MoreEnumerableGroupAdjacentTSource, TKey, TResult(IEnumerableTSource, FuncTSource, TKey, FuncTKey, IEnumerableTSource, TResult, IEqualityComparerTKey) Method

Groups the adjacent elements of a sequence according to a specified key selector function. The keys are compared by using a comparer and each group's elements are projected by using a specified function.

Definition

Namespace: MoreLinq
Assembly: MoreLinq (in MoreLinq.dll) Version: 3.4.0+b99a6a8cc504caf2d48372fe54a2f8116c59cd0c

C#

public static IEnumerable<TResult> GroupAdjacent<TSource, TKey, TResult>(
	this IEnumerable<TSource> source,
	Func<TSource, TKey> keySelector,
	Func<TKey, IEnumerable<TSource>, TResult> resultSelector,
	IEqualityComparer<TKey>? comparer
)

VB

<ExtensionAttribute>
Public Shared Function GroupAdjacent(Of TSource, TKey, TResult) ( 
	source As IEnumerable(Of TSource),
	keySelector As Func(Of TSource, TKey),
	resultSelector As Func(Of TKey, IEnumerable(Of TSource), TResult),
	comparer As IEqualityComparer(Of TKey)
) As IEnumerable(Of TResult)

C++

public:
[ExtensionAttribute]
generic<typename TSource, typename TKey, typename TResult>
static IEnumerable<TResult>^ GroupAdjacent(
	IEnumerable<TSource>^ source, 
	Func<TSource, TKey>^ keySelector, 
	Func<TKey, IEnumerable<TSource>^, TResult>^ resultSelector, 
	IEqualityComparer<TKey>^ comparer
)

F#

[<ExtensionAttribute>]
static member GroupAdjacent : 
        source : IEnumerable<'TSource> * 
        keySelector : Func<'TSource, 'TKey> * 
        resultSelector : Func<'TKey, IEnumerable<'TSource>, 'TResult> * 
        comparer : IEqualityComparer<'TKey> -> IEnumerable<'TResult>

Parameters

source IEnumerableTSource: A sequence whose elements to group.
keySelector FuncTSource, TKey: A function to extract the key for each element.
resultSelector FuncTKey, IEnumerableTSource, TResult: A function to map each key and associated source elements to a result object.
comparer IEqualityComparerTKey: An IEqualityComparerT to compare keys.

Type Parameters

TSource: The type of the elements of source.
TKey: The type of the key returned by keySelector.
TResult: The type of the elements in the resulting sequence.

Return Value

IEnumerableTResult
A collection of elements of type TResult where each element represents a projection over a group and its key.

Usage Note

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).

Remarks

This method is implemented by using deferred execution and streams the groupings. The grouping elements, however, are buffered. Each grouping is therefore yielded as soon as it is complete and before the next grouping occurs.