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String.IndexOfAny Method (Char[], Int32)

Reports the index of the first occurrence in this instance of any character in a specified array of Unicode characters. The search starts at a specified character position.

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

public int IndexOfAny(
	char[] anyOf,
	int startIndex
)

Parameters

anyOf
Type: System.Char[]

A Unicode character array containing one or more characters to seek.

startIndex
Type: System.Int32

The search starting position.

Return Value

Type: System.Int32
The zero-based index position of the first occurrence in this instance where any character in anyOf was found; otherwise, -1 if no character in anyOf was found.

ExceptionCondition
ArgumentNullException

anyOf is null.

ArgumentOutOfRangeException

startIndex is negative.

-or-

startIndex is greater than the number of characters in this instance.

Index numbering starts from 0 (zero). The startIndex parameter can range from 0 to one less than the length of the string instance.

The search ranges from startIndex to the end of the string.

The search for anyOf 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 value are the same. To perform a culture-sensitive search, use the CompareInfo.IndexOf 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 occurrence of any character of the string "is" within a substring of another string.

// Sample for String.IndexOfAny(Char[], 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;
    string target = "is";
    char[] anyOf = target.ToCharArray();

    start = str.Length/2;
    Console.WriteLine();
    Console.WriteLine("The first character occurrence from position {0} to {1}.", 
                           start, str.Length-1);
    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.IndexOfAny(anyOf, start);
    if (at > -1) 
        Console.Write(at);
    else
        Console.Write("(not found)");
    Console.WriteLine();
    }
}
/*

The first character occurrence from position 33 to 66.
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 'is' occurs at position: 49

*/

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

Date

History

Reason

Noted that an exception is not thrown for an empty string if the index parameter is invalid.

Content bug fix.

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