Structureswift-algorithms 1.2.1Algorithms
Chain2Sequence
A concatenation of two sequences with the same element type.
struct Chain2Sequence<Base1, Base2> where Base1 : Sequence, Base2 : Sequence, Base1.Element == Base2.ElementA concatenation of two sequences with the same element type.
struct Chain2Sequence<Base1, Base2> where Base1 : Sequence, Base2 : Sequence, Base1.Element == Base2.Elementimport AlgorithmsSwift Algorithms is an open-source package of sequence and collection algorithms, along with their related types.
protocol Sequence<Element>A type that provides sequential, iterated access to its elements.
associatedtype Element where Self.Element == Self.Iterator.ElementA type representing the sequence’s elements.
struct CycledSequence<Base> where Base : CollectionA collection wrapper that repeats the elements of a base collection.
struct CycledTimesCollection<Base> where Base : CollectionA collection wrapper that repeats the elements of a base collection for a finite number of times.
protocol BidirectionalCollection<Element> : Collection where Self.Indices : BidirectionalCollection, Self.SubSequence : BidirectionalCollectionA collection that supports backward as well as forward traversal.
func index(before i: Index) -> 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 firstRange<C>(of other: C) -> Range<Self.Index>? where C : Collection, Self.Element == C.Element Finds and returns the range of the first occurrence of a given collection within this collection.
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.
func startOfSuffix(while predicate: (Element) throws -> Bool) rethrows -> Index Returns the inclusive lower bound of the suffix of elements that satisfy the predicate.
func suffix(while predicate: (Element) throws -> Bool) rethrows -> SubSequence Returns a subsequence containing the elements from the end until predicate returns false and skipping the remaining elements.
func trimming(while predicate: (Element) throws -> Bool) rethrows -> SubSequence Returns a SubSequence formed by discarding all elements at the start and end of the collection which satisfy the given predicate.
func trimmingSuffix(while predicate: (Element) throws -> Bool) rethrows -> SubSequence Returns a SubSequence formed by discarding all elements at the end of the collection which satisfy the given predicate.
protocol CopyableA type whose values can be implicitly or explicitly copied.
protocol Escapablefunc makeIterator() -> Iterator struct IteratorThe iterator for a Chain2Sequence instance.
var lazy: LazySequence<Self> { get }A sequence containing the same elements as this sequence, but on which some operations, such as map and filter, are implemented lazily.
var underestimatedCount: Int { get }A value less than or equal to the number of elements in the sequence, calculated nondestructively.
func adjacentPairs() -> AdjacentPairsSequence<Self> Returns a sequence of overlapping adjacent pairs of the elements of this sequence.
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 compacted<Unwrapped>() -> CompactedSequence<Self, Unwrapped> where Self.Element == Unwrapped? Returns a new Sequence that iterates over every non-nil element from the original 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: (Self.Element) throws -> Bool) rethrows -> DropWhileSequence<Self> Returns a sequence by skipping the initial, consecutive elements that satisfy the given 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: (Self.Element) throws -> Bool) rethrows -> [Self.Element] Returns an array containing, in order, the elements of the sequence that satisfy the given predicate.
func first(where predicate: (Self.Element) throws -> Bool) rethrows -> Self.Element? Returns the first element of the sequence that satisfies the given predicate.
func firstNonNil<Result>(_ transform: (Element) throws -> Result?) rethrows -> Result? Returns the first non-nil result obtained from applying the given transformation to the elements of the sequence.
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 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 grouped<GroupKey>(by keyForValue: (Element) throws -> GroupKey) rethrows -> [GroupKey : [Element]] where GroupKey : Hashable Groups up elements of self into a new Dictionary, whose values are Arrays of grouped elements, each keyed by the group key returned by the given closure.
func interspersed(with separator: Element) -> InterspersedSequence<Self> Returns a sequence containing elements of this sequence with the given separator inserted in between each element.
func joined() -> FlattenSequence<Self> Returns the elements of this sequence of sequences, concatenated.
func joined<Separator>(by separator: Separator) -> JoinedBySequence<Self, Separator> where Separator : Collection, Separator.Element == Self.Element.Element Returns the concatenation of the elements in this sequence of sequences, inserting the given separator between each sequence.
func joined(by separator: Element.Element) -> JoinedBySequence<Self, CollectionOfOne<Element.Element>> Returns the concatenation of the elements in this sequence of sequences, inserting the given separator between each sequence.
func joined<Separator>(by separator: (Element, Element) throws -> Separator) rethrows -> [Element.Element] where Separator : Sequence, Separator.Element == Self.Element.Element Returns the concatenation of the elements in this sequence of sequences, inserting the separator produced by the closure between each sequence.
func joined(by separator: (Element, Element) throws -> Element.Element) rethrows -> [Element.Element] Returns the concatenation of the elements in this sequence of sequences, inserting the separator produced by the closure between each sequence.
