Filter in Realm List Swift

Filter in realm list swift

This was a very challenging query but I think I have a solution.

First however; Primitives in Realm Lists are not well supported and are not yet queryable. See here and this for more reading.

EDIT: Release 10.7 added support for filters/queries as well as aggregate functions on primitives so the below info is no longer completely valid. However, it's still something to be aware of.

So we will need to add another class to hold the string data

class StringClass: Object {
    @objc dynamic var myString = ""
}

so the following class will be updated to match

class ParamsModel: BaseResponse {
    var options = List<StringClass>()
}

Then to peform the query we need to leverage a Subquery due to the depth of the objects.

let predicate = NSPredicate(format: "SUBQUERY(customFields, $customField, ANY $customField.params.options.myString == 'custom').@count > 0")
let results = realm.objects(RetailerModel.self).filter(predicate)

This will return all Retailer Models whose CustomFieldsModel has a ParamsModel options List property StringClass myString property equal to 'custom'

Realm List Filter Swift

This error occurs if you try and perform a query on a Realm Swift List object (Which are actually Objective-C RLMArray objects under the hood) before its parent object has been added to a Realm.

class Person: Object {
  dynamic var name = ""
  dynamic var picture: NSData? = nil // optionals supported
  let dogs = List<Dog>()
}

let dog = Dog()
dog.name = "Rex"

let person = Person()
person.dogs.append(dog)

let rex = person.dogs.filter("name == 'Rex'") // QUERY WILL TRIGGER EXCEPTION AT THIS POINT

let realm = try! Realm()
try! realm.write {
    realm.add(person)
}

let rex = person.dogs.filter("name == 'Rex'") // Query will now work as expected

In a nutshell, you need to make sure that numbersDetail belongs to a Realm before you perform that query. You can easily test this by checking numbersDetail.realm != nil.

iOS Realm Filter objects in a list of a relationship

Realm doesn't have any sort of concept of a deep-filtered view, so you can't have a Results<Canteen> which restricts the Lists contained in related objects to vegan meals.

There are several similar things which you can do. You could add inverse relationship properties, and then query Meal objects instead:

class Canteen: Object {
    dynamic var name: String?
    let lines = List<Line>()
}

class Line: Object {
    dynamic var name: String?
    let meals = List<Meal>()
    let canteens = LinkingObjects(fromType: Canteen.self, property: "lines")
}

class Meal: Object {
    dynamic var name: String?
    dynamic var vegan: Bool = false
    let lines = LinkingObjects(fromType: Line.self, property: "meals")
}

let meals = realm.objects(Meal).filter("vegan = true AND ANY lines.canteens.name = %@", selectedCanteenType.rawValue)

(Or rather, you will be able to once Realm 0.102.1 is out; currently this crashes).

If you just need to iterate over the meals but need to do so from the Canteen down, you could do:

let canteens = realm.objects(Canteen).filter("name = %@ AND ANY lines.meals.vegan = true", selectedCanteenType.rawValue)
for canteen in canteens {
    for line in canteen.lines.filter("ANY meals.vegan = true") {
        for meal in line.meals.filter("vegan = true") {
            // do something with your vegan meal
        }
    }
}

This unfortunately has some duplication due to needing to repeat the filter for each level of the references.

How to filter Realm objects by list

try this solution

If you use a to-many relationship, You use an ANY operator

Please read this well so you understand what to use because there is another operator ex ALL,ANY,NONE Predicate Programming Guide

 private func getDeviceContacts(_ phoneNumbers: [Int64]) -> [DeviceContactModel] {
            do {
                let realm = try Realm()
                let deviceContacts = Array(realm.objects(DeviceContactModel.self).filter("ANY phones.fullNumber IN %@", phoneNumbers))
                return deviceContacts
            } catch {
                debugPrint(error.localizedDescription)
                return []
            }
        }

Realm Swift Filter Query Based On List Property

Let me restate the question;

You want an artist to be able to query for all new shows in cities
they are interested in where they have not yet responded.

