Generic Instance Method

map(_:)

Returns an array containing the results of mapping the given closure over the sequence’s elements.

Declaration

func map<T>(_ transform: (Bound) throws -> T) rethrows -> [T]
Available when Bound conforms to Strideable and Bound.Stride conforms to SignedInteger.

Parameters

transform

A mapping closure. transform accepts an element of this sequence as its parameter and returns a transformed value of the same or of a different type.

Return Value

An array containing the transformed elements of this sequence.

Discussion

In this example, map is used first to convert the names in the array to lowercase strings and then to count their characters.

let cast = ["Vivien", "Marlon", "Kim", "Karl"]
let lowercaseNames = cast.map { $0.lowercased() }
// 'lowercaseNames' == ["vivien", "marlon", "kim", "karl"]
let letterCounts = cast.map { $0.count }
// 'letterCounts' == [6, 6, 3, 4]

See Also

Transforming a Range's Elements

func compactMap<ElementOfResult>((Bound) -> ElementOfResult?) -> [ElementOfResult]

Returns an array containing the non-nil results of calling the given transformation with each element of this sequence.

func flatMap<SegmentOfResult>((Bound) -> SegmentOfResult) -> [SegmentOfResult.Element]

Returns an array containing the concatenated results of calling the given transformation with each element of this sequence.

func flatMap<ElementOfResult>((Bound) -> ElementOfResult?) -> [ElementOfResult]
Deprecated
func reduce<Result>(Result, (Result, Bound) -> Result) -> Result

Returns the result of combining the elements of the sequence using the given closure.

func reduce<Result>(into: Result, (inout Result, Bound) -> ()) -> Result

Returns the result of combining the elements of the sequence using the given closure.

var lazy: LazySequence<Range<Bound>>

A sequence containing the same elements as this sequence, but on which some operations, such as map and filter, are implemented lazily.