StructureSwift5.9.0
UnicodeScalarView
A view of a string’s contents as a collection of Unicode scalar values.
@frozen struct UnicodeScalarViewYou can access a string’s view of Unicode scalar values by using its unicodeScalars property. Unicode scalar values are the 21-bit codes that are the basic unit of Unicode. Each scalar value is represented by a Unicode.Scalar instance and is equivalent to a UTF-32 code unit.
let flowers = "Flowers 💐"
for v in flowers.unicodeScalars {
print(v.value)
}
// 70
// 108
// 111
// 119
// 101
// 114
// 115
// 32
// 128144Some characters that are visible in a string are made up of more than one Unicode scalar value. In that case, a string’s unicodeScalars view contains more elements than the string itself.
let flag = "🇵🇷"
for c in flag {
print(c)
}
// 🇵🇷
for v in flag.unicodeScalars {
print(v.value)
}
// 127477
// 127479You can convert a String.UnicodeScalarView instance back into a string using the String type’s init(_:) initializer.
let favemoji = "My favorite emoji is 🎉"
if let i = favemoji.unicodeScalars.firstIndex(where: { $0.value >= 128 }) {
let asciiPrefix = String(favemoji.unicodeScalars[..<i])
print(asciiPrefix)
}
// Prints "My favorite emoji is "Citizens in Swift
Conformances
protocol BidirectionalCollectionA collection that supports backward as well as forward traversal.
protocol CollectionA sequence whose elements can be traversed multiple times, nondestructively, and accessed by an indexed subscript.
protocol CustomDebugStringConvertibleA type with a customized textual representation suitable for debugging purposes.
protocol CustomReflectableA type that explicitly supplies its own mirror.
protocol CustomStringConvertibleA type with a customized textual representation.
protocol RangeReplaceableCollectionA collection that supports replacement of an arbitrary subrange of elements with the elements of another collection.
protocol SendableA type whose values can safely be passed across concurrency domains by copying.
protocol SequenceA type that provides sequential, iterated access to its elements.
Members
init() Creates an empty view instance.
var customMirror: MirrorReturns a mirror that reflects the Unicode scalars view of a string.
var debugDescription: Stringvar description: Stringvar endIndex: String.UnicodeScalarView.IndexThe “past the end” position—that is, the position one greater than the last valid subscript argument.
var startIndex: String.UnicodeScalarView.IndexThe position of the first Unicode scalar value if the string is nonempty.
subscript(Range<String.UnicodeScalarView.Index>) -> String.UnicodeScalarView.SubSequence subscript(String.UnicodeScalarView.Index) -> Unicode.Scalar Accesses the Unicode scalar value at the given position.
func append(Unicode.Scalar) Appends the given Unicode scalar to the view.
func append<S>(contentsOf: S) Appends the Unicode scalar values in the given sequence to the view.
func distance(from: String.UnicodeScalarView.Index, to: String.UnicodeScalarView.Index) -> Int func index(String.UnicodeScalarView.Index, offsetBy: Int) -> String.UnicodeScalarView.Index func index(String.UnicodeScalarView.Index, offsetBy: Int, limitedBy: String.UnicodeScalarView.Index) -> String.UnicodeScalarView.Index? func index(after: String.UnicodeScalarView.Index) -> String.UnicodeScalarView.Index Returns the next consecutive location after
i.func index(before: String.UnicodeScalarView.Index) -> String.UnicodeScalarView.Index Returns the previous consecutive location before
i.func makeIterator() -> String.UnicodeScalarView.Iterator func replaceSubrange<C>(Range<String.UnicodeScalarView.Index>, with: C) Replaces the elements within the specified bounds with the given Unicode scalar values.
func reserveCapacity(Int) Reserves enough space in the view’s underlying storage to store the specified number of ASCII characters.
struct Iteratortypealias Indextypealias SubSequencevar customPlaygroundQuickLook: _PlaygroundQuickLook
Features
var first: Self.Element?The first element of the collection.
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.static func + <Other>(Other, Self) -> Self Creates a new collection by concatenating the elements of a sequence and a collection.
static func + <Other>(Self, Other) -> Self Creates a new collection by concatenating the elements of a collection and a sequence.
static func + <Other>(Self, Other) -> Self Creates a new collection by concatenating the elements of two collections.
static func += <Other>(inout Self, Other) Appends the elements of a sequence to a range-replaceable 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 applying(CollectionDifference<Self.Element>) -> Self? Applies the given difference to this collection.
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 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 Returns a new collection of the same type containing, in order, the elements of the original collection 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 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>((Self.Element) throws -> T) rethrows -> [T] Returns an array containing the results of mapping the given closure over the sequence’s 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 popLast() -> Self.Element? Removes and returns the last element of the collection.
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 removeLast() -> Self.Element Removes and returns the last element of the collection.
func removeLast(Int) Removes the specified number of elements from the end of the collection.
func reversed() -> ReversedCollection<Self> Returns a view presenting the elements of the collection 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) -> [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 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.