String.LastIndexOfAny Method (Char(), Int32, Int32)

.NET Framework (current version)

Reports the zero-based index position of the last occurrence in this instance of one or more characters specified in a Unicode array. The search starts at a specified character position and proceeds backward toward the beginning of the string for a specified number of character positions.

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

Syntax

C++

Public Function LastIndexOfAny (
	anyOf As Char(),
	startIndex As Integer,
	count As Integer
) As Integer

Parameters

anyOf: Type: System.Char()
A Unicode character array containing one or more characters to seek.

startIndex: Type: System.Int32
The search starting position. The search proceeds from startIndex toward the beginning of this instance.

count: Type: System.Int32
The number of character positions to examine.

Return Value

Type: System.Int32

The index position of the last occurrence in this instance where any character in anyOf was found; -1 if no character in anyOf was found or if the current instance equals String.Empty.

Exceptions

Exception	Condition
ArgumentNullException	anyOf is null.
ArgumentOutOfRangeException	The current instance does not equal String.Empty, and count or startIndex is negative. -or- The current instance does not equal String.Empty, and startIndex minus count + 1 is less than zero.

Remarks

Index numbering starts from zero.

This method begins searching at the startIndex character position of this instance and proceeds backward toward the beginning until either a character in anyOf is found or count character positions have 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.

Examples

The following example finds the index of the last occurrence of any character in the string "aid" within a substring of another string.

C++

' Sample for String.LastIndexOfAny(Char[], 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 target As String = "aid"
      Dim anyOf As Char() = target.ToCharArray()

      start =(str.Length - 1) * 2 / 3
      count =(str.Length - 1) / 3
      Console.WriteLine("The last character occurrence from position {0} for {1} characters.", start, count)
      Console.WriteLine("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str)
      Console.Write("A character in '{0}' occurs at position: ", target)

      at = str.LastIndexOfAny(anyOf, start, count)
      If at > - 1 Then
         Console.Write(at)
      Else
         Console.Write("(not found)")
      End If
      Console.Write("{0}{0}{0}", Environment.NewLine)
   End Sub 'Main
End Class 'Sample
'
'This example produces the following results:
'The last character occurrence from position 44 for 22 characters.
'0----+----1----+----2----+----3----+----4----+----5----+----6----+-
'0123456789012345678901234567890123456789012345678901234567890123456
'Now is the time for all good men to come to the aid of their party.
'
'A character in 'aid' occurs at position: 27
'

Version Information

Universal Windows Platform
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1