[This is preliminary documentation and is subject to change.]
Groups records using the supplied key selector, and applies the given aggregation function.
Namespace: Microsoft.Research.Naiad.Frameworks.Lindi
Assembly: Microsoft.Research.Naiad.Lindi (in Microsoft.Research.Naiad.Lindi.dll) Version: 0.5.0.0 (0.5.0.0)
Syntax
C#
public static Stream<TOutput, TTime> Aggregate<TInput, TKey, TState, TOutput, TTime>( this Stream<TInput, TTime> stream, Func<TInput, TKey> keySelector, Func<TInput, TState> stateSelector, Func<TState, TState, TState> combiner, Func<TKey, TState, TOutput> resultSelector ) where TTime : Object, Time<TTime>
Parameters
- stream
- Type: Microsoft.Research.NaiadStreamTInput, TTime
The input stream. - keySelector
- Type: SystemFuncTInput, TKey
Function that extracts a key from each record. - stateSelector
- Type: SystemFuncTInput, TState
Function that extracts from each record the state to be aggregated. - combiner
- Type: SystemFuncTState, TState, TState
A function from current state and incoming update, to the new state. - resultSelector
- Type: SystemFuncTKey, TState, TOutput
Function that transforms a key and final combined state to an output record.
Type Parameters
- TInput
- The type of the input records.
- TKey
- The key type.
- TState
- The intermediate state type.
- TOutput
- The type of the output records.
- TTime
- The type of timestamp on each record.
Return Value
Type: StreamTOutput, TTimeThe stream of output records.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type StreamTInput, TTime. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).See Also