Array.Reverse Method

Reference

Definition

Namespace:: System

Assembly:: System.Runtime.dll

Assembly:: mscorlib.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Reverses the order of the elements in a one-dimensional Array or in a portion of the Array.

Overloads

Reverse(Array)	Reverses the sequence of the elements in the entire one-dimensional Array.
Reverse(Array, Int32, Int32)	Reverses the sequence of a subset of the elements in the one-dimensional Array.
Reverse<T>(T[])	Reverses the sequence of the elements in the one-dimensional generic array.
Reverse<T>(T[], Int32, Int32)	Reverses the sequence of a subset of the elements in the one-dimensional generic array.

Reverse(Array)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Reverses the sequence of the elements in the entire one-dimensional Array.

public:
 static void Reverse(Array ^ array);

public static void Reverse (Array array);

static member Reverse : Array -> unit

Public Shared Sub Reverse (array As Array)

Parameters

array: Array

The one-dimensional Array to reverse.

Exceptions

ArgumentNullException

array is null.

RankException

array is multidimensional.

Examples

The following code example shows how to reverse the sort of the values in an Array.

using namespace System;
void PrintIndexAndValues( Array^ myArray );
void main()
{
   // Creates and initializes a new Array instance.
   Array^ myArray = Array::CreateInstance( String::typeid, 9 );
   myArray->SetValue( "The", 0 );
   myArray->SetValue( "quick", 1 );
   myArray->SetValue( "brown", 2 );
   myArray->SetValue( "fox", 3 );
   myArray->SetValue( "jumps", 4 );
   myArray->SetValue( "over", 5 );
   myArray->SetValue( "the", 6 );
   myArray->SetValue( "lazy", 7 );
   myArray->SetValue( "dog", 8 );

   // Displays the values of the Array.
   Console::WriteLine(  "The Array instance initially contains the following values:" );
   PrintIndexAndValues( myArray );

   // Reverses the sort of the values of the Array.
   Array::Reverse( myArray );
   
   // Displays the values of the Array.
   Console::WriteLine(  "After reversing:" );
   PrintIndexAndValues( myArray );
}

void PrintIndexAndValues( Array^ myArray )
{
   for ( int i = myArray->GetLowerBound( 0 ); i <= myArray->GetUpperBound( 0 ); i++ )
      Console::WriteLine(  "\t[{0}]:\t{1}", i, myArray->GetValue( i ) );
}

/* 
 This code produces the following output.
 
 The Array instance initially contains the following values:
     [0]:    The
     [1]:    quick
     [2]:    brown
     [3]:    fox
     [4]:    jumps
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 After reversing:
     [0]:    dog
     [1]:    lazy
     [2]:    the
     [3]:    over
     [4]:    jumps
     [5]:    fox
     [6]:    brown
     [7]:    quick
     [8]:    The
 */

open System

let printIndexAndValues (arr: 'a []) =
    for i = arr.GetLowerBound 0 to arr.GetUpperBound 0 do
        printfn $"\t[{i}]:\t{arr[i]}"

// Creates and initializes a new Array.
let myArray = 
    [| "The"; "quick"; "brown"; "fox"
       "jumps"; "over"; "the"; "lazy"; "dog" |]

// Displays the values of the Array.
printfn "The Array initially contains the following values:" 
printIndexAndValues myArray 

// Reverses the sort of the values of the Array.
Array.Reverse myArray 

// Displays the values of the Array.
printfn "After reversing:"
printIndexAndValues myArray 

(*
 This code produces the following output.

