Enumerable.Reverse(Of TSource) Method (IEnumerable(Of TSource))
Inverts the order of the elements in a sequence.
Assembly: System.Core (in System.Core.dll)
<ExtensionAttribute> Public Shared Function Reverse(Of TSource) ( source As IEnumerable(Of TSource) ) As IEnumerable(Of TSource)
Parameters
- source
-
Type:
System.Collections.Generic.IEnumerable(Of TSource)
A sequence of values to reverse.
Return Value
Type: System.Collections.Generic.IEnumerable(Of TSource)A sequence whose elements correspond to those of the input sequence in reverse order.
Type Parameters
- TSource
The type of the elements of source.
| Exception | Condition |
|---|---|
| ArgumentNullException | source 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.
Unlike OrderBy, this sorting method does not consider the actual values themselves in determining the order. Rather, it just returns the elements in the reverse order from which they are produced by the underlying source.
The following code example demonstrates how to use Reverse(Of TSource) to reverse the order of elements in an array.
' Create a List of Char values. Dim appleLetters As New List(Of Char)(New Char() _ {"a"c, "P"c, "P"c, "L"c, "E"c}) ' Reverse the order of the elements in the list. ' (We have to call AsEnumerable() in order to ' use System.Linq.Enumerable's Reverse() method. Dim reversed() As Char = appleLetters.AsEnumerable().Reverse().ToArray() Dim output As New System.Text.StringBuilder For Each chr As Char In reversed output.Append(chr & " ") Next ' Display the output. MsgBox(output.ToString()) ' This code produces the following output: ' ' E L P P a
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