DryadLinqExtension.MapReduce(TSource, TMap, TKey, TResult) Method

DryadLinqExtension MapReduce TSource, TMap, TKey, TResult Method

DryadLINQ documentation

The standard MapReduce.

Namespace: Microsoft.Research.DryadLinq
Assembly: Microsoft.Research.DryadLinq (in Microsoft.Research.DryadLinq.dll) Version: 0.1.2.0 (0.1.2.0)

Syntax

C++

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public static IQueryable<TResult> MapReduce<TSource, TMap, TKey, TResult>(
	this IQueryable<TSource> source,
	Expression<Func<TSource, IEnumerable<TMap>>> mapper,
	Expression<Func<TMap, TKey>> keySelector,
	Expression<Func<TKey, IEnumerable<TMap>, TResult>> reducer
)

public static IQueryable<TResult> MapReduce<TSource, TMap, TKey, TResult>(
	this IQueryable<TSource> source,
	Expression<Func<TSource, IEnumerable<TMap>>> mapper,
	Expression<Func<TMap, TKey>> keySelector,
	Expression<Func<TKey, IEnumerable<TMap>, TResult>> reducer
)

<ExtensionAttribute> 
Public Shared Function MapReduce(Of TSource, TMap, TKey, TResult) ( 
	source As IQueryable(Of TSource),
	mapper As Expression(Of Func(Of TSource, IEnumerable(Of TMap))),
	keySelector As Expression(Of Func(Of TMap, TKey)),
	reducer As Expression(Of Func(Of TKey, IEnumerable(Of TMap), TResult))
) As IQueryable(Of TResult)

<ExtensionAttribute> 
Public Shared Function MapReduce(Of TSource, TMap, TKey, TResult) ( 
	source As IQueryable(Of TSource),
	mapper As Expression(Of Func(Of TSource, IEnumerable(Of TMap))),
	keySelector As Expression(Of Func(Of TMap, TKey)),
	reducer As Expression(Of Func(Of TKey, IEnumerable(Of TMap), TResult))
) As IQueryable(Of TResult)

public:
[ExtensionAttribute]
generic<typename TSource, typename TMap, typename TKey, typename TResult>
static IQueryable<TResult>^ MapReduce(
	IQueryable<TSource>^ source, 
	Expression<Func<TSource, IEnumerable<TMap>^>^>^ mapper, 
	Expression<Func<TMap, TKey>^>^ keySelector, 
	Expression<Func<TKey, IEnumerable<TMap>^, TResult>^>^ reducer
)

public:
[ExtensionAttribute]
generic<typename TSource, typename TMap, typename TKey, typename TResult>
static IQueryable<TResult>^ MapReduce(
	IQueryable<TSource>^ source, 
	Expression<Func<TSource, IEnumerable<TMap>^>^>^ mapper, 
	Expression<Func<TMap, TKey>^>^ keySelector, 
	Expression<Func<TKey, IEnumerable<TMap>^, TResult>^>^ reducer
)

Parameters

source: Type: System.Linq IQueryable TSource
The input dataset

mapper: Type: System.Linq.Expressions Expression Func TSource, IEnumerable TMap
The map function

keySelector: Type: System.Linq.Expressions Expression Func TMap, TKey
The key extraction function

reducer: Type: System.Linq.Expressions Expression Func TKey, IEnumerable TMap , TResult
The reduce function

Type Parameters

TSource: The type of the records of input dataset
TMap: The type of the resulting records of mapper
TKey: The type of the keys for hash exchange
TResult: The type of the resulting records of reducer

Return Value

Type: IQueryable TResult
The result dataset of MapReduce

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable TSource . 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).