 The Array initially contains the following values:
     [0]:    The
     [1]:    quick
     [2]:    brown
     [3]:    fox
     [4]:    jumps
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 After reversing:
     [0]:    dog
     [1]:    lazy
     [2]:    the
     [3]:    over
     [4]:    jumps
     [5]:    fox
     [6]:    brown
     [7]:    quick
     [8]:    The
 *)

using System;
public class SamplesArray  {

   public static void Main()  {

      // Creates and initializes a new Array.
      Array myArray=Array.CreateInstance( typeof(string), 9 );
      myArray.SetValue( "The", 0 );
      myArray.SetValue( "quick", 1 );
      myArray.SetValue( "brown", 2 );
      myArray.SetValue( "fox", 3 );
      myArray.SetValue( "jumps", 4 );
      myArray.SetValue( "over", 5 );
      myArray.SetValue( "the", 6 );
      myArray.SetValue( "lazy", 7 );
      myArray.SetValue( "dog", 8 );

      // Displays the values of the Array.
      Console.WriteLine( "The Array initially contains the following values:" );
      PrintIndexAndValues( myArray );

      // Reverses the sort of the values of the Array.
      Array.Reverse( myArray );

      // Displays the values of the Array.
      Console.WriteLine( "After reversing:" );
      PrintIndexAndValues( myArray );
   }

   public static void PrintIndexAndValues( Array myArray )  {
      for ( int i = myArray.GetLowerBound(0); i <= myArray.GetUpperBound(0); i++ )
         Console.WriteLine( "\t[{0}]:\t{1}", i, myArray.GetValue( i ) );
   }
}
/*
This code produces the following output.

The Array initially contains the following values:
    [0]:    The
    [1]:    quick
    [2]:    brown
    [3]:    fox
    [4]:    jumps
    [5]:    over
    [6]:    the
    [7]:    lazy
    [8]:    dog
After reversing:
    [0]:    dog
    [1]:    lazy
    [2]:    the
    [3]:    over
    [4]:    jumps
    [5]:    fox
    [6]:    brown
    [7]:    quick
    [8]:    The
*/

Public Class SamplesArray    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new Array.
        Dim myArray As Array = Array.CreateInstance(GetType(String), 9)
        myArray.SetValue("The", 0)
        myArray.SetValue("quick", 1)
        myArray.SetValue("brown", 2)
        myArray.SetValue("fox", 3)
        myArray.SetValue("jumps", 4)
        myArray.SetValue("over", 5)
        myArray.SetValue("the", 6)
        myArray.SetValue("lazy", 7)
        myArray.SetValue("dog", 8)
        
        ' Displays the values of the Array.
        Console.WriteLine("The Array initially contains the " _
           + "following values:")
        PrintIndexAndValues(myArray)
        
        ' Reverses the sort of the values of the Array.
        Array.Reverse(myArray)
        
        ' Displays the values of the Array.
        Console.WriteLine("After reversing:")
        PrintIndexAndValues(myArray)
    End Sub
    
    
    
    Public Shared Sub PrintIndexAndValues(myArray As Array)
        Dim i As Integer
        For i = myArray.GetLowerBound(0) To myArray.GetUpperBound(0)
            Console.WriteLine(ControlChars.Tab + "[{0}]:" + ControlChars.Tab _
               + "{1}", i, myArray.GetValue(i))
        Next i
    End Sub
End Class

' This code produces the following output.
' 
' The Array initially contains the following values:
'     [0]:    The
'     [1]:    quick
'     [2]:    brown
'     [3]:    fox
'     [4]:    jumps
'     [5]:    over
'     [6]:    the
'     [7]:    lazy
'     [8]:    dog
' After reversing:
'     [0]:    dog
'     [1]:    lazy
'     [2]:    the
'     [3]:    over
'     [4]:    jumps
'     [5]:    fox
'     [6]:    brown
'     [7]:    quick
'     [8]:    The

Remarks

After a call to this method, the element at myArray[i], where i is any index in the array, moves to myArray[j], where j equals (myArray.Length + myArray.GetLowerBound(0)) - (i - myArray.GetLowerBound(0)) - 1.

This method is an O(n) operation, where n is the Length of array.

In F#, the Array.rev function can be used instead.

