var first: Self.Element?
The first element of the collection.
var indices: DefaultIndices<Self>
The indices that are valid for subscripting the collection, in ascending order.
var isEmpty: Bool
A Boolean value indicating whether the collection is empty.
var lazy: LazySequence<Self>
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
A value less than or equal to the number of elements in the collection.
func adjacentPairs() -> AdjacentPairsCollection<Self>
Returns a collection of overlapping adjacent pairs of the elements of this collection.
func allSatisfy((Self.Element) throws -> Bool) rethrows -> Bool
Returns a Boolean value indicating whether every element of a sequence satisfies a given predicate.
func chunked(by: (Element, Element) throws -> Bool) rethrows -> [SubSequence]
Returns a collection of subsequences of this collection, chunked by the given predicate.
func chunked<Subject>(on: (Element) throws -> Subject) rethrows -> [(Subject, SubSequence)]
Returns a collection of subsequences of this collection, chunked by grouping elements that project to equal values.
func chunks(ofCount: Int) -> ChunksOfCountCollection<Self>
Returns a collection of subsequences, each with up to the specified length.
func combinations(ofCount: Int) -> CombinationsSequence<Self>
Returns a collection of combinations of this collection’s elements, with each combination having the specified number of elements.
func compactMap<ElementOfResult>((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>
Returns a new Sequence
that iterates over every non-nil element from the original Sequence
.
func compacted<Unwrapped>() -> CompactedCollection<Self, Unwrapped>
Returns a new Collection
that iterates over every non-nil element from the original Collection
.
func contains(Self.Element) -> Bool
Returns a Boolean value indicating whether the sequence contains the given element.
func contains<C>(C) -> Bool
Returns a Boolean value indicating whether the collection contains the given sequence.
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 count<E>(where: (Self.Element) throws(E) -> Bool) throws(E) -> Int
Returns the number of elements in the sequence that satisfy the given predicate.
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 drop(while: (Self.Element) throws -> Bool) rethrows -> Self.SubSequence
Returns a subsequence by skipping elements while predicate
returns true
and returning the remaining elements.
func dropFirst(Int) -> Self.SubSequence
Returns a subsequence containing all but the given number of initial elements.
func dropLast(Int) -> Self.SubSequence
Returns a subsequence containing all but the specified 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 endOfPrefix(while: (Element) throws -> Bool) rethrows -> Index
Returns the exclusive upper bound of the prefix of elements that satisfy the predicate.
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 evenlyChunked(in: Int) -> EvenlyChunkedCollection<Self>
Returns a collection of evenly divided consecutive subsequences of this collection.
func filter((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: (Self.Element) throws -> Bool) rethrows -> Self.Element?
Returns the first element of the sequence that satisfies the given predicate.
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 firstNonNil<Result>((Element) throws -> Result?) rethrows -> Result?
Returns the first non-nil
result obtained from applying the given transformation to the elements of the sequence.
func firstRange<C>(of: C) -> Range<Self.Index>?
Finds and returns the range of the first occurrence of a given collection within this collection.
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 forEach((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 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 formIndex(after: inout Self.Index)
Replaces the given index with its successor.
func grouped<GroupKey>(by: (Element) throws -> GroupKey) rethrows -> [GroupKey : [Element]]
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 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: Self.Element) -> RangeSet<Self.Index>
Returns the indices of all the elements that are equal to the given element.
func indices(where: (Self.Element) throws -> Bool) rethrows -> RangeSet<Self.Index>
Returns the indices of all the elements that match the given predicate.
func interspersed(with: Element) -> InterspersedSequence<Self>
Returns a sequence containing elements of this sequence with the given separator inserted in between each element.
func joined(by: 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 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 keyed<Key>(by: (Element) throws -> Key) rethrows -> [Key : Element]
Creates a new Dictionary from the elements of self
, keyed by the results returned by the given keyForValue
closure.
func keyed<Key>(by: (Element) throws -> Key, resolvingConflictsWith: (Key, Element, Element) throws -> Element) rethrows -> [Key : Element]
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>(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 makeIterator() -> IndexingIterator<Self>
Returns an iterator over the elements of the collection.
func map<T, E>((Self.Element) throws(E) -> T) throws(E) -> [T]
Returns an array containing the results of mapping the given closure over the sequence’s elements.
func map<T, E>((Self.Element) throws(E) -> T) throws(E) -> [T]
Returns an array containing the results of mapping the given closure over the sequence’s elements.