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 keyed<Key>(by keyForValue: (Element) throws -> Key) rethrows -> [Key : Element] where Key : Hashable Creates a new Dictionary from the elements of self, keyed by the results returned by the given keyForValue closure.
func keyed<Key>(by keyForValue: (Element) throws -> Key, resolvingConflictsWith resolve: (Key, Element, Element) throws -> Element) rethrows -> [Key : Element] where Key : Hashable Creates a new Dictionary from the elements of self, keyed by the results returned by the given keyForValue closure. As the dictionary is built, the initializer calls the resolve closure with the current and new values for any duplicate keys. Pass a closure as resolve that returns the value to use in the resulting dictionary: The closure can choose between the two values, combine them to produce a new value, or even throw an error.
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.
@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.
func max(count: Int) -> [Element] Returns the largest elements of this sequence.
func max(count: Int, sortedBy areInIncreasingOrder: (Element, Element) throws -> Bool) rethrows -> [Element] Returns the largest elements of this sequence, as sorted by the given predicate.
@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 min(count: Int) -> [Element] Returns the smallest elements of this sequence.
func min(count: Int, sortedBy areInIncreasingOrder: (Element, Element) throws -> Bool) rethrows -> [Element] Returns the smallest elements of this sequence, as sorted by the given predicate.
func minAndMax() -> (min: Element, max: Element)? Returns both the minimum and maximum elements in the sequence.
func minAndMax(by areInIncreasingOrder: (Element, Element) throws -> Bool) rethrows -> (min: Element, max: Element)? Returns both the minimum and maximum elements in the sequence, using the given predicate as the comparison between elements.
func partitioned(by predicate: (Element) throws -> Bool) rethrows -> (falseElements: [Element], trueElements: [Element]) Returns two arrays containing the elements of the sequence that don’t and do satisfy the given predicate, respectively.
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: (Self.Element) throws -> Bool) rethrows -> [Self.Element] Returns a sequence containing the initial, consecutive elements that satisfy the given predicate.
func randomSample(count k: Int) -> [Element] Randomly selects the specified number of elements from this sequence.
func randomSample<G>(count k: Int, using rng: inout G) -> [Element] where G : RandomNumberGenerator Randomly selects the specified number of elements from this sequence.
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 reductions(_ transform: (Element, Element) throws -> Element) rethrows -> [Element] Returns an array containing the accumulated results of combining the elements of the sequence using the given closure.
func reductions<Result>(_ initial: Result, _ transform: (Result, Element) throws -> Result) rethrows -> [Result] Returns an array containing the accumulated results of combining the elements of the sequence using the given closure.
func reductions<Result>(into initial: Result, _ transform: (inout Result, Element) throws -> Void) rethrows -> [Result] Returns an array containing the accumulated results 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 striding(by step: Int) -> StridingSequence<Self> Returns a sequence stepping through the elements every step starting at the first value. Any remainders of the stride will be trimmed.
func suffix(_ maxLength: Int) -> [Self.Element] Returns a subsequence, up to the given maximum length, containing the final elements of the sequence.
func uniqued() -> UniquedSequence<Self, Element> Returns a sequence with only the unique elements of this sequence, in the order of the first occurrence of each unique element.
func uniqued<Subject>(on projection: (Element) throws -> Subject) rethrows -> [Element] where Subject : Hashable Returns an array with the unique elements of this sequence (as determined by the given projection), in the order of the first occurrence of each unique element.
func withContiguousStorageIfAvailable<R>(_ body: (UnsafeBufferPointer<Self.Element>) throws -> R) rethrows -> R? func flatMap<ElementOfResult>(_ transform: (Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult] func scan(_ transform: (Element, Element) throws -> Element) rethrows -> [Element] func scan<Result>(_ initial: Result, _ transform: (Result, Element) throws -> Result) rethrows -> [Result] func scan<Result>(into initial: Result, _ transform: (inout Result, Element) throws -> Void) rethrows -> [Result] protocol RandomAccessCollection<Element> : BidirectionalCollection where Self.Indices : RandomAccessCollection, Self.SubSequence : RandomAccessCollectionA 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> : SequenceA sequence whose elements can be traversed multiple times, nondestructively, and accessed by an indexed subscript.
var endIndex: Index { get }var startIndex: Index { get }subscript(i: Index) -> Base1.Element { get } func distance(from start: Index, to end: Index) -> Int func index(_ i: Index, offsetBy distance: Int) -> Index func index(_ i: Index, offsetBy distance: Int, limitedBy limit: Index) -> Index? func index(after i: Index) -> Index struct IndexA position in a Chain2Sequence instance.
var count: Int { get }The number of elements in the collection.
var indices: DefaultIndices<Self> { get }The indices that are valid for subscripting the collection, in ascending order.
