C# String Interpolation

Welcome to another tutorial at The Coding College! Today, we’ll cover C# String Interpolation, a modern, clean, and efficient way to embed variables directly into strings.

Mastering string interpolation will improve your code readability and make string handling more enjoyable.

For more tutorials on C# and programming, visit thecodingcollege.com.

What is String Interpolation in C#?

String Interpolation in C# allows you to insert variables, expressions, or even method calls directly into a string.

It is denoted by the $ symbol placed before the string and uses curly braces {} to embed values.

Syntax of String Interpolation

string result = $"Text {variable}";

• $: Indicates string interpolation.
• {}: Placeholders to insert variables or expressions.

Example 1: Simple String Interpolation

Here is a basic example to display a full name using string interpolation:

using System;

class Program
{
    static void Main()
    {
        string firstName = "John";
        string lastName = "Doe";

        // Using string interpolation
        string fullName = $"Full Name: {firstName} {lastName}";

        Console.WriteLine(fullName);
    }
}

Output:

Full Name: John Doe

Example 2: Embedding Expressions

String interpolation allows you to include expressions like calculations directly inside the string.

using System;

class Program
{
    static void Main()
    {
        int a = 10;
        int b = 20;

        // Performing calculations inside the interpolated string
        string result = $"The sum of {a} and {b} is {a + b}.";

        Console.WriteLine(result);
    }
}

Output:

The sum of 10 and 20 is 30.

Example 3: Formatting Dates and Numbers

You can format dates and numbers within an interpolated string.

using System;

class Program
{
    static void Main()
    {
        DateTime today = DateTime.Now;
        double price = 199.99;

        // Formatting date and number
        string message = $"Today's date is {today:MMMM dd, yyyy} and the price is {price:C}.";

        Console.WriteLine(message);
    }
}

Output:

Today's date is March 14, 2024 and the price is $199.99.

• {today:MMMM dd, yyyy}: Formats the date to a readable format.
• {price:C}: Displays the price as currency.

Example 4: Combining Strings and Methods

You can even call methods directly within the string interpolation.

using System;

class Program
{
    static void Main()
    {
        string name = "The Coding College";

        // Using string interpolation with methods
        string upperCase = $"Welcome to {name.ToUpper()}!";

        Console.WriteLine(upperCase);
    }
}

Output:

Welcome to THE CODING COLLEGE!

Advantages of String Interpolation

1. Improved Readability: Makes code cleaner and easier to understand.
2. Reduced Errors: Avoids manual string concatenation mistakes.
3. Inline Expressions: You can perform calculations or call methods directly.
4. No Placeholder Confusion: Unlike String.Format, there’s no need to match index positions.

String Interpolation vs String.Format

Example 5: Multiline Interpolated Strings

You can use string interpolation with multi-line strings using verbatim strings (@).

using System;

class Program
{
    static void Main()
    {
        string title = "C# String Interpolation";
        string author = "The Coding College";

        string message = $@"
        ============================
        Title: {title}
        Author: {author}
        Date: {DateTime.Now:MMMM dd, yyyy}
        ============================";

        Console.WriteLine(message);
    }
}

Output:

============================
Title: C# String Interpolation
Author: The Coding College
Date: March 14, 2024
============================

When to Use String Interpolation?

Use string interpolation:

1. For cleaner and concise string formatting.
2. When embedding variables or expressions directly into strings.
3. For dynamic or real-time string generation.

Conclusion

String interpolation is a powerful feature in C# that simplifies string formatting and improves code readability.

Instead of juggling multiple concatenations or managing placeholder indexes, you can write cleaner, more modern code using the $ syntax.

For more C# tutorials and coding resources, visit The Coding College—your go-to destination for programming knowledge!