How to map a set in Swift

Overview

In Swift, we can use the map{} method on a set to return an array that corresponds to what was specified in a block. For example, we can use this method to return the results of dividing each number value of a set by 2.

Syntax

set.map{closure}
Syntax of the "map{}" method in Swift

Parameter value

Closure: This value creates a condition or a closure over the set's elements. It also gives us access to each element of the set.

Return value

This method returns an array.

Example

// create some sets
let names: Set = ["Alicia", "Bethany", "Chris", "Diana", "Eric"]
let numbers: Set = [1, 2, 3, 4, 5, 7, 8, 9, 10]
// use the map{}
print(names.map{$0.count}) // return array of length of names
print(numbers.map{$0 * 2}) // return array of numbers multiplied by 2

Explanation

  • Lines 2–3: We create some sets and initialize them with values.
  • Line 6: We map the names set and return an array that contains the count of characters of each name.
  • Line 7: We use the map{} method to return an array of elements of the numbers set, where each element in the array has been multiplied by 2.

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