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String.LastIndexOf Method (Char)

Reports the index position of the last occurrence of a specified Unicode character within this instance.

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

public int LastIndexOf (
	char value
)
public int LastIndexOf (
	char value
)
public function LastIndexOf (
	value : char
) : int

Parameters

value

A Unicode character to seek.

Return Value

The index position of value if that character is found, or -1 if it is not.

Exception typeCondition

ArgumentNullException

value is a null reference (Nothing in Visual Basic).

Index numbering starts from zero.

This method begins searching at the last character position of this instance and proceeds backwards towards the beginning until either value is found or the first character position has been examined. The search is case-sensitive.

This method performs an ordinal (culture-insensitive) search, where a character is considered equivalent to another character only if their Unicode scalar values are the same. To perform a culture-sensitive search, use the CompareInfo.LastIndexOf method, where a Unicode scalar value representing a precomposed character, such as the ligature 'Æ' (U+00C6), might be considered equivalent to any occurrence of the character's components in the correct sequence, such as "AE" (U+0041, U+0045), depending on the culture.

The following code example demonstrates how you can search a String for a character using the LastIndexOf method.

// Create a Unicode String with 5 Greek Alpha characters
String szGreekAlpha = new String('\u0319',5);
// Create a Unicode String with a Greek Omega character
String szGreekOmega = new String(new char [] {'\u03A9','\u03A9','\u03A9'},2,1);

String szGreekLetters = String.Concat(szGreekOmega, szGreekAlpha, szGreekOmega.Clone());

// Examine the result
Console.WriteLine(szGreekLetters);

// The first index of Alpha
int ialpha = szGreekLetters.IndexOf('\u0319');
// The last index of Omega
int iomega = szGreekLetters.LastIndexOf('\u03A9');

Console.WriteLine("The Greek letter Alpha first appears at index " + ialpha +
    " and Omega last appears at index " + iomega + " in this String.");

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

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