Removing from set during enumeration in Swift?

Asked Feb 05 '17 at 17:38

Active Feb 05 '17 at 17:51

Viewed 53 times

Is it safe to delete an element from a set during enumeration?

for item in mySet {
    ...
    if needToRemove {
        mySet.remove(item)
    }
}

edited Feb 05 '17 at 17:51

Hamish

asked Feb 05 '17 at 17:38

Ilya

1

Just use filter – Leo Dabus Feb 05 '17 at 17:45
e.g. `set.filter { $0 % 2 == 0 }` – Rich Tolley Feb 05 '17 at 17:48
1

Yes, yes it is safe. `Set`, like many other collections in the standard library, is a value type – thus the set you're mutating and the set you're iterating over are independant from one another (see [this Q&A](http://stackoverflow.com/q/37997465/2976878)). – Hamish Feb 05 '17 at 17:48
@RichTolley it would return an array. He would need to create a set from it `mySet = Set(mySet.filter { condition } )` – Leo Dabus Feb 05 '17 at 17:49
oops, so it would – Rich Tolley Feb 05 '17 at 17:50
@MartinR Yup, agreed. I was just sidetracked by the fact that I no longer really like my answer there, which I'm currently editing :P – Hamish Feb 05 '17 at 18:34

0 Answers0