MoreEnumerableScanByTSource, TKey, TState(IEnumerableTSource, FuncTSource, TKey, FuncTKey, TState, FuncTState, TKey, TSource, TState, IEqualityComparerTKey) Method

Applies an accumulator function over sequence element keys, returning the keys along with intermediate accumulator states. An additional parameter specifies the comparer to use to compare keys.

Definition

Namespace: MoreLinq
Assembly: MoreLinq (in MoreLinq.dll) Version: 4.0.0+092a40d82a1b280568ffa006d9a210bdec0792cd

C#

public static IEnumerable<KeyValuePair<TKey, TState>> ScanBy<TSource, TKey, TState>(
	this IEnumerable<TSource> source,
	Func<TSource, TKey> keySelector,
	Func<TKey, TState> seedSelector,
	Func<TState, TKey, TSource, TState> accumulator,
	IEqualityComparer<TKey>? comparer
)

VB

<ExtensionAttribute>
Public Shared Function ScanBy(Of TSource, TKey, TState) ( 
	source As IEnumerable(Of TSource),
	keySelector As Func(Of TSource, TKey),
	seedSelector As Func(Of TKey, TState),
	accumulator As Func(Of TState, TKey, TSource, TState),
	comparer As IEqualityComparer(Of TKey)
) As IEnumerable(Of KeyValuePair(Of TKey, TState))

C++

public:
[ExtensionAttribute]
generic<typename TSource, typename TKey, typename TState>
static IEnumerable<KeyValuePair<TKey, TState>>^ ScanBy(
	IEnumerable<TSource>^ source, 
	Func<TSource, TKey>^ keySelector, 
	Func<TKey, TState>^ seedSelector, 
	Func<TState, TKey, TSource, TState>^ accumulator, 
	IEqualityComparer<TKey>^ comparer
)

F#

[<ExtensionAttribute>]
static member ScanBy : 
        source : IEnumerable<'TSource> * 
        keySelector : Func<'TSource, 'TKey> * 
        seedSelector : Func<'TKey, 'TState> * 
        accumulator : Func<'TState, 'TKey, 'TSource, 'TState> * 
        comparer : IEqualityComparer<'TKey> -> IEnumerable<KeyValuePair<'TKey, 'TState>>

Parameters

source IEnumerableTSource: The source sequence.
keySelector FuncTSource, TKey: A function that returns the key given an element.
seedSelector FuncTKey, TState: A function to determine the initial value for the accumulator that is invoked once per key encountered.
accumulator FuncTState, TKey, TSource, TState: An accumulator function invoked for each element.
comparer IEqualityComparerTKey: The equality comparer to use to determine whether or not keys are equal. If null, the default equality comparer for TSource is used.

Type Parameters

TSource: Type of the elements of the source sequence.
TKey: The type of the key.
TState: Type of the state.

Return Value

IEnumerableKeyValuePairTKey, TState
A sequence of keys paired with intermediate accumulator states.

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).