of the sequence, sorted.
func sorted(by: (Self.Element, Self.Element) throws -> Bool) rethrows -> [Self.Element] Returns the elements of the sequence, sorted using the given predicate as the comparison between elements.
func split(maxSplits: Int, omittingEmptySubsequences: Bool, whereSeparator: (Self.Element) throws -> Bool) rethrows -> [ArraySlice<Self.Element>] Returns the longest possible subsequences of the sequence, in order, that don’t contain elements satisfying the given predicate. Elements that are used to split the sequence are not returned as part of any subsequence.
func split(separator: Self.Element, maxSplits: Int, omittingEmptySubsequences: Bool) -> [ArraySlice<Self.Element>] Returns the longest possible subsequences of the sequence, in order, around elements equal to the given element.
func starts<PossiblePrefix>(with: PossiblePrefix) -> Bool Returns a Boolean value indicating whether the initial elements of the sequence are the same as the elements in another sequence.
func starts<PossiblePrefix>(with: PossiblePrefix, by: (Self.Element, PossiblePrefix.Element) throws -> Bool) rethrows -> Bool Returns a Boolean value indicating whether the initial elements of the sequence are equivalent to the elements in another sequence, using the given predicate as the equivalence test.
func suffix(Int) -> [Self.Element] Returns a subsequence, up to the given maximum length, containing the final elements of the sequence.
func flatMap<ElementOfResult>((Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult] func flatMap<ElementOfResult>((Self.Elements.Element) -> ElementOfResult?) -> LazyMapSequence<LazyFilterSequence<LazyMapSequence<Self.Elements, ElementOfResult?>>, ElementOfResult> Returns the non-
nilresults of mapping the given transformation over this sequence.
Citizens in Swift
where Base:RandomAccessCollectionConformances
protocol RandomAccessCollectionA collection that supports efficient random-access index traversal.
Citizens in Swift
where Base:BidirectionalCollectionConformances
protocol BidirectionalCollectionA collection that supports backward as well as forward traversal.
Members
func formIndex(before: inout LazyMapSequence<Base, Element>.Index) func index(before: LazyMapSequence<Base, Element>.Index) -> LazyMapSequence<Base, Element>.Index A value less than or equal to the number of elements in the collection.
Features
var last: Self.Element?The last element of the collection.
func difference<C>(from: C) -> CollectionDifference<Self.Element> Returns the difference needed to produce this collection’s ordered elements from the given collection.
func difference<C>(from: C, by: (C.Element, Self.Element) -> Bool) -> CollectionDifference<Self.Element> Returns the difference needed to produce this collection’s ordered elements from the given collection, using the given predicate as an equivalence test.
func joined(separator: String) -> String Returns a new string by concatenating the elements of the sequence, adding the given separator between each element.
func last(where: (Self.Element) throws -> Bool) rethrows -> Self.Element? Returns the last element of the sequence that satisfies the given predicate.
func lastIndex(of: Self.Element) -> Self.Index? Returns the last index where the specified value appears in the collection.
func lastIndex(where: (Self.Element) throws -> Bool) rethrows -> Self.Index? Returns the index of the last element in the collection that matches the given predicate.
Citizens in Swift
where Base:CollectionConformances
protocol CollectionA sequence whose elements can be traversed multiple times, nondestructively, and accessed by an indexed subscript.
protocol LazyCollectionProtocol
Members
var count: IntThe number of elements in the collection.
var endIndex: Base.Indexvar indices: LazyMapSequence<Base, Element>.Indicesvar isEmpty: BoolA Boolean value indicating whether the collection is empty.
var startIndex: Base.Indexsubscript(Range<Base.Index>) -> LazyMapSequence<Base, Element>.SubSequence subscript(Base.Index) -> Element Accesses the element at
position.func distance(from: LazyMapSequence<Base, Element>.Index, to: LazyMapSequence<Base, Element>.Index) -> Int func formIndex(after: inout LazyMapSequence<Base, Element>.Index) func index(LazyMapSequence<Base, Element>.Index, offsetBy: Int) -> LazyMapSequence<Base, Element>.Index func index(LazyMapSequence<Base, Element>.Index, offsetBy: Int, limitedBy: LazyMapSequence<Base, Element>.Index) -> LazyMapSequence<Base, Element>.Index? func index(after: LazyMapSequence<Base, Element>.Index) -> LazyMapSequence<Base, Element>.Index func map<ElementOfResult>((Element) -> ElementOfResult) -> LazyMapCollection<Base, ElementOfResult> typealias Indextypealias Indicestypealias SubSequence
Features
func firstIndex(of: Self.Element) -> Self.Index? Returns the first index where the specified value appears in the collection.
func firstIndex(where: (Self.Element) throws -> Bool) rethrows -> Self.Index? Returns the first index in which an element of the collection satisfies the given predicate.
func formIndex(inout Self.Index, offsetBy: Int) Offsets the given index by the specified distance.
func formIndex(inout Self.Index, offsetBy: Int, limitedBy: Self.Index) -> Bool Offsets the given index by the specified distance, or so that it equals the given limiting index.
func map<T>((Self.Element) throws -> T) rethrows -> [T] Returns an array containing the results of mapping the given closure over the sequence’s elements.
func prefix(through: Self.Index) -> Self.SubSequence Returns a subsequence from the start of the collection through the specified position.
func prefix(upTo: Self.Index) -> Self.SubSequence Returns a subsequence from the start of the collection up to, but not including, the specified position.
func randomElement() -> Self.Element? Returns a random element of the collection.
func randomElement<T>(using: inout T) -> Self.Element? Returns a random element of the collection, using the given generator as a source for randomness.
func split(separator: Self.Element, maxSplits: Int, omittingEmptySubsequences: Bool) -> [Self.SubSequence] Returns the longest possible subsequences of the collection, in order, around elements equal to the given element.
func suffix(from: Self.Index) -> Self.SubSequence Returns a subsequence from the specified position to the end of the collection.
func index(of: Self.Element) -> Self.Index? Returns the first index where the specified value appears in the collection.