As the following example shows, the Reverse method can be used to reverse a jagged array. It initializes a jagged array with one element for each month of the current year in the current culture's calendar. Each element contains an array with as many elements as that month has days. The example displays the contents of the array, calls the Reverse method, and then displays the contents of the reversed array.

using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      int nMonths = DateTimeFormatInfo.CurrentInfo.Calendar.GetMonthsInYear(DateTime.Now.Year);
      int[][] months = new int[nMonths][];

      // Populate elements with number of days in month.
      for (int ctr = 0; ctr <= months.GetUpperBound(0); ctr++) {
         int daysInMonth = DateTime.DaysInMonth(DateTime.Now.Year, ctr + 1);
         months[ctr] = new int[daysInMonth] ;
         for (int ctr2 = 1; ctr2 <= daysInMonth; ctr2++)
            months[ctr][ctr2 - 1] = ctr2;
      }

      foreach (var month in months) {
         foreach (var day in month)
            Console.Write("{0} ", day);

         Console.WriteLine();
      }
      Console.WriteLine();

      Console.WriteLine("About to reverse array.\n");
      Array.Reverse(months);

      foreach (var month in months) {
         foreach (var day in month)
            Console.Write("{0} ", day);

         Console.WriteLine();
      }
   }
}
// The example displays output similar to the following:
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//
//    About to reverse array.
//
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

open System
open System.Globalization

let nMonths = DateTimeFormatInfo.CurrentInfo.Calendar.GetMonthsInYear DateTime.Now.Year

let months = Array.init nMonths (fun i -> 
    // Populate elements with number of days in month.
    let daysInMonth = DateTime.DaysInMonth(DateTime.Now.Year, i + 1)
    Array.init daysInMonth (fun i -> i + 1 ) )

for month in months do
    for day in month do
        printf $"{day} "
    printfn ""

printfn "\nAbout to reverse array.\n"
Array.Reverse months

for month in months do
    for day in month do
        printf $"{day} "
    printfn ""

// The example displays output similar to the following:
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    
//    About to reverse array.
//    
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 
//    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Imports System.Globalization

Module Example
   Public Sub Main()
      Dim nMonths As Integer = DateTimeFormatInfo.CurrentInfo.Calendar.GetMonthsInYear(Date.Now.Year)
      Dim months()() As Integer = New Integer(nMonths - 1)() {}

      ' Populate elements with number of days in month.
      For ctr As Integer = 0 To months.GetUpperBound(0)
         Dim daysInMonth As Integer = DateTime.DaysInMonth(Date.Now.Year, ctr + 1)
         months(ctr) = New Integer(daysInMonth - 1) {}
         For ctr2 As Integer = 1 To daysInMonth
            months(ctr)(ctr2 - 1) = ctr2
         Next
      Next

      For Each _month In months
         For each _day In _month
            Console.Write("{0} ", _day)
         Next   
         Console.WriteLine()
      Next
      Console.WriteLine()
               
      Console.WriteLine("About to reverse array.")
      Console.WriteLine()
      Array.Reverse(months)

      For Each _month In months
         For each _day In _month
            Console.Write("{0} ", _day)
         Next   
         Console.WriteLine()
      Next
   End Sub
End Module
' The example displays output similar to the following:
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    
'    About to reverse array.
'    
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29
'    1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31

Applies to

Reverse(Array, Int32, Int32)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Reverses the sequence of a subset of the elements in the one-dimensional Array.

public:
 static void Reverse(Array ^ array, int index, int length);

public static void Reverse (Array array, int index, int length);

static member Reverse : Array * int * int -> unit

Public Shared Sub Reverse (array As Array, index As Integer, length As Integer)

Parameters

array: Array

The one-dimensional Array to reverse.

index: Int32

The starting index of the section to reverse.

length: Int32

The number of elements in the section to reverse.

Exceptions

ArgumentNullException

array is null.

RankException

array is multidimensional.

ArgumentOutOfRangeException

index is less than the lower bound of array.

-or-

length is less than zero.

ArgumentException

index and length do not specify a valid range in array.

