Determine index of a character in a string in C#

This post will discuss how to determine the index of a character in a string in C#.

The standard solution to find the position of a character in a string is using the String.IndexOf() method. It returns the index of the first occurrence of the specified character within the string, and returns -1 if the character is not found. The following example demonstrates its usage.

using System;

public class Example

{

public static void Main()

{

string input = "Hello, World";

char c = ',';

int index = input.IndexOf(c);

Console.WriteLine("Index of character '{0}' is {1}", c, index);

}

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Output:

Index of character ‘,’ is 5

Note that the IndexOf() method is overloaded for strings. Therefore, you can determine the index of the first occurrence of the specified string within your string.

using System;

public class Example

{

public static void Main()

{

string input = "Hello, World";

string s = "World";

int index = input.IndexOf(s);

Console.WriteLine("Index of substring \"{0}\" is {1}", s, index);

}

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Output:

Index of substring “World” is 7

If you need to find the position of the last occurrence of a character or string, consider using the String.LastIndexOf() method.

using System;

public class Example

{

public static void Main()

{

string input = "A,B,C";

char c = ',';

int lastIndex = input.LastIndexOf(c);

Console.WriteLine("The last index of character '{0}' is {1}", c, lastIndex);

}

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Output:

The last index of character ‘,’ is 3

That’s all about determining the index of a character in a string in C#.

Determine index of a character in a string in C#

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