Results

public final class Results<T: Object>: ResultsBase

Results is an auto-updating container type in Realm returned from object queries.

Results can be queried with the same predicates as List<T>, and you can chain queries to further filter query results.

Results always reflect the current state of the Realm on the current thread, including during write transactions on the current thread. The one exception to this is when using for...in enumeration, which will always enumerate over the objects which matched the query when the enumeration is begun, even if some of them are deleted or modified to be excluded by the filter during the enumeration.

Results are lazily evaluated the first time they are accessed; they only run queries when the result of the query is requested. This means that chaining several temporary Results to sort and filter your data does not perform any extra work processing the intermediate state.

Once the results have been evaluated or a notification block has been added, the results are eagerly kept up-to-date, with the work done to keep them up-to-date done on a background thread whenever possible.

Results cannot be directly instantiated.

Properties

  • Returns the object at the given index.

    Declaration

    Swift

    public subscript(index: Int) -> T

    Parameters

    index

    An index.

    Return Value

    The object at the given index.

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  • The type of the objects contained in the collection.

    Declaration

    Swift

    public typealias Element = T
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  • The Realm which manages this results collection. Note that this property will never return nil.

    Declaration

    Swift

    public var realm: Realm? { return Realm(rlmResults.realm) }
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  • Indicates if the results collection is no longer valid.

    The results collection becomes invalid if invalidate is called on the containing realm. An invalidated results collection can be accessed, but will always be empty.

    Declaration

    Swift

    public var invalidated: Bool { return rlmResults.invalidated }
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  • The number of objects in the results collection.

    Declaration

    Swift

    public var count: Int { return Int(rlmResults.count) }
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Index Retrieval

  • Returns the index of an object in the results collection.

    Declaration

    Swift

    public func indexOf(object: T) -> Int?

    Parameters

    object

    An object.

    Return Value

    The index of the given object, or nil if the object is not in the results collection.

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  • Returns the index of the first object matching the predicate.

    Declaration

    Swift

    public func indexOf(predicate: NSPredicate) -> Int?

    Parameters

    predicate

    The predicate with which to filter the objects.

    Return Value

    The index of the first object that matches, or nil if no objects match.

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  • Returns the index of the first object matching the predicate.

    Declaration

    Swift

    public func indexOf(predicateFormat: String, _ args: AnyObject...) -> Int?

    Parameters

    predicateFormat

    A predicate format string, optionally followed by a variable number of arguments.

    Return Value

    The index of the first object that matches, or nil if no objects match.

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Object Retrieval

  • Returns the first object in the results collection, or nil if the collection is empty.

    Declaration

    Swift

    public var first: T? { return unsafeBitCast(rlmResults.firstObject(), Optional<T>.self) }
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  • Returns the last object in the results collection, or nil if the collection is empty.

    Declaration

    Swift

    public var last: T? { return unsafeBitCast(rlmResults.lastObject(), Optional<T>.self) }
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KVC

  • Returns an Array containing the results of invoking valueForKey(_:) with key on each of the results collection’s objects.

    Declaration

    Swift

    public override func valueForKey(key: String) -> AnyObject?

    Parameters

    key

    The name of the property.

    Return Value

    An Array containing the results.

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  • Returns an Array containing the results of invoking valueForKeyPath(_:) with keyPath on each of the results collection’s objects.

    Declaration

    Swift

    public override func valueForKeyPath(keyPath: String) -> AnyObject?

    Parameters

    keyPath

    The key path to the property.

    Return Value

    An Array containing the results.

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  • Invokes setValue(_:forKey:) on each of the results collection’s objects using the specified value and key.

    Warning

    This method may only be called during a write transaction.

    Declaration

    Swift

    public override func setValue(value: AnyObject?, forKey key: String)

    Parameters

    value

    The object value.
    key

    The name of the property.
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Filtering

  • Returns all objects matching the given predicate in the collection.

    Declaration

    Swift

    public func filter(predicateFormat: String, _ args: AnyObject...) -> Results<T>

    Parameters

    predicateFormat

    A predicate format string, optionally followed by a variable number of arguments.

    Return Value

    A Results containing objects that match the given predicate.

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  • Returns all objects matching the given predicate in the collection.

    Declaration

    Swift

    public func filter(predicate: NSPredicate) -> Results<T>

    Parameters

    predicate

    The predicate with which to filter the objects.

