LinqExtensions.GroupBy<T, TKey, TElement, TResult>(Vector<T>, Func<T, TKey>, Func<T, TElement>, Func<TKey, IEnumerable<TElement>, TResult>, IEqualityComparer<TKey>) Method

Groups the elements of a vector according to the specified key selector function and creates a result value from each group and its key. Key values are compared using the specified comparer, and the elements of each group are projected using the specified function.

Definition

Namespace: Extreme.DataAnalysis.Linq
Assembly: Extreme.Numerics (in Extreme.Numerics.dll) Version: 8.1.23

public static Vector<TResult> GroupBy<T, TKey, TElement, TResult>(
	this Vector<T> vector,
	Func<T, TKey> keySelector,
	Func<T, TElement> elementSelector,
	Func<TKey, IEnumerable<TElement>, TResult> resultSelector,
	IEqualityComparer<TKey> comparer
)

Visual Basic

<ExtensionAttribute>
Public Shared Function GroupBy(Of T, TKey, TElement, TResult) ( 
	vector As Vector(Of T),
	keySelector As Func(Of T, TKey),
	elementSelector As Func(Of T, TElement),
	resultSelector As Func(Of TKey, IEnumerable(Of TElement), TResult),
	comparer As IEqualityComparer(Of TKey)
) As Vector(Of TResult)

C++/CLI

public:
[ExtensionAttribute]
generic<typename T, typename TKey, typename TElement, typename TResult>
static Vector<TResult>^ GroupBy(
	Vector<T>^ vector, 
	Func<T, TKey>^ keySelector, 
	Func<T, TElement>^ elementSelector, 
	Func<TKey, IEnumerable<TElement>^, TResult>^ resultSelector, 
	IEqualityComparer<TKey>^ comparer
)

[<ExtensionAttribute>]
static member GroupBy : 
        vector : Vector<'T> * 
        keySelector : Func<'T, 'TKey> * 
        elementSelector : Func<'T, 'TElement> * 
        resultSelector : Func<'TKey, IEnumerable<'TElement>, 'TResult> * 
        comparer : IEqualityComparer<'TKey> -> Vector<'TResult>

Parameters

vector Vector<T>: A vector whose elements to group.
keySelector Func<T, TKey>: A function to extract the key for each element.
elementSelector Func<T, TElement>: A function that maps each input element to an element in a grouping.
resultSelector Func<TKey, IEnumerable<TElement>, TResult>: A function that maps each group to a final result.
comparer IEqualityComparer<TKey>: An object that compares two keys for equality.

Type Parameters

T: The type of the elements of the vector.
TKey: The type of the keys.
TElement: The type of the elements in each grouping.
TResult: The type of the final result for each group.

Return Value

Vector<TResult>
A vector of elements of type TResult where each element is obtained by applying resultSelector to each group resulting from using keySelector to obtain the key and elementSelector to obtain the values on each element of vector.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type Vector<T>. 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).