RealmKeyedCollection

The type of key associated with this collection

The type of value associated with this collection.

The Realm which manages the map, or nil if the map is unmanaged.

Indicates if the map can no longer be accessed.

Returns the number of key-value pairs in this map.

A human-readable description of the objects contained in the Map.

Updates the value stored in the dictionary for the given key, or adds a new key-value pair if the key does not exist.

Removes the given key and its associated object, only if the key exists in the dictionary. If the key does not exist, the dictionary will not be modified.

Removes all objects from the dictionary. The objects are not removed from the Realm that manages them.

Returns the value for a given key, or sets a value for a key should the subscript be used for an assign.

Returns a type of Value for a specified key if it exists in the map.

Note that when using key-value coding, the key must be a string.

Returns a type of Value for a specified key if it exists in the map.

Adds a given key-value pair to the dictionary or updates a given key should it already exist.

Returns a Results containing all matching values in the dictionary with the given predicate.

Returns a Boolean value indicating whether the Map contains the key-value pair satisfies the given predicate

Returns a Results containing the objects in the dictionary, but sorted.

Objects are sorted based on their values. For example, to sort a dictionary of Dates from neweset to oldest based, you might call dates.sorted(ascending: true).

Returns a Results containing the objects in the dictionary, but sorted.

Objects are sorted based on the values of the given key path. For example, to sort a dictionary of Students from youngest to oldest based on their age property, you might call students.sorted(byKeyPath: "age", ascending: true).

Returns a Results containing the objects in the dictionary, but sorted.

Returns all of the keys in this dictionary.

Returns all of the values in the dictionary.

Returns the minimum (lowest) value of the given property among all the objects in the collection, or nil if the dictionary is empty.

Returns the maximum (highest) value of the given property among all the objects in the dictionary, or nil if the dictionary is empty.

Returns the sum of the given property for objects in the dictionary, or nil if the dictionary is empty.

Returns the average value of a given property over all the objects in the dictionary, or nil if the dictionary is empty.

Registers a block to be called each time the dictionary changes.

The block will be asynchronously called with the initial dictionary, and then called again after each write transaction which changes either any of the keys or values in the dictionary.

The change parameter that is passed to the block reports, in the form of keys within the dictionary, which of the key-value pairs were added, removed, or modified during each write transaction.

At the time when the block is called, the dictionary will be fully evaluated and up-to-date, and as long as you do not perform a write transaction on the same thread or explicitly call realm.refresh(), accessing it will never perform blocking work.

If no queue is given, notifications are delivered via the standard run loop, and so can’t be delivered while the run loop is blocked by other activity. If a queue is given, notifications are delivered to that queue instead. When notifications can’t be delivered instantly, multiple notifications may be coalesced into a single notification. This can include the notification with the initial collection.

For example, the following code performs a write transaction immediately after adding the notification block, so there is no opportunity for the initial notification to be delivered first. As a result, the initial notification will reflect the state of the Realm after the write transaction.

let myStringMap = myObject.stringMap
print("myStringMap.count: \(myStringMap?.count)") // => 0
let token = myStringMap.observe { changes in
    switch changes {
    case .initial(let myStringMap):
        // Will print "myStringMap.count: 1"
        print("myStringMap.count: \(myStringMap.count)")
       print("Dog Name: \(myStringMap["nameOfDog"])") // => "Rex"
        break
    case .update:
        // Will not be hit in this example
        break
    case .error:
        break
    }
}
try! realm.write {
    myStringMap["nameOfDog"] = "Rex"
}
// end of run loop execution context

If no key paths are given, the block will be executed on any insertion, modification, or deletion for all object properties and the properties of any nested, linked objects. If a key path or key paths are provided, then the block will be called for changes which occur only on the provided key paths. For example, if:

class Dog: Object {
    @Persisted var name: String
    @Persisted var age: Int
    @Persisted var toys: List<Toy>
}
// ...
let dogs = myObject.mapOfDogs
let token = dogs.observe(keyPaths: ["name"]) { changes in
    switch changes {
    case .initial(let dogs):
       // ...
    case .update:
       // This case is hit:
       // - after the token is initialized
       // - when the name property of an object in the
       // collection is modified
       // - when an element is inserted or removed
       //   from the collection.
       // This block is not triggered:
       // - when a value other than name is modified on
       //   one of the elements.
    case .error:
        // ...
    }
}
// end of run loop execution context

• If the observed key path were ["toys.brand"], then any insertion or deletion to the toys list on any of the collection’s elements would trigger the block. Changes to the brand value on any Toy that is linked to a Dog in this collection will trigger the block. Changes to a value other than brand on any Toy that is linked to a Dog in this collection would not trigger the block. Any insertion or removal to the Dog type collection being observed would also trigger a notification.

• If the above example observed the ["toys"] key path, then any insertion, deletion, or modification to the toys list for any element in the collection would trigger the block. Changes to any value on any Toy that is linked to a Dog in this collection would not trigger the block. Any insertion or removal to the Dog type collection being observed would still trigger a notification.

You must retain the returned token for as long as you want updates to be sent to the block. To stop receiving updates, call invalidate() on the token.

Returns if this collection is frozen

Returns a frozen (immutable) snapshot of this collection.

The frozen copy is an immutable collection which contains the same data as this collection currently contains, but will not update when writes are made to the containing Realm. Unlike live collections, frozen collections can be accessed from any thread.

Returns a live (mutable) version of this frozen collection.

This method resolves a reference to a live copy of the same frozen collection. If called on a live collection, will return itself.

A publisher that emits Void each time the collection changes.

Despite the name, this actually emits after the collection has changed.

A publisher that emits the collection each time the collection changes.

A publisher that emits the collection each time the collection changes on the given property keyPaths.

A publisher that emits a collection changeset each time the collection changes.

A publisher that emits a collection changeset each time the collection changes on the given property keyPaths.

Returns the minimum (lowest) value of the given property among all the objects in the collection, or nil if the collection is empty.

Returns the maximum (highest) value of the given property among all the objects in the collection, or nil if the collection is empty.

Returns the sum of the given property for objects in the collection, or nil if the collection is empty.

Returns the average value of a given property over all the objects in the collection, or nil if the collection is empty.

Returns a Results containing the objects in the collection, but sorted.

Objects are sorted based on the values of the given key path. For example, to sort a collection of Students from youngest to oldest based on their age property, you might call students.sorted(byKeyPath: "age", ascending: true).

Returns the minimum (lowest) value of the collection, or nil if the collection is empty.

Returns the maximum (highest) value of the collection, or nil if the collection is empty.

Returns the sum of the values in the collection, or nil if the collection is empty.

Returns the average of all of the values in the collection.