Groups in parallel the elements of a sequence according to a specified key selector function and compares the keys by using a specified comparer.
Namespace:
System.Linq
Assembly:
System.Threading (in System.Threading.dll)
Syntax
| Visual Basic (Declaration) |
|---|
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)) |
| C# |
|---|
public static ParallelQuery<IGrouping<TKey, TSource>> GroupBy<TSource, TKey>(
ParallelQuery<TSource> source,
Func<TSource, TKey> keySelector,
IEqualityComparer<TKey> comparer
)
|
Parameters
- source
- Type: System.Linq..::.ParallelQuery<(Of <(TSource>)>)
An OrderedParallelQuery{TSource} than 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{TSource} to compare keys.
Type Parameters
- TSource
- The type of elements of source.
- TKey
- The type of the key returned by keySelector>.
Return Value
An OrderedParallelQuery{TSource} whose elements are sorted
descending according to a key.
Exceptions
| Exception | Condition |
|---|
| System..::.ArgumentNullException |
source or keySelector is a null reference (Nothing in Visual Basic).
|
See Also
