How to mutate Values inside a Array

Question

I need to mutate the following array:

struct Person {
    var name: String
    var age = 0
    }

func showPersonArray() -> [Person] {

    var dataArray = [Person]()

    dataArray.append(Person(name: "Sarah_Yayvo", age: 29))
    dataArray.append(Person(name: "Shanda_Lear", age: 45))
    dataArray.append(Person(name: "Heidi_Clare", age: 45))

    return dataArray
}

How could I split the "name"-key into two keys: "givenName" and "familyName". Some nice person gave me this code before:

let arraySeparated1 = dataArray.map { $0.substring(to: $0.range(of: "_")!.lowerBound) }
let arraySeparated2 = dataArray.map { $0.substring(from: $0.range(of: "_")!.upperBound) }

Is it possible to make the mutation inside the struct? The function showPersonArray() is only for demo and test. Maybe there is a way to work with a target struct, like this:

struct Persontarget {
    var familyname: String
    var givenName: String
    var age = 0
}

struct Person: Array -> [Persontarget]  {
    var name: String
    var age = 0

    // Here the split/mutating code

    return [PersonWithTwoNames]
}

Or with an String extension. Possibly my question sounds pretty newby-like, but i´m trying the whole day... Thanks everyone!

Answer 1

I would write an initializer on the new Person type, which initializes it from the old person type (which I called LegacyPerson):

import Foundation

struct LegacyPerson {
    let name: String
    let age: Int
}

func getPersonArray() -> [LegacyPerson] {
    return [
        LegacyPerson(name: "Sarah_Yayvo", age: 29),
        LegacyPerson(name: "Shanda_Lear", age: 45),
        LegacyPerson(name: "Heidi_Clare", age: 45)
    ]
}

struct Person {
    let familyName: String
    let givenName: String
    let age: Int
}

extension Person {
    init(fromLegacyPerson person: LegacyPerson) {
        let index = person.name.range(of: "_")!
        self.init(
            familyName: person.name.substring(from: index.upperBound),
            givenName: person.name.substring(to: index.lowerBound),
            age: person.age
        )
    }
}

let people: [Person] = getPersonArray().map(Person.init)

people.forEach{ print($0) }