[This is preliminary documentation and is subject to change.]
Groups records using the supplied key selector, and applies the given reduction 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> GroupBy<TInput, TKey, TOutput, TTime>( this Stream<TInput, TTime> stream, Func<TInput, TKey> keySelector, Func<TKey, IEnumerable<TInput>, IEnumerable<TOutput>> reducer ) where TTime : Object, Time<TTime>
Parameters
- stream
- Type: Microsoft.Research.Naiad.Stream<TInput, TTime>
The input stream. - keySelector
- Type: System.Func<TInput, TKey>
Function that extracts a key from each record. - reducer
- Type: System.Func<TKey, IEnumerable<TInput>, IEnumerable<TOutput>>
Function that transforms a key and sequence of input records to a sequence of output records.
Type Parameters
- TInput
- The type of the input records.
- TKey
- The key type.
- TOutput
- The result type.
- TTime
- The type of timestamp on each record.
Return Value
Type: Stream<TOutput, TTime>The stream of output records for each group in stream.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type Stream<TInput, 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