LazySequence
A sequence containing the same elements as a Base
sequence, but on which some operations such as map
and filter
are implemented lazily.
@frozen struct LazySequence<Base> where Base : Sequence
A sequence containing the same elements as a Base
sequence, but on which some operations such as map
and filter
are implemented lazily.
@frozen struct LazySequence<Base> where Base : Sequence
import Swift
protocol Sequence<Element>
A type that provides sequential, iterated access to its elements.
protocol BidirectionalCollection<Element> : Collection where Self.Indices : BidirectionalCollection, Self.SubSequence : BidirectionalCollection
A collection that supports backward as well as forward traversal.
func index(before i: LazySequence<Base>.Index) -> LazySequence<Base>.Index
var last: Self.Element? { get }
The last element of the collection.
func difference<C>(from other: C) -> CollectionDifference<Self.Element> where C : BidirectionalCollection, Self.Element == C.Element
Returns the difference needed to produce this collection’s ordered elements from the given collection.
func difference<C>(from other: C, by areEquivalent: (C.Element, Self.Element) -> Bool) -> CollectionDifference<Self.Element> where C : BidirectionalCollection, Self.Element == C.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 distance(from start: Self.Index, to end: Self.Index) -> Int
func formIndex(before i: inout Self.Index)
func index(_ i: Self.Index, offsetBy distance: Int) -> Self.Index
func index(_ i: Self.Index, offsetBy distance: Int, limitedBy limit: Self.Index) -> Self.Index?
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 predicate: (Self.Element) throws -> Bool) rethrows -> Self.Element?
Returns the last element of the sequence that satisfies the given predicate.
func lastIndex(of element: Self.Element) -> Self.Index?
Returns the last index where the specified value appears in the collection.
func lastIndex(where predicate: (Self.Element) throws -> Bool) rethrows -> Self.Index?
Returns the index of the last element in the collection that matches the given predicate.
protocol Copyable
A type whose values can be implicitly or explicitly copied.
protocol Escapable
protocol LazySequenceProtocol : Sequence
A sequence on which normally-eager sequence operations are implemented lazily.
var elements: LazySequence<Base>.Elements { get }
The Base
(presumably non-lazy) sequence from which self
was created.
var underestimatedCount: Int { get }
func makeIterator() -> LazySequence<Base>.Iterator
typealias Element = Base.Element
typealias Elements = Base
typealias Iterator = Base.Iterator
var lazy: LazySequence<Self.Elements> { get }
func allSatisfy(_ predicate: (Self.Element) throws -> Bool) rethrows -> Bool
Returns a Boolean value indicating whether every element of a sequence satisfies a given predicate.
func compactMap<ElementOfResult>(_ transform: (Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult]
Returns an array containing the non-nil
results of calling the given transformation with each element of this sequence.
func compactMap<ElementOfResult>(_ transform: @escaping (Self.Elements.Element) -> ElementOfResult?) -> LazyMapSequence<LazyFilterSequence<LazyMapSequence<Self.Elements, ElementOfResult?>>, ElementOfResult>
Returns the non-nil
results of mapping the given transformation over this sequence.
func contains(_ element: Self.Element) -> Bool
Returns a Boolean value indicating whether the sequence contains the given element.
func contains(where predicate: (Self.Element) throws -> Bool) rethrows -> Bool
Returns a Boolean value indicating whether the sequence contains an element that satisfies the given predicate.
func count<E>(where predicate: (Self.Element) throws(E) -> Bool) throws(E) -> Int where E : Error
Returns the number of elements in the sequence that satisfy the given predicate.
func drop(while predicate: @escaping (Self.Elements.Element) -> Bool) -> LazyDropWhileSequence<Self.Elements>
Returns a lazy sequence that skips any initial elements that satisfy predicate
.
func dropFirst(_ k: Int = 1) -> DropFirstSequence<Self>
Returns a sequence containing all but the given number of initial elements.
func dropLast(_ k: Int = 1) -> [Self.Element]
Returns a sequence containing all but the given number of final elements.
func elementsEqual<OtherSequence>(_ other: OtherSequence) -> Bool where OtherSequence : Sequence, Self.Element == OtherSequence.Element
Returns a Boolean value indicating whether this sequence and another sequence contain the same elements in the same order.
func elementsEqual<OtherSequence>(_ other: OtherSequence, by areEquivalent: (Self.Element, OtherSequence.Element) throws -> Bool) rethrows -> Bool where OtherSequence : Sequence
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(_ isIncluded: @escaping (Self.Elements.Element) -> Bool) -> LazyFilterSequence<Self.Elements>
Returns the elements of self
that satisfy isIncluded
.
func first(where predicate: (Self.Element) throws -> Bool) rethrows -> Self.Element?
