ParallelEnumerable.GroupBy(Of TSource, TKey) Method (ParallelQuery(Of TSource), Func(Of TSource, TKey), IEqualityComparer(Of TKey))

.NET Framework (current version)
 

Groups in parallel the elements of a sequence according to a specified key selector function and compares the keys by using a specified IComparer(Of T).

Namespace:   System.Linq
Assembly:  System.Core (in System.Core.dll)

<ExtensionAttribute>
Public Shared Function GroupBy(Of TSource, TKey) (
	source As ParallelQuery(Of TSource),
	keySelector As Func(Of TSource, TKey),
	comparer As IEqualityComparer(Of TKey)
) As ParallelQuery(Of IGrouping(Of TKey, TSource))

Parameters

source
Type: System.Linq.ParallelQuery(Of TSource)

An OrderedParallelQuery(Of TSource) that contains elements to sort.

keySelector
Type: System.Func(Of TSource, TKey)

A function to extract a key from an element.

comparer
Type: System.Collections.Generic.IEqualityComparer(Of TKey)

An IComparer(Of T) to compare keys.

Return Value

Type: System.Linq.ParallelQuery(Of IGrouping(Of TKey, TSource))

A sequence of groups that are sorted descending according to TKey.

Type Parameters

TSource

The type of elements of source.

TKey

The type of the key returned by keySelector>.

Exception Condition
OperationCanceledException

The query was canceled with the token passed in through WithCancellation.

ArgumentNullException

source or action is a null reference (Nothing in Visual Basic).

AggregateException

One or more exceptions occurred during the evaluation of the query.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1
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