Filtering duplicates in array and deleting array elements from another array in swift 2.0

Question

I'm trying to delete duplicate elements of type [(Int,Int)] from an array, then I'm trying to delete an array of elements of same type from parent array. This is how I do it.

func filterDuplicatesFrom(var buttonArray:[(Int,Int)]) ->[(Int,Int)]
 {
 var i: Int = 0, j:Int = 0
 var elementToDelete:[Int] = []
 for (i=0; i<buttonArray.count-1; i++)
 {
 for (j=i+1; j<buttonArray.count; j++)
 {
 if buttonArray[j].0 == buttonArray[i].0 && buttonArray[j].1 == buttonArray[i].1
 {
 if elementToDelete.contains(j)
 {
 elementToDelete.append(j)
 }
 }
 }
 }
 buttonArray.removeAtIndices(elementToDelete)
 }
func deletePoints(var deleteList:[(Int,Int)],var buttonArray:[(Int,Int)]) ->[(Int,Int)]
{
 var i: Int = 0, j:Int = 0
 var elementToDelete:[Int] = []
 for (i=0; i<buttonArray.count; i++)
 {
 for (j=0; j<deleteList.count; j++)
 {
 if deleteList[j].0 == buttonArray[i].0 && deleteList[j].1 == buttonArray[i].1
 {
 if elementToDelete.contains(i)
 {
 elementToDelete.append(i)
 }
 }
 }
 }
 buttonArray.removeAtIndices(elementToDelete)
}
extension Array {
 mutating func removeAtIndices(incs: [Int]) {
 incs.sort(>).map { removeAtIndex(0ドル) }
 }

This seems to work, but I wonder if it would effect the performance for large number of data. Is there a better way to do this? or what I've done is correct?

Answer 1

You could replace the tuple with a struct that conforms to Hashable protocol.

struct Button: Hashable {
 ...
}

Then if you have an array of instances of this struct you can use Sets to filter duplicates and subtract one set from the other. Sets are a collection of unordered unique elements.

/// remove duplicates (create a set)
func filterDuplicatesFrom(buttonArray:[Button]) -> Set<Button> {
 return Set(buttonArray)
}
/// delete
func deletePoints(deleteList:[Button], buttonArray:[Button]) -> Set<Button> {
 return Set(buttonArray).subtract(Set(deleteList))
}