How can I get array object of unique value using Higher Order Functions of swift

Question

Ex.

Input: var array: [Int] = [1, 2, 3, 1, 3, 4, 2, 1]

Output:

[[1, 1, 1], [2, 2], [3, 3], [4]]

Possible duplicate of [Removing duplicate elements from an array in Swift](https://stackoverflow.com/questions/25738817/removing-duplicate-elements-from-an-array-in-swift) — Maximelc, Aug 12 '19 at 09:31

score 4 · Accepted Answer · edited Aug 12 '19 at 12:08

4

A solution with Dictionary(grouping:by:)

let array = [1, 2, 3, 1, 3, 4, 2, 1]
let output = Dictionary(grouping: array, by: {$0})
    .values
    .sorted(by: { $0[0] < $1[0] })

edited Aug 12 '19 at 12:08

Alexander

answered Aug 12 '19 at 09:31

vadian

Thank you. It's really help me lots. – Trupesh Vaghasiya Aug 12 '19 at 09:37
Hello @vadian it's return Dictionary not array. – Trupesh Vaghasiya Aug 12 '19 at 09:47
No, it returns array. – vadian Aug 12 '19 at 09:48
Yes, I am not use sorted that's why. Thank you. – Trupesh Vaghasiya Aug 12 '19 at 09:49
I wonder how this compares to `Dictionary(grouping: array, by: { $0 }) .sorted(by: { $0.key < $1.key }) .map { $0.value }`, performance-wise – Alexander Aug 12 '19 at 10:29
@Alexander Feel free to run a test. – vadian Aug 12 '19 at 12:00
@vadian I'll check it out when I have time. Side note, would you be okay if I reformatted that long line, so it fits the post better? – Alexander Aug 12 '19 at 12:02
@Alexander Reformat how? – vadian Aug 12 '19 at 12:06
@vadian See my edit. Feel free to revert – Alexander Aug 12 '19 at 12:08
@Alexander I don't mind. – vadian Aug 12 '19 at 12:09

1 Answers1