LazyPrefixWhileSequence
A sequence whose elements consist of the initial consecutive elements of some base sequence that satisfy a given predicate.
@frozen struct LazyPrefixWhileSequence<Base> where Base : Sequence
typealias Element
A type representing the sequence’s elements.
typealias Elements
A Sequence
that can contain the same elements as this one, possibly with a simpler type.
typealias SubSequence
A collection representing a contiguous subrange of this collection’s elements. The subsequence shares indices with the original collection.
subscript(Range<Self.Index>) -> Slice<Self>
Accesses a contiguous subrange of the collection’s elements.
subscript((UnboundedRange_) -> ()) -> Self.SubSequence
subscript<R>(R) -> Self.SubSequence
Accesses the contiguous subrange of the collection’s elements specified by a range expression.
subscript(LazyPrefixWhileSequence<Base>.Index) -> LazyPrefixWhileSequence<Base>.Element
Accesses the element at the specified position.
var last: Self.Element?
The last element of the collection.
var count: Int
The number of elements in the collection.
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 underestimatedCount: Int
A value less than or equal to the number of elements in the collection.
var lazy: LazyCollection<Self.Elements>
var lazy: Self.Elements
var endIndex: LazyPrefixWhileSequence<Base>.Index
The collection’s “past the end” position—that is, the position one greater than the last valid subscript argument.
var startIndex: LazyPrefixWhileSequence<Base>.Index
The position of the first element in a nonempty collection.
var elements: Self
Identical to self
.
var lazy: LazySequence<Self.Elements>
var lazy: Self.Elements
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 sequence, calculated nondestructively.
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 distance(from: Self.Index, to: Self.Index) -> Int
func formIndex(before: inout Self.Index)
Replaces the given index with its predecessor.
func index(Self.Index, offsetBy: Int) -> Self.Index
func index(Self.Index, offsetBy: Int, limitedBy: 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: (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 distance(from: Self.Index, to: Self.Index) -> Int
Returns the distance between two indices.
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 formIndex(after: inout Self.Index)
Replaces the given index with its successor.
func index(Self.Index, offsetBy: Int) -> Self.Index
Returns an index that is the specified distance from the given 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 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(after: LazyPrefixWhileSequence<Base>.Index) -> LazyPrefixWhileSequence<Base>.Index
Returns the position immediately after the given index.
func index(before: LazyPrefixWhileSequence<Base>.Index) -> LazyPrefixWhileSequence<Base>.Index
Returns the position immediately before the given index.
func makeIterator() -> LazyPrefixWhileSequence<Base>.Iterator
Returns an iterator over the elements of this sequence.
func compactMap<ElementOfResult>((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 drop(while: (Self.Elements.Element) -> Bool) -> LazyDropWhileSequence<Self.Elements>
Returns a lazy sequence that skips any initial elements that satisfy predicate
.
func filter((Self.Elements.Element) -> Bool) -> LazyFilterSequence<Self.Elements>
Returns the elements of self
that satisfy isIncluded
.
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 joined() -> LazySequence<FlattenSequence<Self.Elements>>
Returns a lazy sequence that concatenates the elements of this sequence of sequences.
func map<U>((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.
func prefix(while: (Self.Elements.Element) -> Bool) -> LazyPrefixWhileSequence<Self.Elements>
Returns a lazy sequence of the initial consecutive elements that satisfy predicate
.
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-nil
results 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 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 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 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 joined() -> FlattenSequence<Self>
Returns the elements of this sequence of sequences, concatenated.
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 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 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 withContiguousStorageIfAvailable<R>((UnsafeBufferPointer<Self.Element>) throws -> R) rethrows -> R?
Executes a closure on the sequence’s contiguous storage.
struct Index
A position in a LazyPrefixWhileCollection
or LazyPrefixWhileBidirectionalCollection
instance.
struct Iterator
An iterator over the initial elements traversed by a base iterator that satisfy a given predicate.
BidirectionalCollection
When Base
conforms to BidirectionalCollection
Collection
When Base
conforms to Collection
LazyCollectionProtocol
When Base
conforms to Collection
LazySequenceProtocol
When Base
conforms to Sequence
Sequence
When Base
conforms to Sequence
func index(of: Self.Element) -> Self.Index?
Returns the first index where the specified value appears in the collection.
Deprecated since Swift 5.0
func flatMap<ElementOfResult>((Self.Elements.Element) -> ElementOfResult?) -> LazyMapSequence<LazyFilterSequence<LazyMapSequence<Self.Elements, ElementOfResult?>>, ElementOfResult>
Returns the non-nil
results of mapping the given transformation over this sequence.
Deprecated since Swift 4.1
func flatMap<ElementOfResult>((Self.Element) throws -> ElementOfResult?) rethrows -> [ElementOfResult]
Deprecated since Swift 4.1