struct Person {
var name: String
var age: Int
var weight : Int
var shoeSize: Int
}
struct Group {
var members : [Person]
}
let mygroup = Group(members: [
Person(name: "Billy", age: 59, weight: 170, shoeSize: 9),
Person(name: "Jacob", age: 19, weight: 130, shoeSize: 11),
Person(name: "Zara", age: 25, weight: 320, shoeSize: 10)
])
How can I multiple each age by 2, and return a new array (myGroupV2), but leave the other elements untouched?
You simply need to use map to apply a closure to each element of an Array. In your map closure, you need to initialise a new Person instance, where all inputs are the same as the properties of the original Person, except for age, which you multiply by 2.
let myGroup2 = Group(members: mygroup.members.map { Person(name: $0.name, age: $0.age * 2, weight: $0.weight, shoeSize: $0.shoeSize) })
Instead of individually assigning all the properties of Person, you can simply create a new Person instance and change its age property, i.e.
let myGroupV2 = mygroup.members.map {(person) -> Person in
var person = person
person.age *= 2
return person
}
In case you need it more than once, an extention can also be helpful:
extension Person {
var asDoubleAged: Person {
get {
return Person(name: self.name, age: self.age * 2, weight: self.weight, shoeSize: self.shoeSize)
}
}
}
let myGroupV2 = Group(members: mygroup.members.map { $0.asDoubleAged })
let personArray = mygroup.members.map { p in Person(name: p.name, age: p.age*2, weight: p.weight, shoeSize: p.shoeSize) }
let mygroup2=Group(members: personArray)
let mygroup2 = Group(members: mygroup.members.map { Person(name: $0.name, age: $0.age*2, weight: $0.weight, shoeSize: $0.shoeSize)})