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 max(count: Int) -> [Element]
Returns the largest elements of this sequence.
func max(count: Int) -> [Element]
Returns the largest elements of this collection.
func max(count: Int, sortedBy: (Element, Element) throws -> Bool) rethrows -> [Element]
Returns the largest elements of this collection, as sorted by the given predicate.
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 min(count: Int) -> [Element]
Returns the smallest elements of this sequence.
func min(count: Int) -> [Element]
Returns the smallest elements of this collection.
func min(count: Int, sortedBy: (Element, Element) throws -> Bool) rethrows -> [Element]
Returns the smallest elements of this collection, 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: (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: (Element) throws -> Bool) rethrows -> (falseElements: [Element], trueElements: [Element])
Returns two arrays containing, in order, the elements of the collection that do and don’t satisfy the given predicate.
func partitioningIndex(where: (Element) throws -> Bool) rethrows -> Index
Returns the start index of the partition of a collection that matches the given predicate.
func permutations(ofCount: Int?) -> PermutationsSequence<Self>
Returns a collection of the permutations of this collection of the specified length.
func prefix(Int) -> Self.SubSequence
Returns a subsequence, up to the specified maximum length, containing the initial elements of the collection.
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 prefix(while: (Self.Element) throws -> Bool) rethrows -> Self.SubSequence
Returns a subsequence containing the initial elements until predicate
returns false
and skipping the remaining elements.
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 randomSample(count: Int) -> [Element]
Randomly selects the specified number of elements from this collection.
func randomSample<G>(count: Int, using: inout G) -> [Element]
Randomly selects the specified number of elements from this sequence.
func randomSample<G>(count: Int, using: inout G) -> [Element]
Randomly selects the specified number of elements from this collection.
func randomStableSample(count: Int) -> [Element]
Randomly selects the specified number of elements from this collection, maintaining their relative order.
func randomStableSample<G>(count: Int, using: inout G) -> [Element]
Randomly selects the specified number of elements from this collection, maintaining their relative order.
func ranges<C>(of: C) -> [Range<Self.Index>]
Finds and returns the ranges of the all occurrences of a given sequence within the collection.
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 reductions((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>(Result, (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: Result, (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 removingSubranges(RangeSet<Self.Index>) -> DiscontiguousSlice<Self>
Returns a collection of the elements in this collection that are not represented by the given range set.
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 -> [Self.SubSequence]
Returns the longest possible subsequences of the collection, in order, that don’t contain elements satisfying the given predicate.
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 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 split<C>(separator: C, maxSplits: Int, omittingEmptySubsequences: Bool) -> [Self.SubSequence]
Returns the longest possible subsequences of the collection, in order, around elements equal to the given separator.
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 striding(by: Int) -> StridingCollection<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(Int) -> Self.SubSequence
Returns a subsequence, up to the given maximum length, containing the final elements of the collection.
func suffix(from: Self.Index) -> Self.SubSequence
Returns a subsequence from the specified position to the end of the collection.
func trimmingPrefix<Prefix>(Prefix) -> Self.SubSequence
Returns a new collection of the same type by removing prefix
from the start of the collection.
func trimmingPrefix(while: (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: Int?) -> UniquePermutationsSequence<Self>
Returns a sequence of the unique permutations of this sequence of the specified length.
func uniquePermutations<R>(ofCount: R) -> UniquePermutationsSequence<Self>
Returns a collection of the unique permutations of this sequence with lengths in the specified range.
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: (Element) throws -> Subject) rethrows -> [Element]
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 windows(ofCount: Int) -> WindowsOfCountCollection<Self>
Returns a collection of all the overlapping slices of a given size.
func withContiguousStorageIfAvailable<R>((UnsafeBufferPointer<Self.Element>) throws -> R) rethrows -> R?