How to Use Substring in C# : A Simple Example

The Substring method in C# is an essential tool for extracting parts of a string. Whether you’re working with user input, parsing data, or formatting output, Substring can help you isolate specific sections of a string quickly and easily. In this blog post, we’ll explore how Substring works with a basic example.

Syntax of Substring

The Substring method has two main overloads:

string result = originalString.Substring(startIndex);
string result = originalString.Substring(startIndex, length);

• startIndex: The position where the substring starts (0-based index).
• length (optional): The number of characters to extract from the starting index.

Example 1: Extracting a Simple Substring

Let’s say you have a simple string and want to extract a portion of it using Substring.

using System;

class Program
{
    static void Main()
    {
        string text = "Hello, World!";
        
        // Extract a substring starting at index 7
        string result = text.Substring(7);
        
        Console.WriteLine(result);  // Output: "World!"
    }
}

Explanation:

• In this example, "Hello, World!" is the original string.
• We use Substring(7), which starts at index 7 and extracts all characters from that point onward.
• The output will be "World!".

Example 2: Extracting a Fixed Number of Characters

You can also specify the number of characters to extract. This is useful when you only need a specific portion of the string.

using System;

class Program
{
    static void Main()
    {
        string text = "Hello, World!";
        
        // Extract 5 characters starting at index 7
        string result = text.Substring(7, 5);
        
        Console.WriteLine(result);  // Output: "World"
    }
}

Explanation:

• Here, we use Substring(7, 5), which starts at index 7 and extracts 5 characters.
• This gives us "World" as the output.

Example 3: Using Substring with Dynamic Input

You can also use Substring with user input or dynamically created strings, which can be useful for parsing specific parts of user-provided data.

using System;

class Program
{
    static void Main()
    {
        Console.WriteLine("Enter a phrase:");
        string input = Console.ReadLine();
        
        // Extract the first 5 characters, if input is long enough
        if (input.Length >= 5)
        {
            string result = input.Substring(0, 5);
            Console.WriteLine("First 5 characters: " + result);
        }
        else
        {
            Console.WriteLine("Input is too short.");
        }
    }
}

Explanation:

• We take user input and use Substring(0, 5) to get the first 5 characters.
• We also check if the input is at least 5 characters long before using Substring, avoiding errors.

Summary

The Substring method in C# is a versatile tool for extracting parts of a string:

• Substring(startIndex): Extracts from the start index to the end of the string.
• Substring(startIndex, length): Extracts a specified number of characters starting from the start index.

With these basics, you can easily extract and work with specific sections of text in your C# projects. Try it out and see how Substring can help you streamline string manipulation!

Happy Coding…

Subscribe to Youtube Channel