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

Collection<TOutput, TTime> Sum<TKey, TOutput>(
	Expression<Func<TRecord, TKey>> keySelector,
	Expression<Func<TRecord, double>> valueSelector,
	Expression<Func<TKey, double, 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.

valueSelector

Type: System.Linq.ExpressionsExpressionFuncTRecord, Double
Function that extracts the 64-bit floating-point value to be summed each record.

resultSelector

Type: System.Linq.ExpressionsExpressionFuncTKey, Double, TOutput
Function that transforms a key and count to an output record.

Type Parameters

TKey

The key type.

TOutput

The output type.

Return Value

Reference