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 chunked(by belongInSameGroup: (Element, Element) throws -> Bool) rethrows -> [SubSequence] Returns a collection of subsequences of this collection, chunked by the given predicate.
func chunked<Subject>(on projection: (Element) throws -> Subject) rethrows -> [(Subject, SubSequence)] where Subject : Equatable Returns a collection of subsequences of this collection, chunked by grouping elements that project to equal values.
func chunks(ofCount count: Int) -> ChunksOfCountCollection<Self> Returns a collection of subsequences, each with up to the specified length.
func combinations(ofCount k: Int) -> CombinationsSequence<Self> Returns a collection of combinations of this collection’s elements, with each combination having the specified number of elements.
func combinations<R>(ofCount kRange: R) -> CombinationsSequence<Self> where R : RangeExpression, R.Bound == Int Returns a collection of combinations of this collection’s elements, with each combination having the specified number of elements.
func compacted<Unwrapped>() -> CompactedCollection<Self, Unwrapped> where Self.Element == Unwrapped? Returns a new Collection that iterates over every non-nil element from the original Collection.
func contains<C>(_ other: C) -> Bool where C : Collection, Self.Element == C.Element Returns a Boolean value indicating whether the collection contains the given sequence.
func cycled() -> CycledSequence<Self> Returns a sequence that repeats the elements of this collection forever.
func cycled(times: Int) -> CycledTimesCollection<Self> Returns a sequence that repeats the elements of this collection the specified number of times.
func distance(from start: Self.Index, to end: Self.Index) -> Int Returns the distance between two indices.
func endOfPrefix(while predicate: (Element) throws -> Bool) rethrows -> Index Returns the exclusive upper bound of the prefix of elements that satisfy the predicate.
func evenlyChunked(in count: Int) -> EvenlyChunkedCollection<Self> Returns a collection of evenly divided consecutive subsequences of this collection.
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 firstRange<C>(of other: C) -> Range<Self.Index>? where C : Collection, Self.Element == C.Element Finds and returns the range of the first occurrence of a given collection within this collection.
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 indexed() -> IndexedCollection<Self> Returns a collection of pairs (i, x), where i represents an index of the collection, and x represents an element.
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 joined<Separator>(by separator: Separator) -> JoinedByCollection<Self, Separator> where Separator : Collection, Separator.Element == Self.Element.Element Returns the concatenation of the elements in this collection of collections, inserting the given separator between each collection.
func joined(by separator: Element.Element) -> JoinedByCollection<Self, CollectionOfOne<Element.Element>> Returns the concatenation of the elements in this collection of collections, inserting the given separator between each collection.
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 max(count: Int) -> [Element] Returns the largest elements of this collection.
func min(count: Int) -> [Element] Returns the smallest elements of this collection.
func partitioningIndex(where belongsInSecondPartition: (Element) throws -> Bool) rethrows -> Index Returns the start index of the partition of a collection that matches the given predicate.
func permutations(ofCount k: Int? = nil) -> PermutationsSequence<Self> Returns a collection of the permutations of this collection of the specified length.
func permutations<R>(ofCount kRange: R) -> PermutationsSequence<Self> where R : RangeExpression, R.Bound == Int Returns a collection of the permutations of this collection with lengths in the specified range.
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 randomSample<G>(count k: Int, using rng: inout G) -> [Element] where G : RandomNumberGenerator Randomly selects the specified number of elements from this collection.
func randomStableSample(count k: Int) -> [Element] Randomly selects the specified number of elements from this collection, maintaining their relative order.
func randomStableSample<G>(count k: Int, using rng: inout G) -> [Element] where G : RandomNumberGenerator Randomly selects the specified number of elements from this collection, maintaining their relative order.
func ranges<C>(of other: C) -> [Range<Self.Index>] where C : Collection, Self.Element == C.Element Finds and returns the ranges of the all occurrences of a given sequence within the collection.
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 split<C>(separator: C, maxSplits: Int = .max, omittingEmptySubsequences: Bool = true) -> [Self.SubSequence] where C : Collection, Self.Element == C.Element Returns the longest possible subsequences of the collection, in order, around elements equal to the given separator.
func suffix(from start: Self.Index) -> Self.SubSequence Returns a subsequence from the specified position to the end of the collection.
func trimmingPrefix<Prefix>(_ prefix: Prefix) -> Self.SubSequence where Prefix : Sequence, Self.Element == Prefix.Element Returns a new collection of the same type by removing prefix from the start of the collection.
func trimmingPrefix(while predicate: (Element) throws -> Bool) rethrows -> SubSequence Returns a SubSequence formed by discarding all elements at the start of the collection which satisfy the given predicate.
func uniquePermutations(ofCount k: Int? = nil) -> UniquePermutationsSequence<Self> Returns a sequence of the unique permutations of this sequence of the specified length.
func uniquePermutations<R>(ofCount kRange: R) -> UniquePermutationsSequence<Self> where R : RangeExpression, R.Bound == Int Returns a collection of the unique permutations of this sequence with lengths in the specified range.
func windows(ofCount count: Int) -> WindowsOfCountCollection<Self> Returns a collection of all the overlapping slices of a given size.
func index(of element: Self.Element) -> Self.Index? Returns the first index where the specified value appears in the collection.