Returns the first element of the sequence that satisfies the given predicate.
func flatMap<SegmentOfResult>(_ transform: (Self.Element) throws -> SegmentOfResult) rethrows -> [SegmentOfResult.Element] where SegmentOfResult : Sequence
Returns an array containing the concatenated results of calling the given transformation with each element of this sequence.
func flatMap<SegmentOfResult>(_ transform: @escaping (Self.Elements.Element) -> SegmentOfResult) -> LazySequence<FlattenSequence<LazyMapSequence<Self.Elements, SegmentOfResult>>> where SegmentOfResult : Sequence
Returns the concatenated results of mapping the given transformation over this sequence.
func forEach(_ body: (Self.Element) throws -> Void) rethrows
Calls the given closure on each element in the sequence in the same order as a for
-in
loop.
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> where Separator : Sequence, Separator.Element == Self.Element.Element
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>(_ other: OtherSequence) -> Bool where OtherSequence : Sequence, Self.Element == OtherSequence.Element
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>(_ other: OtherSequence, by areInIncreasingOrder: (Self.Element, Self.Element) throws -> Bool) rethrows -> Bool where OtherSequence : Sequence, Self.Element == OtherSequence.Element
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, E>(_ transform: (Self.Element) throws(E) -> T) throws(E) -> [T] where E : Error
Returns an array containing the results of mapping the given closure over the sequence’s elements.
func map<U>(_ transform: @escaping (Self.Element) -> U) -> LazyMapSequence<Self.Elements, U>
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.
@warn_unqualified_access func max() -> Self.Element?
Returns the maximum element in the sequence.
@warn_unqualified_access func max(by areInIncreasingOrder: (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.
@warn_unqualified_access func min() -> Self.Element?
Returns the minimum element in the sequence.
@warn_unqualified_access func min(by areInIncreasingOrder: (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(_ maxLength: Int) -> PrefixSequence<Self>
Returns a sequence, up to the specified maximum length, containing the initial elements of the sequence.
func prefix(while predicate: @escaping (Self.Elements.Element) -> Bool) -> LazyPrefixWhileSequence<Self.Elements>
Returns a lazy sequence of the initial consecutive elements that satisfy predicate
.
func reduce<Result>(_ initialResult: Result, _ nextPartialResult: (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 initialResult: Result, _ updateAccumulatingResult: (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 generator: inout T) -> [Self.Element] where T : RandomNumberGenerator
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 areInIncreasingOrder: (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 = Int.max, omittingEmptySubsequences: Bool = true, whereSeparator isSeparator: (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 = Int.max, omittingEmptySubsequences: Bool = true) -> [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: PossiblePrefix) -> Bool where PossiblePrefix : Sequence, Self.Element == PossiblePrefix.Element
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: PossiblePrefix, by areEquivalent: (Self.Element, PossiblePrefix.Element) throws -> Bool) rethrows -> Bool where PossiblePrefix : Sequence
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(_ maxLength: Int) -> [Self.Element]
Returns a subsequence, up to the given maximum length, containing the final elements of the sequence.
func withContiguousStorageIfAvailable<R>(_ body: (UnsafeBufferPointer<Self.Element>) throws -> R) rethrows -> R?
func flatMap<ElementOfResult>(_ transform: (Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult]
func flatMap<ElementOfResult>(_ transform: @escaping (Self.Elements.Element) -> ElementOfResult?) -> LazyMapSequence<LazyFilterSequence<LazyMapSequence<Self.Elements, ElementOfResult?>>, ElementOfResult>
Returns the non-nil
results of mapping the given transformation over this sequence.
protocol Sendable
protocol RandomAccessCollection<Element> : BidirectionalCollection where Self.Indices : RandomAccessCollection, Self.SubSequence : RandomAccessCollection
A collection that supports efficient random-access index traversal.
func index(_ i: Self.Index, offsetBy distance: Int, limitedBy limit: Self.Index) -> Self.Index?
