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Observable.ToLookup(TSource, TKey) Method (IObservable(TSource), Func(TSource, TKey))

Creates a lookup from an observable sequence according to a specified key selector function.

Namespace:  System.Reactive.Linq
Assembly:  System.Reactive (in System.Reactive.dll)

static member ToLookup : 
        source:IObservable<'TSource> * 
        keySelector:Func<'TSource, 'TKey> -> IObservable<ILookup<'TKey, 'TSource>> 

Type Parameters

TSource

The type of source.

TKey

The type of key.

Parameters

source
Type: System.IObservable(TSource)
An observable sequence to create a lookup for.
keySelector
Type: System.Func(TSource, TKey)
A function to extract a key from each element.

Return Value

Type: System.IObservable(ILookup(TKey, TSource))
A lookup from an observable sequence according to a specified key selector function.

Usage Note

In Visual Basic and C#, you can call this method as an instance method on any object of type IObservable(TSource). When you use instance method syntax to call this method, omit the first parameter. For more information, see http://msdn.microsoft.com/en-us/library/bb384936(v=vs.103).aspx or http://msdn.microsoft.com/en-us/library/bb383977(v=vs.103).aspx.
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