How to Get the Index in Results of a Certain Realm Object

Realm Swift Results get object at index

Use standard indexing syntax to retrieve the value:

let task = tasks![1]

Since tasks is an optional, it could be nil. A safer way to write this would be to use optional binding with optional chaining:

if let task = tasks?[1] {
    // use task
}

Realm-JS: Performant way to find the index of an element in sorted results list

Realm query methods return a Results object which is quite different from an Array object, the main difference is that the first one can change over time even without calling methods on it: adding and/or deleting record to the source schema can result in a change to Results object.

The only common thing between Results.indexOf and Array.indexOf is the name of the method.

Once said that is easy to also say that it makes no sense to compare the efficiency of the two methods.

In general, a problem common to all indexOf implementations is that they need a sequential scan and in the worst case (i.e. the not found case) a full scan is required. The wort implemented indexOf executed against 10 elements has no impact on program performances while the best implemented indexOf executed against 1M elements can have a severe impact on program performances. When possible it's always a good idea avoiding to use indexOf on large amounts of data.

Hope this helps.

How to retrieve data in Realm based on a given index range?

There is no need to implement pagination in realm queries, because they are "lazy" from the box.
It means objects are loaded from query only when you are accessing them.

SDK reference

Why can't I get the index of a filtered realm List?

I figured out the solution. The filter syntax I used .filter({ $0.title == "Child" }) isn't the Realm filter, and converts the List to a LazyFilterCollection<List<Model>>, which doesn't seem to be compatible with searching for the index of a realm object.

The fix was to use the format .filter("title == %@", "Child"), which returns a realm Results object.

How to access results from a realm in swift

You can retrieve specific SubscriptionClass by providing it's id which is used as primary key.

realm.object(ofType: SubscriptionClass.self, forPrimaryKey: id)

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