Count Annotations on MapView in Swift

Question

After completing a loop that places annotations on a map from an array, I want to count the number of annotations.

My code as follows:

let anCount = self.mapView.annotations?.count
            if (anCount > 1) {
//do something
            }

gives error:

Value of optional type 'Int?' must be unwrapped to a value of type 'Int'

The fixit suggestions yield other errors. What is the correct way to count the number of annotations for the map.

Thanks for any suggestions.

This has been asked and answered many times: https://stackoverflow.com/search?q=%22Value+of+optional+type%22+%22must+be+unwrapped%22 — Rob, Dec 31 '18 at 00:01
By the way, be careful of just counting at `annotations` because there might be different types of annotations. E.g., including or excluding the user location on the map (which results in a system generated [`MKUserLocation`](https://developer.apple.com/documentation/mapkit/mkuserlocation) to be added on your behalf) will suddenly change this logic. You really should filter the results for annotations of a particular type... — Rob, Dec 31 '18 at 00:14

Rob · Accepted Answer · 2018-12-31T00:12:59.530

1

You have to unwrap the optional, e.g. with if let, which you can then combine with the > 1 test in a single if statement:

if let anCount = mapView.annotations?.count, anCount > 1 {
    //do something
}

But annotations isn't an optional (at least in current iOS versions), so you'd probably just do:

let anCount = mapView.annotations.count
if anCount > 1 {
    //do something
}

edited Dec 31 '18 at 00:12

answered Dec 31 '18 at 00:00

Rob

Thanks for the answer which worked but did you downvote my question cause I took too long to respond? I had a lot going on. In theory, optionals should be simple, but in practice if you are still learning them, each case can be different. – user1904273 Dec 31 '18 at 15:38
No, I did not down vote. I was merely suggesting that you research more before posting a question. If you are going to post a question that has been asked before, it’s good to include references of a question or two to demonstrate that you did research it. – Rob Dec 31 '18 at 15:56

1 Answers1