Pattern Matching In C#: An Explanation Using Examples

Pattern Matching in C# is a powerful feature introduced in recent versions of C#. Moreover, It enables programmers to produce code that is clearer and more concise.

Logic is readable because to this feature. It makes conditional statements like switch and if simpler. Therefore, This makes it easier to maintain code.

It has improved with each successive version of C#. More power and flexibility have been added with C# 8.0, 9.0, and .NET 6.

Why Use Pattern Matching in C#?

In C#, It aids in avoiding lengthy and disorganized if-else chains. Not only does it provide cleaner syntax, but it also improves performance.

In many cases, developers use it instead of type casting. This approach also helps minimize code duplication.

Pattern matching, for example, makes it possible to simultaneously examine object types and values. This facilitates the understanding of code.

Pattern Matching Types in C#

Let us examine the various pattern matching formats that are offered by current C# versions.

1. Type Pattern

This pattern checks if an object is of a specific type.

if (obj is string text)
{
    Console.WriteLine($"It's a string: {text}");
}

Here, obj is tested. If it’s a string, it’s assigned to text.

2. Switch Expression

Switch expressions are a concise alternative to switch statements.

string result = shape switch
{
    Circle c => $"Circle with radius {c.Radius}",
    Square s => $"Square with side {s.Side}",
    _ => "Unknown shape"
};

These expressions are easy to read and extend.

3. Relational Pattern

Relational patterns allow comparison using logical operators.

string grade = score switch
{
    >= 90 => "A",
    >= 80 => "B",
    >= 70 => "C",
    _ => "F"
};

This pattern is especially useful in grading or range-based scenarios.

4. Logical Pattern

You can combine patterns using logical operators like and, or, and not.

if (number is >= 1 and <= 100)
{
    Console.WriteLine("Number is within range.");
}

This makes your conditions both powerful and readable.

5. Property Pattern

This pattern checks specific properties within objects.

if (person is { Age: >= 18, Name: not null })
{
    Console.WriteLine($"{person.Name} is an adult.");
}

Property patterns are ideal for complex data structures.

6. Positional Pattern

Use this with deconstructed types or tuples.

if (point is (0, 0))
{
    Console.WriteLine("Point is at the origin.");
}

This is available from C# 9.0 onward.

Real-World Example of Pattern Matching in C#

public string GetAccountType(Account acc) =>
    acc switch
    {
        SavingsAccount => "Savings",
        CurrentAccount => "Current",
        FixedDepositAccount => "FD",
        _ => "Unknown"
    };

Benefits of Pattern Matching

• Improves readability
• Minimizes the duplication of code
• Removes needless casting
• Improves performance
• Promotes the use of declarative coding.

Because of these advantages, it is an essential C# feature.

When to Apply Pattern Matching

Make use of it when working with:

• APIs that return a variety of object types.
• Conditional logic that is complex.
• Deconstructed values or tuples.
• Matching deeply nested data structures.

For that reason, pattern matching is perfect for cleaning up switch-heavy logic.

For clean, modern C# development, Pattern Matching is revolutionary. It makes the code clearer and less complicated.

It continues to evolve in every C# release. So, to stay productive and future-proof your C# skills, learn it now.

Your codebase will appreciate it if you use it wisely.