Export (0) Print
Expand All

String.LastIndexOf Method (String, Int32, Int32)

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.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

public int LastIndexOf (
	string value,
	int startIndex,
	int count
)
public int LastIndexOf (
	String value, 
	int startIndex, 
	int count
)
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.

Exception typeCondition

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.

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.

The following code example finds the index of all occurrences of a string in substring, working from the end of the substring to the start of the substring.

// 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
*/

// Sample for String.LastIndexOf(String, Int32, Int32)
import System.*;

class Sample
{
    public static void main(String[] args)
    {
        String br1 = "0----+----1----+----2----+----3----+----4----+----5----+"
            + "----6----+-";
        String br2 = "01234567890123456789012345678901234567890123456789012345"
            + "67890123456";
        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.get_Length() - 1;
        end = start / 2 - 1;
        Console.WriteLine("All occurrences of 'he' from position {0} to {1}.",
            (Int32)start, (Int32)end);
        Console.Write("{1}{0}", Environment.get_NewLine(), br1);
        Console.Write("{1}{0}", Environment.get_NewLine(), br2);
        Console.WriteLine("{1}{0}", Environment.get_NewLine(), 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} ", (Int32)at);
                start = at - 1;
            }
        }
        Console.Write("{0}{0}{0}", Environment.get_NewLine());
    } //main
} //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
*/

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0

Community Additions

ADD
Show:
© 2014 Microsoft