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

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 examines a specified number of character positions.

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

public int LastIndexOfAny(
	char[] anyOf,
	int startIndex,
	int count
)

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.

ExceptionCondition
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 specifies a position that is not within this instance.

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.

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


// Sample for String.LastIndexOfAny(Char[], 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;
    string target = "aid";
    char[] anyOf = 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) 
        Console.Write(at);
    else
        Console.Write("(not found)");
    Console.Write("{0}{0}{0}", Environment.NewLine);
    }
}
/*
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
*/


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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