String.LastIndexOfAny Method (Char[], Int32)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
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.
Assembly: mscorlib (in mscorlib.dll)
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.
Return Value
Type: System.Int32The index position of the last occurrence in this instance where any character in anyOf was found; otherwise, -1 if no character in anyOf was found or if the current instance equals String.Empty.
| Exception | Condition |
|---|---|
| ArgumentNullException | anyOf is null. |
| ArgumentOutOfRangeException | The current instance does not equal String.Empty and startIndex specifies a position 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 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 example finds the index of the last occurrence of any character in the string "is" within a substring of another string.
// Sample for String.LastIndexOfAny(Char[], Int32) using System; class Example { public static void Demo(System.Windows.Controls.TextBlock outputBlock) { 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 - 1) / 2; outputBlock.Text += String.Format("The last character occurrence from position {0} to 0.", start) + "\n"; outputBlock.Text += String.Format("{1}{0}{2}{0}{3}{0}", Environment.NewLine, br1, br2, str) + "\n"; outputBlock.Text += String.Format("A character in '{0}' occurs at position: ", target); at = str.LastIndexOfAny(anyOf, start); if (at > -1) outputBlock.Text += at; else outputBlock.Text += "(not found)"; outputBlock.Text += String.Format("{0}{0}{0}", Environment.NewLine); } } /* This example produces the following results: The last character occurrence from position 33 to 0. 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: 12 */