How to remove common items from two struct arrays in Swift

Question

In my app I have two struct arrays and I want to remove common items from one of them. My struct:

struct PeopleSelectItem {
    var name = \"\"
    var id =          


        

Answer 1

If people might have a significant amount of entries, performance should be considered. So, instead of searching with an n^2 algorithm, you should make use of Swifts dictionary and the corresponding hash-search to find items.

If Id is unique for people then I would store them in a dictionary like:

    var peopleDict: [String:PeopleSelectItem] = [:]()

You can easily convert from the array you have to this dictionary:

    people.foreach {peopleDict[$0.id] = $0}

With this dictionary it's very easy to delete single entries:

    selectedPeople.foreach {peopleDict.remove($0.id)}

Optionally to switch back to an array for people you just say:

    let filteredPeople = peopleDict.values as [PeopleSelectItem]

Remarks

1. I assumed, that selectedPeople is smaller then the base of all people. If this is not the case, you should pu selectedPeople in a dictionary.
2. did I say I like this Spark like api? I think I do so.
3. I just wrote that code from top of my mind. If it is not completely syntactically correct let me know and I correct it.