Observable.Select<TSource, TResult> Method (IObservable<TSource>, Func<TSource, Int32, TResult>)

Projects each element of an observable sequence into a new form by incorporating the element’s index with the specified source and selector.

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

public static IObservable<TResult> Select<TSource, TResult>(
	this IObservable<TSource> source,
	Func<TSource, int, TResult> selector

Type Parameters


The type of source.


The type of result.


Type: System.IObservable<TSource>
A sequence of elements to invoke a transform function on.
Type: System.Func<TSource, Int32, TResult>
A transform function to apply to each source element.

Return Value

Type: System.IObservable<TResult>
An observable sequence into a new form.

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 https://msdn.microsoft.com/en-us/library/bb384936(v=vs.103).aspx or https://msdn.microsoft.com/en-us/library/bb383977(v=vs.103).aspx.