Generic Instance Method


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


func map<T>(_ transform: (Iterator.Element) throws -> T) rethrows -> [T]



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.


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

Complexity: O(n), where n is the length of the sequence.