Store and organize data using arrays, dictionaries, sets, and other data structures.
Collections
Topics
Arrays and Dictionaries
struct ArrayAn ordered, random-access collection.
struct DictionaryA collection whose elements are key-value pairs.
Sets
struct SetAn unordered collection of unique elements.
protocol OptionSet A type that presents a mathematical set interface to a bit set.
Ranges
Create a collection of all the values in a range by using the half-open (..<) and closed (...) range operators.
static func ..< (Self, Self) -> Range<Self>Returns a half-open range that contains its lower bound but not its upper bound.
struct RangeA half-open interval from a lower bound up to, but not including, an upper bound.
static func ... (Self, Self) -> ClosedRange<Self> Returns a closed range that contains both of its bounds.
struct ClosedRange An interval from a lower bound up to, and including, an upper bound.
Strides
Create a stride that steps over values between two boundaries using the stride(from: and stride(from: functions.
func stride<T>(from: T, to: T, by: T.Stride) -> StrideTo<T> Returns a sequence from a starting value to, but not including, an end value, stepping by the specified amount.
func stride<T>(from: T, through: T, by: T.Stride) -> StrideThrough<T> Returns a sequence from a starting value toward, and possibly including, an end value, stepping by the specified amount.
Special-Use Collections
These collections can store zero, one, or many of the same element.
func repeatElement <T>(T, count: Int) -> Repeated<T>Creates a collection containing the specified number of the given element.
struct CollectionOfOne A collection containing a single element.
struct EmptyCollection A collection whose element type is Element but that is always empty.
struct KeyValuePairs A lightweight collection of key-value pairs.
typealias DictionaryLiteral DeprecatedDynamic Sequences
func sequence<T>(first: T, next: (T) -> T?) -> UnfoldFirstSequence<T> Returns a sequence formed from first and repeated lazy applications of next.
func sequence<T, State>(state: State, next: (inout State) -> T?) -> UnfoldSequence<T, State> Returns a sequence formed from repeated lazy applications of next to a mutable state.
Joint Iteration
func zip<Sequence1, Sequence2>(Sequence1, Sequence2) -> Zip2Sequence<Sequence1, Sequence2>Creates a sequence of pairs built out of two underlying sequences.
Advanced Collection Topics
Sequence and Collection Protocols
Write generic code that works with any collection, or build your own collection types.
Supporting Types
Use wrappers, indices, and iterators in operations like slicing, flattening, and reversing a collection.
Managed Buffers
Build your own buffer-backed collection types.
See Also
Values and Collections
Numbers and Basic Values
Model data with numbers, Boolean values, and other fundamental types.
Strings and Text
Work with text using Unicode-safe strings.