Windows apps
Collapse the table of content
Expand the table of content
Information
The topic you requested is included in another documentation set. For convenience, it's displayed below. Choose Switch to see the topic in its original location.

Enumerable.Where<'TSource> Method (IEnumerable<'TSource>, Func<'TSource, Int32, Boolean>)

 

Filters a sequence of values based on a predicate. Each element's index is used in the logic of the predicate function.

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

static member Where<'TSource> : 
        source:IEnumerable<'TSource> *
        predicate:Func<'TSource, int, bool> -> IEnumerable<'TSource>

Parameters

source
Type: System.Collections.Generic.IEnumerable<'TSource>

An IEnumerable<'T> to filter.

predicate
Type: System.Func<'TSource, Int32, Boolean>

A function to test each source element for a condition; the second parameter of the function represents the index of the source element.

Return Value

Type: System.Collections.Generic.IEnumerable<'TSource>

An IEnumerable<'T> that contains elements from the input sequence that satisfy the condition.

Type Parameters

TSource

The type of the elements of source.

Exception Condition
ArgumentNullException

source or predicate is null.

This method is implemented by using deferred execution. The immediate return value is an object that stores all the information that is required to perform the action. The query represented by this method is not executed until the object is enumerated either by calling its GetEnumerator method directly or by using foreach in Visual C# or For Each in Visual Basic.

The first argument of predicate represents the element to test. The second argument represents the zero-based index of the element within source.

The following code example demonstrates how to use Where<'TSource>(IEnumerable<'TSource>, Func<'TSource, Int32, Boolean>) to filter a sequence based on a predicate that involves the index of each element.

No code example is currently available or this language may not be supported.

Universal Windows Platform
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
Return to top
Show:
© 2016 Microsoft