Is it possible to remove duplicate values from Array with nil values

Question

Array can be any type like

let myArray1 = [ 1, 2, 3, 1, 2, 1, 3, nil, 1, nil]

let myArray2 = [ 1, 2.0, 1, 3, 1.0, nil]

After removing duplicate values from the array, the new array should be:

Output -

 [ 1, 2, 3, nil ]

please check related questions : https://stackoverflow.com/questions/25738817/removing-duplicate-elements-from-an-array — Sharad Chauhan, Jan 17 '18 at 09:35
i tried this link as well https://stackoverflow.com/questions/25738817/removing-duplicate-elements-from-an-array — Pratik Panchal, Jan 17 '18 at 09:36
Is there any special reason for keeping nil also ?. asking because there might be a better way — Prashant Tukadiya, Jan 17 '18 at 10:20
@PrashantTukadiya yes for getting nil value i perform some operation so. — Pratik Panchal, Jan 18 '18 at 13:25

score 3 · Answer 1 · answered Jan 17 '18 at 10:14

3

@Daniel's solution as a generic function:

func uniqueElements<T: Equatable>(of array: [T?]) -> [T?] {
    return array.reduce([T?]()) { (result, item) -> [T?] in
        if result.contains(where: {$0 == item}) {
            return result
        }
        return result + [item]
    }
}

let array = [1,2,3,1,2,1,3,nil,1,nil]

let r = uniqueElements(of: array) // [1,2,3,nil]

answered Jan 17 '18 at 10:14

Gereon

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Alternate is that possible using extension of sequence.? – Pratik Panchal Jan 17 '18 at 10:38
Would be interested to see that myself, I haven't found a way to express this so far. – Gereon Jan 17 '18 at 12:18

score 2 · Answer 2 · answered Jan 17 '18 at 09:51

2

You can use this reduce to remove duplicated entries:

myArray.reduce([Int?]()) { (result, item) -> [Int?] in
    if result.contains(where: {$0 == item}) {
        return result
    }
    return result + [item]
}

output: [1, 2, 3, nil]

answered Jan 17 '18 at 09:51

Daniel

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type is not specify it can be dynamic like int, double or it can be String of array – Pratik Panchal Jan 17 '18 at 09:58
Array can be Any Type like 1) let myArray1 = [1,2,3,1,2,1,3,nil,1,nil] or 2) let myArray2 = [1,2.0,1,3,1.0,nil] – Pratik Panchal Jan 17 '18 at 10:05

score 2 · Answer 3 · answered Jan 17 '18 at 10:12

2

Please check this code, I have used NSArray after getting filtered array you can convert into swift array

    let arr = [1, 1, 1, 2, 2, 3, 4, 5, 6, nil, nil, 8]

    let filterSet = NSSet(array: arr as NSArray as! [NSObject])
    let filterArray = filterSet.allObjects as NSArray  //NSArray
    print("Filter Array:\(filterArray)")

answered Jan 17 '18 at 10:12

Bhupesh

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This does not preserve the order of elements. – Gereon Jan 17 '18 at 10:18

Is it possible to remove duplicate values from Array with nil values

3 Answers3