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🔍 Pattern Matching in C#
Pattern Matching is a feature in C# that allows you to test an object against a pattern and extract data from it in a concise and readable way. It simplifies conditional logic and enhances code clarity.
🧩 Types of Patterns
- Type Pattern: Checks if an object is of a specific type.
- Constant Pattern: Compares a value to a constant.
- Relational Pattern: Uses relational operators like >, <, ==.
- Property Pattern: Matches based on object properties.
- Positional Pattern: Matches deconstructed values or tuples.
- Var Pattern: Always matches and assigns the value to a variable.
💡 Example: Property Pattern
public class Person {
public string Name { get; set; }
public int Age { get; set; }
}
Person person = new Person { Name = "Alice", Age = 25 };
if (person is { Age: > 18 }) {
Console.WriteLine("Adult");
}
✅ Best Practices
- Use pattern matching to simplify type checks and null checks.
- Prefer
switch expressions for clean branching logic.
- Use property patterns to match nested object structures.
- Avoid overly complex patterns that reduce readability.
- Combine patterns with
is and switch for expressive logic.
📌 When to Use
- When checking types and extracting values in one step.
- For replacing verbose
if-else or switch statements.
- In data-driven logic where object shape matters.
- When working with tuples or deconstructed types.
🚫 When Not to Use
- In performance-critical code where pattern matching may introduce overhead.
- When logic becomes too nested or hard to read.
- For simple equality checks where traditional comparisons are clearer.
⚠️ Precautions
- Ensure patterns are exhaustive to avoid unexpected behavior.
- Be cautious with null values—use
is not null checks.
- Understand how reference vs value types behave in patterns.
- Test edge cases, especially with
switch expressions.
🎯 Advantages of Pattern Matching
- Concise syntax: Reduces boilerplate code.
- Improved readability: Expresses intent clearly.
- Safe type casting: Eliminates manual casting.
- Flexible logic: Supports complex matching scenarios.
- Modern design: Aligns with functional programming styles.
📝 Conclusion
Pattern Matching in C# is a powerful tool for writing expressive, readable, and safe code. Use it to simplify logic, reduce boilerplate, and enhance maintainability—especially when working with complex data structures.
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