Unique array of objects

Question

I have an array that looks like this:

var persons = [Person]()

And a person contains this:

id : Int
name : String
age : Int
gender : String

In my persons list I have multiple persons, but how do I sort this list on unique names?

I found this let unique = Array(Set(originals)) but it does not seem to work on a list of objects, I want to keep all the information of the object.

If my list contains these rows:

Adam, Adam, John, John, Michael, Nick, Tony

I only want to show:

Adam, John, Michael, Nick Tony

And I still want to be able to get Adams age for example.

Any ideas?

Edit
Person declaration

import Foundation

public class Person : NSObject {
    var id = ""
    var name = ""
    var age = 0
    var gender = ""
}

func ==(lhs: Person, rhs: Person) -> Bool {
    return lhs.name == rhs.name
}

You need to make your class Person Equatable and then you can use this extension stackoverflow.com/questions/25738817/… — Leo Dabus
– Leo Dabus, Commented Sep 5, 2016 at 4:24
@LeoDabus, I have done that now but I´m not sure how to filter the list now. — user5855868
– user5855868, Commented Sep 5, 2016 at 4:30
func ==(lhs: Person, rhs: Person) -> Bool { return lhs.id == rhs.id } — Leo Dabus
– Leo Dabus, Commented Sep 5, 2016 at 4:30
What does sorting on unique names mean? Does it mean taking out duplicate records and then sorting on name field? — Ozgur Vatansever
– Ozgur Vatansever, Commented Sep 5, 2016 at 4:37

Leo Dabus · Accepted Answer · 2018-09-17 23:29:54Z

2

You need to add this extension to return an ordered set from your people array.

extension Collection where Element: Hashable {
    var orderedSet: [Element] {
        var set: Set<Element> = []
        return reduce(into: []){ set.insert($1).inserted ? $0.append($1) : ()  }
    }
}

You will also have to make your Person class Equatable:

func ==(lhs: Person, rhs: Person) -> Bool {
    return lhs.id == rhs.id
} 

class Person: Equatable { 
    let id: String 
    let name: String 
    init(id: String, name: String) { 
        self.id = id 
        self.name = name 
    } 
}

Testing

let person1 = Person(id: "1", name: "Adam") 
let person2 = Person(id: "1", name: "Adam") 
let person3 = Person(id: "2", name: "John") 
let person4 = Person(id: "2", name: "John") 
let person5 = Person(id: "3", name: "Michael") 
let person6 = Person(id: "4", name: "Nick") 
let person7 = Person(id: "5", name: "Tony") 
let people = [person1,person2,person3,person4,person5,person6,person7] 
people.orderedSet //[{id "1", name "Adam"}, {id "2", name "John"}, {id "3", name "Michael"}, {id "4", name "Nick"}, {id "5", name "Tony"}]

edited Sep 17, 2018 at 23:29

answered Sep 5, 2016 at 5:23

Leo Dabus

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2 Comments

user5855868 Over a year ago

He has added you on Skype now Leo, have you seen it?

Leo Dabus Over a year ago

I will check it

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