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

CollectionTRecord, TTimeCountTKey Method (ExpressionFuncTRecord, TKey)

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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

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

keySelector: Type: System.Linq.ExpressionsExpressionFuncTRecord, TKey
Function that extracts a key from each record.

Type: CollectionPairTKey, Int64, TTime
The collection of pairs of keys and the respective counts for each group.