“Cannot assign to” error iterating through array of struct

Question

I have an array of structs:

struct CalendarDate {
    var date: NSDate?
    var selected = false
}

private var collectionData = [CalendarDate]()
         


        

Answer 1

As I understand it, the iterator

for c in collectionData

returns copies of the items in collectionData - (structs are value types, not reference types, see http://www.objc.io/issue-16/swift-classes-vs-structs.html), whereas the iteration

for i in 0..

accesses the actual values. If I am right in that, it is pointless to assign to the c returned from the iterator... it does not "point" at the original value, whereas the

collectionData[i].selected = false

in the iteration is the original value.

Some of the other commentators suggested

for (var c) in collectionData

but although this allows you to assign to c, it is still a copy, not a pointer to the original, and though you can modify c, collectionData remains untouched.

The answer is either A) use the iteration as you originally noted or B) change the data type to a class, rather than a struct.