If that's the question, let me start with some simple sample data

Two artists that have each have two cities if interest

let a0 = Artist()
a0.name = "Jim"
a0.citiesOfInterest.append(objectsIn: ["Austin", "Memphis"])

let a1 = Artist()
a1.name = "Henry"
a1.citiesOfInterest.append(objectsIn: ["Austin", "Memphis"])

and then two shows, one in each city

let s0 = Show()
s0.name = "Austin Show"
s0.city = "Austin"

let s1 = Show()
s1.name = "Memphis Show"
s1.city = "Memphis"

but artist a0 (Jim) has responded to the s0 (Austin) show

let r0 = ArtistResponse()
r0.show = s0
r0.artist = a0
r0.available = true

s0.artistResponses.append(r0) //jim responded to the Austin show

The result we want is that when Jim the artist logs on, he will see the Memphis show because he already responded to the Austin show.

let realm = try! Realm()
if let jim = realm.objects(Artist.self).filter("name == 'Jim'").first {
   let myCities = jim.citiesOfInterest
   let showResults = realm.objects(Show.self)
                          .filter("city IN %@ AND !(ANY artistResponses.artist.name == 'Jim')", myCities)
   for show in showResults {
      print(show.name)
   }              
}

And the output is

Memphis Show

We first get the Jim's cities of interest as an array, then we filter the shows that match those cities of interest but where there are no artist responses associated with Jim. This filter was based on the name but you could use the Artist id or even the Artist object itself as the comparator.

How can I filter a Realm List by Date Swift NSPredicates

You would need to use a date range filter. You would need to start the range at a specific date and end it at a certain date. For example,

let predicate = NSPredicate(format: "artSoldDate >= %@ AND artSoldDate <= %@", startDate, endDate)

let result = realm.objects(Art.self).filter(predicate)

Your example seems to try and check when the artSoldDate is exactly some date.

Filter querying multiple objects from Realm using List of Primary Keys

I think you are asking how to query Realm for items that have keys that match a set of keys in an array.

So given a DogClass Realm Object

class DogClass: Object {
    @objc dynamic var dog_id = NSUUID().uuidString
    @objc dynamic var dog_name = ""

    override static func primaryKey() -> String? {
        return "dog_id"
    }
}

and suppose we know we want to retrieve three dogs that match some given primary keys

let keysToMatch = ["302AC133-3980-41F3-95E8-D3E7F639B769", "54ECC485-4910-44E5-98B9-0712BB99783E", "71FE403B-30CD-4E6C-B88A-D6FDBB08C509"]
let dogResults = realm.objects(DogClass.self).filter("dog_id IN %@", keysToMatch)
for dog in dogResults {
    print(dog.dog_id, dog.dog_name)
}

Note the use of IN in the filter, which will match any dogs with id's in the given array.

You can also pass in a Realm List Object instead of a Swift array and get the same result.

let listOfKeysToMatch = List<String>()
listOfKeysToMatch.append("302AC133-3980-41F3-95E8-D3E7F639B769")
listOfKeysToMatch.append("54ECC485-4910-44E5-98B9-0712BB99783E")
listOfKeysToMatch.append("71FE403B-30CD-4E6C-B88A-D6FDBB08C509")
let dogResults2 = realm.objects(DogClass.self).filter("dog_id in %@", listOfKeysToMatch)
for dog in dogResults2 {
    print(dog.dog_id, dog.dog_name)
}

How to access the realm model list in filter in swift 4?

Realm support .filter() function based on NSPredicate. So, first you should get ibp_service_filter == true values:

let filteredServices = chapter.service.filter("ibp_service_filter == true")

and then save only uniq ids (basic idea):

for service in filteredServices where !history_ibp.contains(where: { $0. service_id == service.service_id }) {
    history_ibp.append(service)
}

Swift Realm filter List property using an Array

You can't achieve your goals using predicate with Realm because Realm have a lot of limitations using Predicates and the missing ability to handle computed properties but you can use this way as a workarround

    let filterList = ["A","B"]
    let realmList = realmInstance?.objects(MyDTO.self)
    let filteredArray = Array(realmList!).filter({Array($0.tags).map({$0.tagName}).sorted().joined().contains(filterList.sorted().joined())})

here Array($0.tags).map({$0.tagName}).sorted().joined() we get the tags array and convert it with map to an array of Strings then we sort that array of Strings (this will ensure that only matters the TAGS in the array not the order) and after that we convert that sorted array in a String by example your array of tags.tagName is ["B","A","C"] and after this you will get "ABC" as STRING

after that we check if that STRING contains your filterList.sorted().joined() the same procedure that was explained before

so if your filterList have ["B","C","A"] you will get "ABC"

and the we check if "ABC" contains "ABC" if so then is included in final result

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