CountByExtensionCountByTSource, TKey(IEnumerableTSource, FuncTSource, TKey) Method
Applies a key-generating function to each element of a sequence and returns a sequence of
unique keys and their number of occurrences in the original sequence.
Namespace: MoreLinq.ExtensionsAssembly: MoreLinq (in MoreLinq.dll) Version: 4.1.0+0e154ef592f33ce0f6f3d534a9eedee273f0ce72
public static IEnumerable<KeyValuePair<TKey, int>> CountBy<TSource, TKey>(
this IEnumerable<TSource> source,
Func<TSource, TKey> keySelector
)
<ExtensionAttribute>
Public Shared Function CountBy(Of TSource, TKey) (
source As IEnumerable(Of TSource),
keySelector As Func(Of TSource, TKey)
) As IEnumerable(Of KeyValuePair(Of TKey, Integer))
public:
[ExtensionAttribute]
generic<typename TSource, typename TKey>
static IEnumerable<KeyValuePair<TKey, int>>^ CountBy(
IEnumerable<TSource>^ source,
Func<TSource, TKey>^ keySelector
)
[<ExtensionAttribute>]
static member CountBy :
source : IEnumerable<'TSource> *
keySelector : Func<'TSource, 'TKey> -> IEnumerable<KeyValuePair<'TKey, int>>
- source IEnumerableTSource
- Source sequence.
- keySelector FuncTSource, TKey
- Function that transforms each item of source sequence into a key to be compared against the others.
- TSource
- Type of the elements of the source sequence.
- TKey
- Type of the projected element.
IEnumerableKeyValuePairTKey,
Int32A sequence of unique keys and their number of occurrences in the original sequence.In Visual Basic and C#, you can call this method as an instance method on any object of type
IEnumerableTSource. When you use instance method syntax to call this method, omit the first parameter. For more information, see
Extension Methods (Visual Basic) or
Extension Methods (C# Programming Guide).