Covert Realm List to Realm Result

How to convert RealmResults object to RealmList?

RealmList <Student> results = new RealmList<Student>();

results.addAll(realmResultList.subList(0, realmResultList.size()));

RealmSwift: Convert Results to Swift Array

I found a solution. Created extension on Results.

extension Results {
    func toArray<T>(ofType: T.Type) -> [T] {
        var array = [T]()
        for i in 0 ..< count {
            if let result = self[i] as? T {
                array.append(result)
            }
        }

        return array
    }
}

and using like

class func getSomeObject() -> [SomeObject]? {
    let objects = Realm().objects(SomeObject).toArray(SomeObject) as [SomeObject]

    return objects.count > 0 ? objects : nil
}

how to convert RealmListT to RealmResultsT

Simple use query on your list :

class MyObject extends RealmObject {

    RealmList<MySubObject> subObjects;
}

...

myObject.subObjects.where().findAll(); //returns a RealmResults

//you can query your list like
myObject.subObjects
     .where()
     .equalTo("status", "done")
     .findAll(); //you can use sort, findFirst etc

how to convert RealmSwift List to Results?

Both List and Results (as well as LinkingObjects) can be converted into an AnyRealmCollection type. I think this is probably the best way to standardize all of Realm's array-type types:

var dataSource:AnyRealmCollection!
let aRealmObject = realm.objectForPrimaryKey(SomeObject.self, key: objectId) 
dataSource = AnyRealmCollection(aRealmObject.someList)

Convert Swift Array of Realm Objects Back to Realm Results

Do this:

let entryObjects = realm.objects(Entry.self).filter(...)
let total = entryObjects.map({ $0.fieldValues.sum(ofProperty: "total") }).reduce(0, +)

When Realm support aggregate operations on nested keypaths (#3392) it'll be possible to use KVC for this, but that's still in progress.

How to convert an array to List in Realm?

Note that your problem is not about converting List to array, but rather converting an array to List. You already know how to do the former: Array(someList), but since you are assigning an array (movie.genreIDs ?? []) to a List property (movieRealm.genreIDs), you need to convert an array to a List.

But wait! movieRealm.genreIDs is a let constant, so you can't assign to it anyway. Your real problem is that you haven't declared the genreIDs property correctly.

If you follow the docs on how to declare a property of a List type:

class CachedMovies: Object {
     // genreIDs should not be optional
     let genreIDs = List<Int>()
}

You'll see that you don't need to convert arrays to List. You can just add the contents of the array to the List, since the list is not nil:

movieRealm.genreIDs.append(objectsIn: move.genreIDs ?? [])

Note that if you actually want an optional list property (a property which can be nil, empty, or have elements), Realm doesn't support that.

Realm: ResultsT als ListT

We can use extensions to make life easier :

extension Realm {
    func list<T: Object>(_ type: T.Type) -> List<T> {
        let objects = self.objects(type)
        let list = objects.reduce(List<T>()) { list, element -> List<T> in
            list.append(element)
            return list
        }
        
        return list
    }
}

Usage:

let objects = realm.list(YourObject.self)

How to convert RealmResultsObject to ListObject

To eagerly read every element from the Realm (and therefore make all elements in the list become unmanaged, you can do):

 List<StepEntry> arrayListOfUnmanagedObjects = realm.copyFromRealm(realmResults);

But you generally have absolutely no reason to do that unless you want to serialize the objects with GSON (specifically, because it reads field data with reflection rather than with getters), because Realm was designed in such a way that the list exposes a change listener, allowing you to keep your UI up to date just by observing changes made to the database.

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