Removing Duplicates From Array of Custom Objects Swift

Question

I have a custom class defined as follows :

class DisplayMessage : NSObject {
var id : String?
var partner_image : UIImage?
var partner_name : String?
var la         


        

Answer 1

Create a free duplicate version of an Array, using equality comparisons based on a given key

public extension Sequence {

    public func uniq(by getIdentifier: (Iterator.Element) -> Id) -> [Iterator.Element] {
        var ids = Set()
        return self.reduce([]) { uniqueElements, element in
            if ids.insert(getIdentifier(element)).inserted {
                return uniqueElements + CollectionOfOne(element)
            }
            return uniqueElements
        }
    }


   public func uniq(by keyPath: KeyPath) -> [Iterator.Element] {
      return self.uniq(by: { $0[keyPath: keyPath] })
   }
}

public extension Sequence where Iterator.Element: Hashable {

    var uniq: [Iterator.Element] {
        return self.uniq(by: { (element) -> Iterator.Element in
            return element
        })
    }

}

Usage

let numbers =  [1,2,3,4,5,6,7,1,1,1,]
let cars = [Car(id:1), Car(id:1), Car(id:2)]

numbers.uniq
cars.uniq(by: { $0.id})
cars.uniq(by: \Car.id)
cars.uniq(by: \.id)