Examples

The following code example shows how to reverse the sort of the values in a range of elements in an Array.

using namespace System;
void PrintIndexAndValues( Array^ myArray );
void main()
{
   // Creates and initializes a new Array instance.
   Array^ myArray = Array::CreateInstance( String::typeid, 9 );
   myArray->SetValue( "The", 0 );
   myArray->SetValue( "QUICK", 1 );
   myArray->SetValue( "BROWN", 2 );
   myArray->SetValue( "FOX", 3 );
   myArray->SetValue( "jumps", 4 );
   myArray->SetValue( "over", 5 );
   myArray->SetValue( "the", 6 );
   myArray->SetValue( "lazy", 7 );
   myArray->SetValue( "dog", 8 );

   // Displays the values of the Array.
   Console::WriteLine(  "The Array instance initially contains the following values:" );
   PrintIndexAndValues( myArray );

   // Reverses the sort of the values of the Array.
   Array::Reverse( myArray, 1, 3 );

   // Displays the values of the Array.
   Console::WriteLine(  "After reversing:" );
   PrintIndexAndValues( myArray );
}

void PrintIndexAndValues( Array^ myArray )
{
   for ( int i = myArray->GetLowerBound( 0 ); i <= myArray->GetUpperBound( 0 ); i++ )
      Console::WriteLine(  "\t[{0}]:\t{1}", i, myArray->GetValue( i ) );
}

/* 
 This code produces the following output.
 
 The Array instance initially contains the following values:
     [0]:    The
     [1]:    QUICK
     [2]:    BROWN
     [3]:    FOX
     [4]:    jumps
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 After reversing:
     [0]:    The
     [1]:    FOX
     [2]:    BROWN
     [3]:    QUICK
     [4]:    jumps
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 */

open System

let printIndexAndValues (arr: 'a []) =
    for i = arr.GetLowerBound 0 to arr.GetUpperBound 0 do
        printfn $"\t[{i}]:\t{arr[i]}"

// Creates and initializes a new Array.
let myArray = 
    [| "The"; "QUICK"; "BROWN"; "FOX"
       "jumps"; "over"; "the"; "lazy"; "dog" |]

// Displays the values of the Array.
printfn "The Array initially contains the following values:" 
printIndexAndValues myArray 

// Reverses the sort of the values of the Array.
Array.Reverse(myArray, 1, 3)

// Displays the values of the Array.
printfn "After reversing:"
printIndexAndValues myArray 

(*
 This code produces the following output.

 The Array initially contains the following values:
     [0]:    The
     [1]:    QUICK
     [2]:    BROWN
     [3]:    FOX
     [4]:    jumps
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 After reversing:
     [0]:    The
     [1]:    FOX
     [2]:    BROWN
     [3]:    QUICK
     [4]:    jumps
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
 *)

using System;
public class SamplesArray1  {

   public static void Main()  {

      // Creates and initializes a new Array.
      Array myArray=Array.CreateInstance( typeof(string), 9 );
      myArray.SetValue( "The", 0 );
      myArray.SetValue( "QUICK", 1 );
      myArray.SetValue( "BROWN", 2 );
      myArray.SetValue( "FOX", 3 );
      myArray.SetValue( "jumps", 4 );
      myArray.SetValue( "over", 5 );
      myArray.SetValue( "the", 6 );
      myArray.SetValue( "lazy", 7 );
      myArray.SetValue( "dog", 8 );

      // Displays the values of the Array.
      Console.WriteLine( "The Array initially contains the following values:" );
      PrintIndexAndValues( myArray );

      // Reverses the sort of the values of the Array.
      Array.Reverse( myArray, 1, 3 );

      // Displays the values of the Array.
      Console.WriteLine( "After reversing:" );
      PrintIndexAndValues( myArray );
   }

   public static void PrintIndexAndValues( Array myArray )  {
      for ( int i = myArray.GetLowerBound(0); i <= myArray.GetUpperBound(0); i++ )
         Console.WriteLine( "\t[{0}]:\t{1}", i, myArray.GetValue( i ) );
   }
}
/*
This code produces the following output.

