append a NSSet with array values

Question

How can i append my HKObjectTypes into a NSSet.
It always returns empty. Any better way???

     func getPermsFromOptions(_ options: NSArray) -> NSSet {
            var readPermSet = NSSet()
            var optionKey: String
            var val: HKObjectType
                
           for i in options{
            optionKey = i as! String
            val = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier(rawValue: optionKey))!

             readPermSet.adding(val)    
             print("set", readPermSet)           //always empty

                      }
                  return readPermSet;
              }

var readPermSet = NSSet() => var readPermSet = NSMutabmeSet() and then, readPermSet.add(val), but why do you keep using NSArray and NSSet? Can't you use Swift Set and Array instead? — Larme
– Larme, Commented Apr 9, 2021 at 8:42

Shadowrun · Accepted Answer · 2021-04-09 08:39:50Z

1

readPermSet.adding(val)

Adding isn't a mutating method, it returns a new set that has the other value added

Try it with:

var readPermSet: Set<HKObjectType> = []

and

readPermSet.insert(val)

answered Apr 9, 2021 at 8:39

Shadowrun

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Comments

Sweeper · Accepted Answer · 2021-04-09 08:45:00Z

1

You cannot add to an NSSet. You can add to an NSMutableSet:

var readPermSet = NSMutableSet()
...
readPermSet.add(val)

adding is a method from Swift, that returns a new set with all the same elements, plus the new element. You are ignoring its return value here.

Since you are in Swift, why not use Set<HKObjectType> and [String]?

func getPermsFromOptions(_ options: [String]) -> Set<HKObjectType> {
    var readPermSet = Set<HKObjectType>()
    for optionKey in options {
        let val = HKObjectType.quantityType(forIdentifier: HKQuantityTypeIdentifier(rawValue: optionKey))!
         readPermSet.insert(val)    
         print("set", readPermSet)
     }
     return readPermSet;
 }

answered Apr 9, 2021 at 8:45

Sweeper

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