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.
-
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
. -
The type of the objects contained in the collection.
Declaration
Swift
public typealias Element = T
-
The Realm which manages this results collection. Note that this property will never return
nil
.Declaration
Swift
public var realm: Realm?
-
Indicates if the results collection is no longer valid.
The results collection becomes invalid if
invalidate
is called on the containingrealm
. An invalidated results collection can be accessed, but will always be empty.Declaration
Swift
public var invalidated: Bool
-
The number of objects in the results collection.
Declaration
Swift
public var count: Int
-
Returns the index of an object in the results collection, or
nil
if the object is not present.Declaration
Swift
public func indexOf(object: T) -> Int?
Parameters
object
An object.
-
Returns the index of the first object matching the predicate, or
nil
if no objects match.Declaration
Swift
public func indexOf(predicate: NSPredicate) -> Int?
Parameters
predicate
The predicate with which to filter the objects.
-
Returns the index of the first object matching the predicate, or
nil
if no objects match.Declaration
Swift
public func indexOf(predicateFormat: String, _ args: AnyObject...) -> Int?
Parameters
predicateFormat
A predicate format string, optionally followed by a variable number of arguments.`
-
Returns the first object in the results collection, or
nil
if the collection is empty.Declaration
Swift
public var first: T?
-
Returns the last object in the results collection, or
nil
if the collection is empty.Declaration
Swift
public var last: T?
-
Returns an
Array
containing the results of invokingvalueForKey(_:)
withkey
on each of the results collection’s objects.Declaration
Swift
public override func valueForKey(key: String) -> AnyObject?
Parameters
key
The name of the property whose values are desired.
-
Returns an
Array
containing the results of invokingvalueForKeyPath(_:)
withkeyPath
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 whose values are desired.
-
Invokes
setValue(_:forKey:)
on each of the results collection’s objects using the specifiedvalue
andkey
.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 whose value should be set on each object.
-
Returns a
Results
containing all objects matching the given predicate in the results 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.
-
Returns a
Results
containing all objects matching the given predicate in the results collection.Declaration
Swift
public func filter(predicate: NSPredicate) -> Results<T>
Parameters
predicate
The predicate with which to filter the objects.
-
Returns a
Results
containing the objects in the results collection, but sorted.Objects are sorted based on the values of the given property. For example, to sort a collection of
Student
s from youngest to oldest based on theirage
property, you might callstudents.sorted("age", ascending: true)
.Warning
Collections may only be sorted by properties of boolean,
NSDate
, single and double-precision floating point, integer, and string types.Declaration
Swift
public func sorted(property: String, ascending: Bool = true) -> Results<T>
Parameters
property
The name of the property to sort by.
ascending
The direction to sort in.
-
Returns a
Results
containing the objects in the results collection, but sorted.Warning
Collections may only be sorted by properties of boolean,
NSDate
, single and double-precision floating point, integer, and string types.Declaration
Swift
public func sorted<S: SequenceType where S.Generator.Element == SortDescriptor>(sortDescriptors: S) -> Results<T>
Parameters
sortDescriptors
A sequence of
SortDescriptor
s to sort by.
-
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. -
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. -
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.
-
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.
-
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 theRealmCollectionChange
documentation for more information on the change information supplied and an example of how to use it to update aUITableView
.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.self) 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.
-
Returns an
RLMGenerator
that yields successive elements in the results.Declaration
Swift
public func generate() -> RLMGenerator<T>
-
The position of the first element in a non-empty collection. Identical to
endIndex
in an empty collection.Declaration
Swift
public var startIndex: Int
-
The collection’s
past the end
position.endIndex
is not a valid argument tosubscript
, and is always reachable fromstartIndex
by zero or more applications ofsuccessor()
.Declaration
Swift
public var endIndex: Int