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String.LastIndexOf Method (String, Int32, Int32)

.NET Framework 1.1

Reports the index position of the last occurrence of a specified String within this instance. The search starts at a specified character position and examines a specified number of character positions.

[Visual Basic]
Overloads Public Function LastIndexOf( _
   ByVal value As String, _
   ByVal startIndex As Integer, _
   ByVal count As Integer _
) As Integer
[C#]
public int LastIndexOf(
 string value,
 int startIndex,
 int count
);
[C++]
public: int LastIndexOf(
 String* value,
 int startIndex,
 int count
);
[JScript]
public function LastIndexOf(
   value : String,
 startIndex : int,
 count : int
) : int;

Parameters

value
The String to seek.
startIndex
The search starting position.
count
The number of character positions to examine.

Return Value

The index position of value if that string is found, or -1 if it is not. If value is Empty, the return value is startIndex.

Exceptions

Exception Type Condition
ArgumentNullException value is a null reference (Nothing in Visual Basic).
ArgumentOutOfRangeException count or startIndex is negative.

-or-

count plus startIndex specify a position not within this instance.

Remarks

Index numbering starts from zero.

This method performs a word (case-sensitive and culture-sensitive) search using the current culture. The search begins at the startIndex character position of this instance and proceeds backwards towards the beginning until either value is found or count character positions have been examined.

Example

[Visual Basic] 
' Sample for String.LastIndexOf(String, Int32, Int32)
Imports System
 _

Class Sample
   
   Public Shared Sub Main()
      
      Dim br1 As String = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-"
      Dim br2 As String = "0123456789012345678901234567890123456789012345678901234567890123456"
      Dim str As String = "Now is the time for all good men to come to the aid of their party."
      Dim start As Integer
      Dim at As Integer
      Dim count As Integer
      Dim [end] As Integer

      start = str.Length - 1
      [end] = start / 2 - 1
      Console.WriteLine("All occurrences of 'he' from position {0} to {1}.", start, [end])
      Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str)
      Console.Write("The string 'he' occurs at position(s): ")
      
      count = 0
      at = 0
      While start > - 1 And at > - 1
         count = start - [end] 'Count must be within the substring.
         at = str.LastIndexOf("he", start, count)
         If at > - 1 Then
            Console.Write("{0} ", at)
            start = at - 1
         End If
      End While
      Console.Write("{0}{0}{0}", Environment.NewLine)
   End Sub 'Main 
End Class 'Sample
'
'This example produces the following results:
'All occurrences of 'he' from position 66 to 32.
'0----+----1----+----2----+----3----+----4----+----5----+----6----+-
'0123456789012345678901234567890123456789012345678901234567890123456
'Now is the time for all good men to come to the aid of their party.
'
'The string 'he' occurs at position(s): 56 45
'
'

[C#] 
// Sample for String.LastIndexOf(String, Int32, Int32)
using System;

class Sample {
    public static void Main() {

    string br1 = "0----+----1----+----2----+----3----+----4----+----5----+----6----+-";
    string br2 = "0123456789012345678901234567890123456789012345678901234567890123456";
    string str = "Now is the time for all good men to come to the aid of their party.";
    int start;
    int at;
    int count;
    int end;

    start = str.Length-1;
    end = start/2 - 1;
    Console.WriteLine("All occurrences of 'he' from position {0} to {1}.", start, end);
    Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str);
    Console.Write("The string 'he' occurs at position(s): ");

    count = 0;
    at = 0;
    while((start > -1) && (at > -1))
        {
        count = start - end; //Count must be within the substring.
        at = str.LastIndexOf("he", start, count);
        if (at > -1) 
            {
            Console.Write("{0} ", at);
            start = at - 1;
            }
        }
    Console.Write("{0}{0}{0}", Environment.NewLine);
    }
}
/*
This example produces the following results:
All occurrences of 'he' from position 66 to 32.
0----+----1----+----2----+----3----+----4----+----5----+----6----+-
0123456789012345678901234567890123456789012345678901234567890123456
Now is the time for all good men to come to the aid of their party.

The string 'he' occurs at position(s): 56 45
*/

[C++] 
// Sample for String::LastIndexOf(String, Int32, Int32)
#using <mscorlib.dll>

using namespace System;

int main()
{
    String* br1 = S"0----+----1----+----2----+----3----+----4----+----5----+----6----+-";
    String* br2 = S"0123456789012345678901234567890123456789012345678901234567890123456";
    String* str = S"Now is the time for all good men to come to the aid of their party.";
    int start;
    int at;
    int count;
    int end;

    start = str->Length-1;
    end = start/2 - 1;
    Console::WriteLine(S"All occurrences of 'he' from position {0} to {1}.", __box(start), __box(end));
    Console::WriteLine(S"{1}{0}{2}{0}{3}{0}", Environment::NewLine, br1, br2, str);
    Console::Write(S"The string 'he' occurs at position(s): ");

    count = 0;
    at = 0;
    while((start > -1) && (at > -1)) {
        count = start - end; //Count must be within the substring.
        at = str->LastIndexOf(S"he", start, count);
        if (at > -1) {
            Console::Write(S"{0} ", __box(at));
            start = at - 1;
        }
    }
    Console::Write(S"{0} {0} {0}", Environment::NewLine);
}
/*
This example produces the following results:
All occurrences of 'he' from position 66 to 32.
0----+----1----+----2----+----3----+----4----+----5----+----6----+-
0123456789012345678901234567890123456789012345678901234567890123456
Now is the time for all good men to come to the aid of their party.

The string 'he' occurs at position(s): 56 45
*/

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework, Common Language Infrastructure (CLI) Standard

See Also

String Class | String Members | System Namespace | String.LastIndexOf Overload List | Int32 | IndexOf | IndexOfAny | LastIndexOfAny

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