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Array.LastIndexOf Method

Returns the index of the last occurrence of a value in a one-dimensional Array or in a portion of the Array.

Overload List

Searches for the specified object and returns the index of the last occurrence within the entire one-dimensional Array.

[Visual Basic] Overloads Public Shared Function LastIndexOf(Array, Object) As Integer
[C#] public static int LastIndexOf(Array, object);
[C++] public: static int LastIndexOf(Array*, Object*);
[JScript] public static function LastIndexOf(Array, Object) : int;

Searches for the specified object and returns the index of the last occurrence within the section of the one-dimensional Array that extends from the first element to the specified index.

[Visual Basic] Overloads Public Shared Function LastIndexOf(Array, Object, Integer) As Integer
[C#] public static int LastIndexOf(Array, object, int);
[C++] public: static int LastIndexOf(Array*, Object*, int);
[JScript] public static function LastIndexOf(Array, Object, int) : int;

Searches for the specified object and returns the index of the last occurrence within the section of the one-dimensional Array that contains the specified number of elements and ends at the specified index.

Supported by the .NET Compact Framework.

[Visual Basic] Overloads Public Shared Function LastIndexOf(Array, Object, Integer, Integer) As Integer
[C#] public static int LastIndexOf(Array, object, int, int);
[C++] public: static int LastIndexOf(Array*, Object*, int, int);
[JScript] public static function LastIndexOf(Array, Object, int, int) : int;

Example

The following code example shows how to determine the index of the last occurrence of a specified element in an array. Note that the LastIndexOf method is a backward search; therefore, count must be less than or equal to (startIndex- the lower bound of the array + 1).

[Visual Basic] 
Imports System
Imports Microsoft.VisualBasic

Public Class SamplesArray    
    
    Public Shared Sub Main()
        
        ' Creates and initializes a new Array with three elements of
        ' the same value.
        Dim myArray As Array = Array.CreateInstance(GetType(String), 12)
        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)
        myArray.SetValue("in", 9)
        myArray.SetValue("the", 10)
        myArray.SetValue("barn", 11)
        
        ' Displays the values of the Array.
        Console.WriteLine("The Array contains the following values:")
        PrintIndexAndValues(myArray)
        
        ' Searches for the last occurrence of the duplicated value.
        Dim myString As String = "the"
        Dim myIndex As Integer = Array.LastIndexOf(myArray, myString)
        Console.WriteLine("The last occurrence of ""{0}"" is at index {1}.", _
           myString, myIndex)
        
        ' Searches for the last occurrence of the duplicated value in the first
        ' section of the Array.
        myIndex = Array.LastIndexOf(myArray, myString, 8)
        Console.WriteLine("The last occurrence of ""{0}"" between the start " _
           + "and index 8 is at index {1}.", myString, myIndex)
        
        ' Searches for the last occurrence of the duplicated value in a section
        ' of the Array.  Note that the start index is greater than the end
        ' index because the search is done backward.
        myIndex = Array.LastIndexOf(myArray, myString, 10, 6)
        Console.WriteLine("The last occurrence of ""{0}"" between index 5 " _
           + "and index 10 is at index {1}.", myString, myIndex)
    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 contains the following values:
'     [0]:    the
'     [1]:    quick
'     [2]:    brown
'     [3]:    fox
'     [4]:    jumps
'     [5]:    over
'     [6]:    the
'     [7]:    lazy
'     [8]:    dog
'     [9]:    in
'     [10]:    the
'     [11]:    barn
' The last occurrence of "the" is at index 10.
' The last occurrence of "the" between the start and index 8 is at index 6.
' The last occurrence of "the" between index 5 and index 10 is at index 10. 

[C#] 
using System;
public class SamplesArray  {

   public static void Main()  {

      // Creates and initializes a new Array with three elements of the same value.
      Array myArray=Array.CreateInstance( typeof(String), 12 );
      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 );
      myArray.SetValue( "in", 9 );
      myArray.SetValue( "the", 10 );
      myArray.SetValue( "barn", 11 );

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

      // Searches for the last occurrence of the duplicated value.
      String myString = "the";
      int myIndex = Array.LastIndexOf( myArray, myString );
      Console.WriteLine( "The last occurrence of \"{0}\" is at index {1}.", myString, myIndex );

      // Searches for the last occurrence of the duplicated value in the first section of the Array.
      myIndex = Array.LastIndexOf( myArray, myString, 8 );
      Console.WriteLine( "The last occurrence of \"{0}\" between the start and index 8 is at index {1}.", myString, myIndex );

      // Searches for the last occurrence of the duplicated value in a section of the Array.
      // Note that the start index is greater than the end index because the search is done backward.
      myIndex = Array.LastIndexOf( myArray, myString, 10, 6 );
      Console.WriteLine( "The last occurrence of \"{0}\" between index 5 and index 10 is at index {1}.", myString, myIndex );
   }


