C# String Substring()

using System;
namespace CsharpString
{
    class Test
    {
        public static void Main(string[] args)
        {
            string text = "C# is fun";

            // Returns substring of length 3 from index 6 
            Console.WriteLine(text.Substring(6, 3));

            Console.ReadLine();

        }
    }
} 

// Output: fun

Substring() Syntax

The syntax of the string Substring() method is:

Substring(int startIndex, int length)

Here, Substring() is a method of class String.

Substring() Parameters

The Substring() method takes the following parameters:

• startIndex - the beginning index of the substring
• length - (optional) - length of the substring

Substring() Return Value

The Substring() method returns a substring from the given string.

Example 1: C# Substring() Without Length

using System;
namespace CsharpString
{
    class Test
    {
        public static void Main(string[] args)
        {
            string text = "Programiz";

            // Returns substring from the second character 
            string result = text.Substring(1);

            Console.WriteLine(result);
            Console.ReadLine();
        }
    }
}

Output

rogramiz

Notice this line in the above example:

string result = text.Substring(1);

The code text.Substring(1) returns the substring from the second character of "Programiz".

Example 2: C# Substring() With Length

using System;
namespace CsharpString
{
    class Test
    {
        public static void Main(string[] args)
        {
            string text = "Programiz is for programmers";

            // Returns substring of length 9 from the first character 
            string result = text.Substring(0, 9);

            Console.WriteLine(result);
            Console.ReadLine();
        }
    }
}

Output

Programiz

Notice this line in the above example:

string result = text.Substring(0, 9);

Here,

• 0 (the first character of text) is the beginning index of the substring
• 9 is the length of the substring

This gives us the substring "Programiz".

Example 3: C# Substring() Before Specific Character

using System;
namespace CsharpString
{
    class Test
    {
        public static void Main(string[] args)
        {
            string text = "C#. Programiz";

            // Returns substring from index 0 to index before '.' 
            string result = text.Substring(0, text.IndexOf('.'));

            Console.WriteLine(result);
            Console.ReadLine();
        }
    }
}

Output

C#

Here, text.IndexOf('.') gives the length of the substring, which is the index of '.'.