How to remove duplicate objects from array on swift?

Question

I have for example this array:

[
 {
 "name": "Daniel",
 "points": 10,
 },
 {
 "name": "Ana",
 "points": 20
 },
 {
 "name": "Daniel",
 "points": 40
 }
 ]

And i want delete one "Daniel" and points to the sum of all whit the same name like this:

[
 {
 "name": "Daniel",
 "points": 50,
 },
 {
 "name": "Ana",
 "points": 20
 }
 ]

How can i transform it?

I was trying whit two bucles:

 for name in persons {
 for name2 in persons {
 if name == name2 {
 //remove the duplicate one and sum his points
 }
 }
 
 }
 

but maybe there is a way too much easier than this one

• Larme: Are you manipulating only Swift Dictionaries, or do you have a model/custom struct? Is the finial order important? If yes, what's the logic?

Answer 1

A possible solution is to group the array with Dictionary(grouping:by:) then mapValues to the sum of the points.

The resulting dictionary [<name>:<points>] can be remapped to Person instances

struct Person {
 let name: String
 let points: Int
}
let people = [
 Person(name: "Daniel", points: 10),
 Person(name: "Ana", points: 20),
 Person(name: "Daniel", points: 40),
]
let result = Dictionary(grouping: people, by: \.name)
 .mapValues{ 0ドル.reduce(0, {0ドル + 1ドル.points})} // ["Daniel":50, "Ana":20]
 .map(Person.init)
print(result) // [Person(name: "Daniel", points: 50), Person(name: "Ana", points: 20)]