   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 contains the following values:
    [0]:    the
    [1]:    quick
    [2]:    brown
    [3]:    fox
    [4]:    jumps
    [5]:    over
    [6]:    the
    [7]:    lazy
    [8]:    dog
    [9]:    in
    [10]:    the
    [11]:    barn
The last occurrence of "the" is at index 10.
The last occurrence of "the" between the start and index 8 is at index 6.
The last occurrence of "the" between index 5 and index 10 is at index 10.
*/

[C++] 
#using <mscorlib.dll>
using namespace System;

void PrintIndexAndValues( Array* myArray );
 
void main()  {
 
    // Creates and initializes a new Array instance with three elements of the same value.
    Array* myArray = Array::CreateInstance( __typeof(String), 12 );
    myArray->SetValue( S"the", 0 );
    myArray->SetValue( S"quick", 1 );
    myArray->SetValue( S"brown", 2 );
    myArray->SetValue( S"fox", 3 );
    myArray->SetValue( S"jumped", 4 );
    myArray->SetValue( S"over", 5 );
    myArray->SetValue( S"the", 6 );
    myArray->SetValue( S"lazy", 7 );
    myArray->SetValue( S"dog", 8 );
    myArray->SetValue( S"in", 9 );
    myArray->SetValue( S"the", 10 );
    myArray->SetValue( S"barn", 11 );
 
    // Displays the values of the Array.
    Console::WriteLine( "The Array instance contains the following values:" );
    PrintIndexAndValues( myArray );
 
    // Searches for the last occurrence of the duplicated value.
    String* myString = "the";
    int myIndex = Array::LastIndexOf( myArray, myString );
    Console::WriteLine( "The last occurrence of \"{0}\" is at index {1}.", myString, __box(myIndex) );
 
    // Searches for the last occurrence of the duplicated value in the first section of the Array.
    myIndex = Array::LastIndexOf( myArray, myString, 8 );
    Console::WriteLine( "The last occurrence of \"{0}\" between the start and index 8 is at index {1}.", myString, __box(myIndex));
 
    // Searches for the last occurrence of the duplicated value in a section of the Array.  
    // Note that the start index is greater than the end index because the search is done backward.
    myIndex = Array::LastIndexOf( myArray, myString, 10, 6 );
    Console::WriteLine( "The last occurrence of \"{0}\" between index 5 and index 10 is at index {1}.", myString, __box(myIndex));
}
 
 
void PrintIndexAndValues( Array* myArray ) {
    for ( int i = myArray->GetLowerBound(0); i <= myArray->GetUpperBound(0); i++ )
        Console::WriteLine( "\t[{0}]:\t{1}", __box(i), myArray->GetValue( i ) );
}

 /* 
 This code produces the following output.
 
 The Array instance contains the following values:
     [0]:    the
     [1]:    quick
     [2]:    brown
     [3]:    fox
     [4]:    jumped
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
     [9]:    in
     [10]:    the
     [11]:    barn
 The last occurrence of "the" is at index 10.
 The last occurrence of "the" between the start and index 8 is at index 6.
 The last occurrence of "the" between index 5 and index 10 is at index 10.
 */

[JScript] 
import System;

// Creates and initializes a new Array with three elements of the same value.
var myArray : System.Array= System.Array.CreateInstance( System.String, 12 );
myArray.SetValue( "the", 0 );
myArray.SetValue( "quick", 1 );
myArray.SetValue( "brown", 2 );
myArray.SetValue( "fox", 3 );
myArray.SetValue( "jumped", 4 );
myArray.SetValue( "over", 5 );
myArray.SetValue( "the", 6 );
myArray.SetValue( "lazy", 7 );
myArray.SetValue( "dog", 8 );
myArray.SetValue( "in", 9 );
myArray.SetValue( "the", 10 );
myArray.SetValue( "barn", 11 );

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

// Searches for the last occurrence of the duplicated value.
var myString : String = "the";
var myIndex : int = System.Array.LastIndexOf( myArray, myString );
Console.WriteLine( "The last occurrence of \"{0}\" is at index {1}.", myString, myIndex );

// Searches for the last occurrence of the duplicated value in the first section of the Array.
myIndex = System.Array.LastIndexOf( myArray, myString, 8 );
Console.WriteLine( "The last occurrence of \"{0}\" between the start and index 8 is at index {1}.", myString, myIndex );

// Searches for the last occurrence of the duplicated value in a section of the Array. 
// Note that the start index is greater than the end index because the search is done backward.
myIndex = System.Array.LastIndexOf( myArray, myString, 10, 6 );
Console.WriteLine( "The last occurrence of \"{0}\" between index 5 and index 10 is at index {1}.", myString, myIndex );
 
 
function PrintIndexAndValues( myArray : System.Array )  {
   for ( var i : int = 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 contains the following values:
     [0]:    the
     [1]:    quick
     [2]:    brown
     [3]:    fox
     [4]:    jumped
     [5]:    over
     [6]:    the
     [7]:    lazy
     [8]:    dog
     [9]:    in
     [10]:    the
     [11]:    barn
 The last occurrence of "the" is at index 10.
 The last occurrence of "the" between the start and index 8 is at index 6.
 The last occurrence of "the" between index 5 and index 10 is at index 10.
 */

See Also

Array Class | Array Members | System Namespace

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