LastIndexOf Method (Char, Int32)

String.LastIndexOf Method (Char, Int32)


Reports the zero-based index position of the last occurrence of a specified Unicode character within this instance. The search starts at a specified character position and proceeds backward toward the beginning of the string.

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

public int LastIndexOf(
	char value,
	int startIndex


Type: System.Char

The Unicode character to seek.

Type: System.Int32

The starting position of the search.The search proceeds from startIndex toward the beginning of this instance.

Return Value

Type: System.Int32

The zero-based index position of value if that character is found, or -1 if it is not foundor if the current instance equals String.Empty.

Exception Condition

The current instance does not equal String.Empty, and startIndex is less than zero or greater than or equal to the length of this instance.

Index numbering starts from zero. That is, the first character in the string is at index zero and the last is at Length - 1.This method begins searching at the startIndex character position of this instance and proceeds backward toward the beginning of the current instance until either value is found or the first character position has been examined. For example, if startIndex is Length - 1, the method searches every character from the last character in the string to the beginning. 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 all occurrences of a character in a string, working from the end of the string to the start of the string.

// Sample for String.Join(String, String[], int int)
using System;

class Sample {
    public static void Main() {
    String[] val = {"apple", "orange", "grape", "pear"};
    String sep   = ", ";
    String result;

    Console.WriteLine("sep = '{0}'", sep);
    Console.WriteLine("val[] = {{'{0}' '{1}' '{2}' '{3}'}}", val[0], val[1], val[2], val[3]);
    result = String.Join(sep, val, 1, 2);
    Console.WriteLine("String.Join(sep, val, 1, 2) = '{0}'", result);
This example produces the following results:
sep = ', '
val[] = {'apple' 'orange' 'grape' 'pear'}
String.Join(sep, val, 1, 2) = 'orange, grape'

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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