The Array initially contains the following values:
    [0]:    The
    [1]:    QUICK
    [2]:    BROWN
    [3]:    FOX
    [4]:    jumps
    [5]:    over
    [6]:    the
    [7]:    lazy
    [8]:    dog
After reversing:
    [0]:    The
    [1]:    FOX
    [2]:    BROWN
    [3]:    QUICK
    [4]:    jumps
    [5]:    over
    [6]:    the
    [7]:    lazy
    [8]:    dog
*/

Public Class SamplesArray    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new Array.
        Dim myArray As Array = Array.CreateInstance(GetType(String), 9)
        myArray.SetValue("The", 0)
        myArray.SetValue("QUICK", 1)
        myArray.SetValue("BROWN", 2)
        myArray.SetValue("FOX", 3)
        myArray.SetValue("jumps", 4)
        myArray.SetValue("over", 5)
        myArray.SetValue("the", 6)
        myArray.SetValue("lazy", 7)
        myArray.SetValue("dog", 8)
        
        ' Displays the values of the Array.
        Console.WriteLine("The Array initially contains the " _
           + "following values:")
        PrintIndexAndValues(myArray)
        
        ' Reverses the sort of the values of the Array.
        Array.Reverse(myArray, 1, 3)
        
        ' Displays the values of the Array.
        Console.WriteLine("After reversing:")
        PrintIndexAndValues(myArray)
    End Sub    
    
    
    Public Shared Sub PrintIndexAndValues(myArray As Array)
        Dim i As Integer
        For i = myArray.GetLowerBound(0) To myArray.GetUpperBound(0)
            Console.WriteLine(ControlChars.Tab + "[{0}]:" + ControlChars.Tab _
               + "{1}", i, myArray.GetValue(i))
        Next i
    End Sub
End Class

' This code produces the following output.
' 
' The Array initially contains the following values:
'     [0]:    The
'     [1]:    QUICK
'     [2]:    BROWN
'     [3]:    FOX
'     [4]:    jumps
'     [5]:    over
'     [6]:    the
'     [7]:    lazy
'     [8]:    dog
' After reversing:
'     [0]:    The
'     [1]:    FOX
'     [2]:    BROWN
'     [3]:    QUICK
'     [4]:    jumps
'     [5]:    over
'     [6]:    the
'     [7]:    lazy
'     [8]:    dog

Remarks

The Reverse method can be used to reverse a jagged array.

This method is an O(n) operation, where n is length.

Applies to

Reverse<T>(T[])

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Reverses the sequence of the elements in the one-dimensional generic array.

public:
generic <typename T>
 static void Reverse(cli::array <T> ^ array);

public static void Reverse<T> (T[] array);

static member Reverse : 'T[] -> unit

Public Shared Sub Reverse(Of T) (array As T())

Type Parameters

T

The type of the elements in array.

Parameters

array: T[]

The one-dimensional array of elements to reverse.

Exceptions

ArgumentNullException

array is null.

RankException

array is multidimensional.

Applies to

Reverse<T>(T[], Int32, Int32)

Source:: Array.cs

Source:: Array.cs

Source:: Array.cs

Reverses the sequence of a subset of the elements in the one-dimensional generic array.

public:
generic <typename T>
 static void Reverse(cli::array <T> ^ array, int index, int length);

public static void Reverse<T> (T[] array, int index, int length);

static member Reverse : 'T[] * int * int -> unit

Public Shared Sub Reverse(Of T) (array As T(), index As Integer, length As Integer)

Type Parameters

T

The type of the elements in array.

Parameters

array: T[]

The one-dimensional array of elements to reverse.

index: Int32

The starting index of the section to reverse.

length: Int32

The number of elements in the section to reverse.

Exceptions

ArgumentNullException

array is null.

RankException

array is multidimensional.

ArgumentOutOfRangeException

index is less than the lower bound of array.

-or-

length is less than zero.

ArgumentException

index and length do not specify a valid range in array.

Applies to

Share via

Array.Reverse Method

Definition

Overloads

Reverse(Array)

Parameters

Exceptions

Examples

Remarks

Applies to

Reverse(Array, Int32, Int32)

Parameters

Exceptions

Examples

Remarks

Applies to

Reverse<T>(T[])

Type Parameters

Parameters

Exceptions

Applies to

Reverse<T>(T[], Int32, Int32)

Type Parameters

Parameters

Exceptions

Applies to

Additional resources