Collection(TRecord, TTime).Count(TKey, TOutput) Method (Expression(Func(TRecord, TKey)), Expression(Func(TKey, Int64, TOutput)))

CollectionTRecord, TTimeCountTKey, TOutput Method (ExpressionFuncTRecord, TKey, ExpressionFuncTKey, Int64, TOutput)

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[This is preliminary documentation and is subject to change.]

Groups records using the supplied key selector, and counts the number of records in each group.

Namespace: Microsoft.Research.Naiad.Frameworks.DifferentialDataflow
Assembly: Microsoft.Research.Naiad.DifferentialDataflow (in Microsoft.Research.Naiad.DifferentialDataflow.dll) Version: 0.5.0.0 (0.5.0.0)

Syntax

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Collection<TOutput, TTime> Count<TKey, TOutput>(
	Expression<Func<TRecord, TKey>> keySelector,
	Expression<Func<TKey, long, TOutput>> resultSelector
)
where TKey : Object, IEquatable<TKey>
where TOutput : Object, IEquatable<TOutput>

Parameters

keySelector: Type: System.Linq.ExpressionsExpressionFuncTRecord, TKey
Function that extracts a key from each record.
resultSelector: Type: System.Linq.ExpressionsExpressionFuncTKey, Int64, TOutput
Function that transforms a key and count to an output record.

Type Parameters

TKey: The key type.
TOutput: The output type.

Return Value

Type: CollectionTOutput, TTime
The collection of output records.

Reference

CollectionTRecord, TTime Interface

Count Overload

Microsoft.Research.Naiad.Frameworks.DifferentialDataflow Namespace