Modifying the value of structs inside an array of structs

Question

I have a struct like this

struct MyStruct {
  var name : String?
  var address : String?
  var affiliated : Bool?
}

and then an array of MyStruct

var myArray : [MyStruct]? ...

As soon as I create an array of MyStruct every element inside that array is non-mutating, right?

The problem is that at some point I have to scan that array and update a field of all elements, like updating affiliated for every element of myArray and this update is asynchronous.

This is my problem. All elements inside myArray are not mutating.

The way I would solve that was by recreating every MyStruct element with the new value for affiliated, recreating myArray and replacing the old array with this new one.

It seems a dumb method, a waste of time and effort.

Is there a better way to do this?

vadian · Accepted Answer · 2020-02-07 17:47:49Z

4

As soon as I create an array of MyStruct every element inside that array is non-mutating, right?

Not necessarily. But as arrays are value types you have to update an element of the array directly in the array for example

var myArray = [MyStruct(name: "Foo", address: nil, affiliated: false), MyStruct(name: "Bar", address: nil, affiliated: false)]

myArray[1].affiliated = true
print(myArray)

answered Feb 7, 2020 at 17:47

vadian

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1 Comment

Alexander Over a year ago

Yep. Subscripts are Swift's way to encode l-values (lots of info on this from the C++ world).

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