Structureswift 6.0.1Swift
CollectionOfOne
A collection containing a single element.
@frozen struct CollectionOfOne<Element>You can use a CollectionOfOne instance when you need to efficiently represent a single value as a collection. For example, you can add a single element to an array by using a CollectionOfOne instance with the concatenation operator (+):
let a = [1, 2, 3, 4]
let toAdd = 100
let b = a + CollectionOfOne(toAdd)
// b == [1, 2, 3, 4, 100]Citizens in Swift
Types
struct IteratorAn iterator that produces one or zero instances of an element.
Typealiases
Type members
init(Element) Creates an instance containing just the given element.
Instance members
var count: IntThe number of elements in the collection, which is always one.
var customMirror: Mirrorvar debugDescription: StringA textual representation of the collection, suitable for debugging.
var endIndex: CollectionOfOne<Element>.IndexThe “past the end” position—that is, the position one greater than the last valid subscript argument.
var startIndex: CollectionOfOne<Element>.IndexThe position of the first element.
subscript(Range<Int>) -> CollectionOfOne<Element>.SubSequence subscript(Int) -> Element Accesses the element at the specified position.
func index(after: CollectionOfOne<Element>.Index) -> CollectionOfOne<Element>.Index Returns the position immediately after the given index.
func index(before: CollectionOfOne<Element>.Index) -> CollectionOfOne<Element>.Index Returns the position immediately before the given index.
func makeIterator() -> CollectionOfOne<Element>.Iterator Returns an iterator over the elements of this collection.
Citizens in Swift
Conformances
Citizens in Swift
Conformances
protocol BidirectionalCollection<Element>A collection that supports backward as well as forward traversal.
protocol Collection<Element>A sequence whose elements can be traversed multiple times, nondestructively, and accessed by an indexed subscript.
protocol CopyableA type whose values can be implicitly or explicitly copied.
protocol CustomDebugStringConvertibleA type with a customized textual representation suitable for debugging purposes.
protocol CustomReflectableA type that explicitly supplies its own mirror.
protocol Escapableprotocol MutableCollection<Element>A collection that supports subscript assignment.
protocol RandomAccessCollection<Element>A collection that supports efficient random-access index traversal.
protocol Sequence<Element>A type that provides sequential, iterated access to its elements.
Instance features
var first: Self.Element?The first element of the collection.
var isEmpty: BoolA Boolean value indicating whether the collection is empty.
var last: Self.Element?The last element of the collection.
var lazy: LazySequence<Self>A sequence containing the same elements as this sequence, but on which some operations, such as
mapandfilter, are implemented lazily.var underestimatedCount: IntA value less than or equal to the number of elements in the collection.
subscript<R>(R) -> Self.SubSequence subscript((UnboundedRange_) -> ()) -> Self.SubSequence subscript(Range<Self.Index>) -> Slice<Self> Accesses a contiguous subrange of the collection’s elements.
subscript<R>(R) -> Self.SubSequence Accesses the contiguous subrange of the collection’s elements specified by a range expression.
subscript((UnboundedRange_) -> ()) -> Self.SubSequence subscript(RangeSet<Self.Index>) -> DiscontiguousSlice<Self> Accesses a view of this collection with the elements at the given indices.
subscript(Range<Self.Index>) -> Slice<Self> Accesses a contiguous subrange of the collection’s elements.
func 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 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 count<E>(where: (Self.Element)throws Returns the number of elements in the sequence that satisfy the given predicate.
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 drop(while: (Self.Element) throws -> Bool) rethrows -> Self.SubSequence Returns a subsequence by skipping elements while
predicatereturnstrueand 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 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.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 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-inloop.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 formIndex(before: inout Self.Index) func index(Self.Index, offsetBy: Int, limitedBy: 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: 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 joined() -> FlattenSequence<Self> Returns the elements of this sequence of sequences, concatenated.
func joined(separator: String) -> String Returns a new string by concatenating the elements of the sequence, adding the given separator between each element.
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 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.
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, E>((Self.Element)throws Returns an array containing the results of mapping the given closure over the sequence’s elements.
func map<T, E>((Self.Element)throws 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 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 moveSubranges(RangeSet<Self.Index>, to: Self.Index) -> Range<Self.Index> Moves the elements in the given subranges to just before the element at the specified index.
func partition(by: (Self.Element) throws -> Bool) rethrows -> Self.Index Reorders the elements of the collection such that all the elements that match the given predicate are after all the elements that don’t match.
func partition(by: (Self.Element) throws -> Bool) rethrows -> Self.Index Reorders the elements of the collection such that all the elements that match the given predicate are after all the elements that don’t match.
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
predicatereturnsfalseand 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 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 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 reverse() Reverses the elements of the collection in place.
func reversed() -> ReversedCollection<Self> Returns a view presenting the elements of the collection in reverse order.
func shuffle() Shuffles the collection in place.
func shuffle<T>(using: inout T) Shuffles the collection in place, using the given generator as a source for randomness.
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 sort() Sorts the collection in place.
func sort(by: (Self.Element, Self.Element) throws -> Bool) rethrows Sorts the collection in place, using the given predicate as the comparison between elements.
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 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.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 swapAt(Self.Index, Self.Index) Exchanges the values at the specified indices of the collection.
func withContiguousMutableStorageIfAvailable<R>((inout UnsafeMutableBufferPointer<Self.Element>) throws -> R) rethrows -> R? func withContiguousStorageIfAvailable<R>((UnsafeBufferPointer<Self.Element>) throws -> R) rethrows -> R?
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func flatMap<ElementOfResult>((Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult] func index(of: Self.Element) -> Self.Index? Returns the first index where the specified value appears in the collection.
Available in FoundationEssentials
where Element == UInt8Conformances
protocol ContiguousBytesIndicates that the conforming type is a contiguous collection of raw bytes whose underlying storage is directly accessible by withUnsafeBytes.