    Return Value

    A Results containing objects that match the given predicate.

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Sorting

  • Returns a sorted Results from the collection.

    Declaration

    Swift

    public func sorted(property: String, ascending: Bool = true) -> Results<T>

    Parameters

    property

    The property name to sort by.
    ascending

    The direction to sort in.

    Return Value

    A Results sorted by the specified property.

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  • Returns a sorted Results from the collection.

    Declaration

    Swift

    public func sorted<S: SequenceType where S.Generator.Element == SortDescriptor>(sortDescriptors: S) -> Results<T>

    Parameters

    sortDescriptors

    A sequence of SortDescriptors to sort by.

    Return Value

    A Results sorted by the specified properties.

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Aggregate Operations

  • Returns the minimum (lowest) value of the given property among all the objects represented by the collection.

    Warning

    Only a property whose type conforms to the MinMaxType protocol can be specified.

    Declaration

    Swift

    public func min<U: MinMaxType>(property: String) -> U?

    Parameters

    property

    The name of a property whose minimum value is desired.

    Return Value

    The minimum value of the property, or nil if the collection is empty.

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  • Returns the maximum (highest) value of the given property among all the objects represented by the collection.

    Warning

    Only a property whose type conforms to the MinMaxType protocol can be specified.

    Declaration

    Swift

    public func max<U: MinMaxType>(property: String) -> U?

    Parameters

    property

    The name of a property whose minimum value is desired.

    Return Value

    The maximum value of the property, or nil if the collection is empty.

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  • Returns the sum of the values of a given property over all the objects represented by the collection.

    Warning

    Only a property whose type conforms to the AddableType protocol can be specified.

    Declaration

    Swift

    public func sum<U: AddableType>(property: String) -> U

    Parameters

    property

    The name of a property whose values should be summed.

    Return Value

    The sum of the given property.

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  • Returns the average value of a given property over all the objects represented by the collection.

    Warning

    Only the name of a property whose type conforms to the AddableType protocol can be specified.

    Declaration

    Swift

    public func average<U: AddableType>(property: String) -> U?

    Parameters

    property

    The name of a property whose average value should be calculated.

    Return Value

    The average value of the given property, or nil if the collection is empty.

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Notifications

  • Registers a block to be called each time the results collection changes.

    The block will be asynchronously called with the initial results, and then called again after each write transaction which changes either any of the objects in the collection, or which objects are in the collection.

    The change parameter that is passed to the block reports, in the form of indices within the collection, which of the objects were added, removed, or modified during each write transaction. See the RealmCollectionChange documentation for more information on the change information supplied and an example of how to use it to update a UITableView.

    At the time when the block is called, the collection 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.

    Notifications are delivered via the standard run loop, and so can’t be delivered while the run loop is blocked by other activity. 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 dogs = realm.objects(Dog)
print("dogs.count: \(dogs?.count)") // => 0
let token = dogs.addNotificationBlock { (changes: RealmCollectionChange) in
    switch changes {
        case .Initial(let dogs):
            // Will print "dogs.count: 1"
            print("dogs.count: \(dogs.count)")
            break
        case .Update:
            // Will not be hit in this example
            break
        case .Error:
            break
    }
}
try! realm.write {
    let dog = Dog()
    dog.name = "Rex"
    person.dogs.append(dog)
}
// end of run loop execution context

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

    Warning

    This method cannot be called during a write transaction, or when the containing Realm is read-only.

    Declaration

    Swift

    public func addNotificationBlock(block: (RealmCollectionChange<Results> -> Void)) -> NotificationToken

    Parameters

    block

    The block to be called whenever a change occurs.

    Return Value

    A token which must be retained for as long as you want updates to be delivered.

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Sequence Support

  • Returns a GeneratorOf<T> that yields successive elements in the results.

    Declaration

    Swift

    public func generate() -> RLMGenerator<T>
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Collection Support

  • The position of the first element in a non-empty collection. Identical to endIndex in an empty collection.

    Declaration

    Swift

    public var startIndex: Int { return 0 }
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  • The collection’s past the end position. endIndex is not a valid argument to subscript, and is always reachable from startIndex by zero or more applications of successor().

    Declaration

    Swift

    public var endIndex: Int { return count }
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