iOS Get Rid Of Duplicates In Arrays

[Garut]

I have an app I am trying to build that contains player objects in an array but I am trying to make sure there are no duplicates. My objects come by way of a notification from another VC. How do I remove duplicates in my favArr?

class FavouriteManager {


   


   


    static let shared = FavouriteManager()


   


    var favArr : [CurrentPlayer] = []


   





   


    func add(_ player: CurrentPlayer) {


        NotificationCenter.default.post(


            name: .passFavNotification,


            object: player


        )


       





        favArr.append(player)


       

        //algo I tried but did not work.
        for player in favArr {


            if !favArr.contains(player) {


                favArr.append(player)


            }


    }
}
}

extension Notification.Name {


    static let passFavNotification = Notification.Name("pass")


}


class HockeyDetailVC: UITableViewController {



[B]     var[/B] item: CurrentPlayer?


     override func viewDidLoad() {
   
       NotificationCenter.default.addObserver(self,


        selector: #selector(handleFavNotification(notification:)),


        name: .passFavNotification,


        object: nil)


    }


   


    @objc func handleFavNotification(notification:Notification){


            if let theFav = notification.object as? CurrentPlayer {


                item = theFav


            }


        }
}

 

[casperes1996]

If you don't want duplicates does it not make more sense to start out using a Set instead of an array? They automatically enforce there being no duplicate entires.

If you want to stick to an array you'll have to scan through the array every time you're about to add one to see if it's already there

 

[Garut]

Alright I figured it out just needed to add this extension.

extension Array where Element: Hashable {


    func removingDuplicates() -> [Element] {


        var addedDict = [Element: Bool]()


        


        return filter {


            addedDict.updateValue(true, forKey: $0) == nil


        }


    }


    


    mutating func removeDuplicates() {


        self = self.removingDuplicates()


    }


}

 

[casperes1996]

Alright I figured it out just needed to add this extension.

extension Array where Element: Hashable {


    func removingDuplicates() -> [Element] {


        var addedDict = [Element: Bool]()


       


        return filter {


            addedDict.updateValue(true, forKey: $0) == nil


        }


    }


   


    mutating func removeDuplicates() {


        self = self.removingDuplicates()


    }


}

Sure thing - go for what works. But this feels a bit like a hack, if all you want to achieve is not having duplicates, you can just use a Set instead of an array.
Or if your elements conform to Equatable, you can use something similar to your first post; Before ever appending anything you can check if the array already contains the element. - But you may be trying to add and then remove duplicates for some reason rather than avoiding having them in the first place? Or am I missing something else?

 

[cmaier]

Sure thing - go for what works. But this feels a bit like a hack, if all you want to achieve is not having duplicates, you can just use a Set instead of an array.
Or if your elements conform to Equatable, you can use something similar to your first post; Before ever appending anything you can check if the array already contains the element. - But you may be trying to add and then remove duplicates for some reason rather than avoiding having them in the first place? Or am I missing something else?

Agreed. Definitely an inefficient approach.