Create Array of unique Arrays [Int] in swift

Question

So, I have loop, where I get [Int] and that Array may has only one element, may has several elements. That arrays may be the same and may be different.

I'd like to create Array of unique of arrays [Int]. How to do it? When I try to create by Set I see that

[Int] not hashable

my code:

for i in 0..<someData.count {

      someData?[i].db.value(forKey: "value") as! [Int] // here I get [Int]

      //here I'd like to create an array of unique arrays from from the line above
     }

it is kind of unclear what are you trying to do... could you make it clearer? — Ahmad F, Dec 28 '16 at 08:35
@VadimNikolaev You are adding all object of someData in same array? — Nirav D, Dec 28 '16 at 08:43
no, I can create new array. May be it will be true, and after that I'll that new array with all variants of arrays convert to `Set`? — Vadim Nikolaev, Dec 28 '16 at 08:45
Do you mean you want an array with arrays in it? You can do this `[[Int]]` — ntoonio, Dec 28 '16 at 08:52
@VadimNikolaev Check my answer if you are interested in the Hashable implementation — Niko Adrianus Yuwono, Dec 28 '16 at 09:54

score 1 · Accepted Answer · answered Dec 28 '16 at 09:36

var values:[Int] = [] {
    didSet{
        var uniqueValues = [Int]()
        var addedValues = Set<Int>()
        for value in values {
            if !addedValues.contains(value) {
                addedValues.insert(value)
                uniqueValues.append(value)
            }
        }
        values = uniqueValues
    }
}

values is your array which will hold only unique values.Hope this is what you are looking for.

score 1 · Answer 2 · answered Dec 28 '16 at 09:53

You can implement your own Hashable array too

import Foundation

internal struct HashableIntArray: Hashable {
    var value: [Int]
    var hashValue: Int { return value.reduce(0, +).hashValue }
}

internal func == (lhs:HashableIntArray,rhs: HashableIntArray) -> Bool {
    return lhs.value == rhs.value
}

let array = [HashableIntArray(value: [1,1,2]), HashableIntArray(value: [1,2,2]), HashableIntArray(value: [1,1,2])]

let set = Set(array)
print(array) // [HashableIntArray(value: [1, 1, 2]), HashableIntArray(value: [1, 2, 2]), HashableIntArray(value: [1, 1, 2])]
print(set) // [HashableIntArray(value: [1, 2, 2]), HashableIntArray(value: [1, 1, 2])]

Create Array of unique Arrays [Int] in swift

2 Answers2