Enumerable.Reverse<TSource>(IEnumerable<TSource>) Method
Definition
Important
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Inverts the order of the elements in a sequence.
public:
generic <typename TSource>
[System::Runtime::CompilerServices::Extension]
static System::Collections::Generic::IEnumerable<TSource> ^ Reverse(System::Collections::Generic::IEnumerable<TSource> ^ source);public static System.Collections.Generic.IEnumerable<TSource> Reverse<TSource> (this System.Collections.Generic.IEnumerable<TSource> source);static member Reverse : seq<'Source> -> seq<'Source><Extension()>
Public Function Reverse(Of TSource) (source As IEnumerable(Of TSource)) As IEnumerable(Of TSource)Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- IEnumerable<TSource>
A sequence of values to reverse.
Returns
A sequence whose elements correspond to those of the input sequence in reverse order.
Exceptions
source is null.
Examples
The following code example demonstrates how to use Reverse to reverse the order of elements in an array.
char[] apple = { 'a', 'p', 'p', 'l', 'e' };
char[] reversed = apple.Reverse().ToArray();
foreach (char chr in reversed)
{
Console.Write(chr + " ");
}
Console.WriteLine();
/*
This code produces the following output:
e l p p a
*/
' 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.
Console.WriteLine(output.ToString())
' This code produces the following output:
'
' E L P P a
Remarks
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 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.
