Realmswift: Convert Results to Swift Array

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 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 Swift - Convert an array of results into an array of Ints

You can simply use Array(realm.objects(RealmType.self)), which will convert the Results<RealmType> instance into an Array<RealmType>.

However, there are other serious flaws with your code. First of all, neither of the last two lines will compile, since firstly realm.objects() accepts a generic input argument of type Object.Type and Data doesn't inherit from Object. You can't directly store Data objects in Realm, you can only store Data as a property of a Realm Object subclass.

Secondly, myArray[results] is simply wrong, since results is supposed to be of type Results<RealmType>, which is a collection, so using it to index an Array cannot work (especially whose Element type is different).

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 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 Array of [[Double]] to String (similar to Print() output)

You can try

let intervals = [[1,1],[2,2],[3,3]] 
let res = "[\(intervals.map { "[\($0.first!),\($0.last!)]" }.joined(separator: ","))]" 
print(res)

OR

let res =  String(data: try! JSONEncoder().encode(intervals), encoding: .utf8)!

OR

let res = String(describing: intervals)

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