Returns an index that is the specified distance from the given index, unless that distance is beyond a given limiting index.
protocol Collection<Element> : Sequence
A sequence whose elements can be traversed multiple times, nondestructively, and accessed by an indexed subscript.
protocol LazyCollectionProtocol : Collection, LazySequenceProtocol where Self.Elements : Collection
var count: Int { get }
Returns the number of elements.
var endIndex: LazySequence<Base>.Index { get }
The collection’s “past the end” position—that is, the position one greater than the last valid subscript argument.
var indices: LazySequence<Base>.Indices { get }
var isEmpty: Bool { get }
A Boolean value indicating whether the collection is empty.
var startIndex: LazySequence<Base>.Index { get }
The position of the first element in a non-empty collection.
subscript(position: LazySequence<Base>.Index) -> LazySequence<Base>.Element { get }
Accesses the element at position
.
func distance(from start: LazySequence<Base>.Index, to end: LazySequence<Base>.Index) -> Int
func index(_ i: LazySequence<Base>.Index, offsetBy n: Int) -> LazySequence<Base>.Index
func index(_ i: LazySequence<Base>.Index, offsetBy n: Int, limitedBy limit: LazySequence<Base>.Index) -> LazySequence<Base>.Index?
func index(after i: LazySequence<Base>.Index) -> LazySequence<Base>.Index
typealias Index = Base.Index
A type that represents a valid position in the collection.
typealias Indices = Base.Indices
typealias SubSequence = Slice<LazySequence<Base>>
var count: Int { get }
The number of elements in the collection.
var isEmpty: Bool { get }
A Boolean value indicating whether the collection is empty.
subscript<R>(r: R) -> Self.SubSequence where R : RangeExpression, Self.Index == R.Bound { get }
Accesses the contiguous subrange of the collection’s elements specified by a range expression.
subscript(x: (UnboundedRange_) -> ()) -> Self.SubSequence { get }
subscript(subranges: RangeSet<Self.Index>) -> DiscontiguousSlice<Self> { get }
Accesses a view of this collection with the elements at the given indices.
subscript(bounds: Range<Self.Index>) -> Slice<Self> { get }
Accesses a contiguous subrange of the collection’s elements.
func distance(from start: Self.Index, to end: Self.Index) -> Int
Returns the distance between two indices.
func firstIndex(of element: Self.Element) -> Self.Index?
Returns the first index where the specified value appears in the collection.
func firstIndex(where predicate: (Self.Element) throws -> Bool) rethrows -> Self.Index?
Returns the first index in which an element of the collection satisfies the given predicate.
func formIndex(_ i: inout Self.Index, offsetBy distance: Int)
Offsets the given index by the specified distance.
func formIndex(_ i: inout Self.Index, offsetBy distance: Int, limitedBy limit: Self.Index) -> Bool
Offsets the given index by the specified distance, or so that it equals the given limiting index.
func formIndex(after i: inout Self.Index)
Replaces the given index with its successor.
func index(_ i: Self.Index, offsetBy distance: Int) -> Self.Index
Returns an index that is the specified distance from the given index.
func index(_ i: Self.Index, offsetBy distance: Int, limitedBy limit: Self.Index) -> Self.Index?
Returns an index that is the specified distance from the given index, unless that distance is beyond a given limiting index.
func indices(of element: Self.Element) -> RangeSet<Self.Index>
Returns the indices of all the elements that are equal to the given element.
func indices(where predicate: (Self.Element) throws -> Bool) rethrows -> RangeSet<Self.Index>
Returns the indices of all the elements that match the given predicate.
func map<T, E>(_ transform: (Self.Element) throws(E) -> T) throws(E) -> [T] where E : Error
Returns an array containing the results of mapping the given closure over the sequence’s elements.
func prefix(through position: Self.Index) -> Self.SubSequence
Returns a subsequence from the start of the collection through the specified position.
func prefix(upTo end: 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 generator: inout T) -> Self.Element? where T : RandomNumberGenerator
Returns a random element of the collection, using the given generator as a source for randomness.
func removingSubranges(_ subranges: RangeSet<Self.Index>) -> DiscontiguousSlice<Self>
Returns a collection of the elements in this collection that are not represented by the given range set.
func split(separator: Self.Element, maxSplits: Int = Int.max, omittingEmptySubsequences: Bool = true) -> [Self.SubSequence]
Returns the longest possible subsequences of the collection, in order, around elements equal to the given element.
func suffix(from start: Self.Index) -> Self.SubSequence
Returns a subsequence from the specified position to the end of the collection.
func index(of element: Self.Element) -> Self.Index?
Returns the first index where the specified value appears in the collection.