C# String - LastIndexOf() Method

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The C# String LastIndexOf() method is used to return the index position of the last occurrence of a specified character or string within this string's object.

It's important to note that this method can be overloaded by passing different arguments to this method. We can use the overloaded method of LastIndexOf() in the examples below.

Syntax

Following is the syntax of the C# string LastIndexOf(Char) method −

public int LastIndexOf(char value);

Parameters

This method accepts a parameter that is a character or a string to search for.

Return value

This method returns a 32-bit signed integer representing the index position of the specified value if the character is found. If the character is not found, it returns -1.

Example 1: Using LastIndexOf(char value) Syntax

Following is the basic example of theLastIndexOf(char value)method to find the last index of character that is present in the string −

    
using System;
class Program {
   static void Main() {
      string str = "tutorialspoint";
      int indx = str.LastIndexOf('t');
      Console.Write("Last Index Value of character 't' is " + indx);
   }
}

Output

Following is the output −

Last Index Value of character 't' is 13

Example 2: Using LastIndexOf(string value) Syntax

Let us look at another example of the LastIndexOf(string value) method. Here, we use another version of the syntax to find the last index of specified string −

using System;
class Program {
   static void Main() {
      string str = "tutorialspoint point";
      int last_indx = str.LastIndexOf("point");
      Console.Write("Last Index Value of string 'point' is " + last_indx);
   }
}

Output

Following is the output −

Last Index Value of string 'point' is 15

Example 3: Using LastIndexOf(char value, int startIndex) Syntax

In this example, we use the LastIndexOf(char value, int startIndex) method to finds the last occurrence of a character starting from a specified index and searching backward −

using System;
class Program {
   static void Main(){
      string text = "Hello, world!";
      int index = text.LastIndexOf('o', 7);
      Console.WriteLine(index);
   }
}

Output

Following is the output −

4

Example 4: Using LastIndexOf(char value, int startIndex, int count) Syntax

In this example, we use the LastIndexOf(char value, int startIndex, int count) method to finds the last occurrence of a character within a specified range of characters −

using System; 
class Program {
   static void Main(){
      string text = "Hii tutorialspoint";
      int index = text.LastIndexOf('i', 12, 6);
      Console.WriteLine("Last occurrence of 'i' is " + index);
   }
}

Output

Following is the output −

Last occurrence of 'i' is 9