Really Don't Use FirstOrDefault in .NET?

Don't Use FirstOrDefault in .NET ?

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C# Performance of

Find() vs. FirstOrDefault()

https://youtu.be/sMD02dUghrg

C# Performance of

Find() vs. FirstOrDefault()

 

Find

•  Designed for collections with direct access by index or key (like arrays or lists implementing IList). It retrieves an element based on a specific condition.
• Use Case: When you have a collection of objects and want to retrieve an object based on a unique identifier.

List numbers = new List { 1, 2, 3, 4, 5 };

int result = numbers.Find(x => x > 3); 

 

FirstOrDefault Method

• Use Case: When you want to find the first item that meets a certain condition in a collection.
• Example: Suppose you have a list of employees and want to find the first employee in the "Sales" department.

var employeeList = new List<Employee>(); var salesEmployee = employeeList.FirstOrDefault(e => e.Department == "Sales");

 

Summary

• Find:
• Suitable for lists or arrays with direct index/key access.
• Efficient for retrieving an item by a specific identifier.
• Find based on primary key
• With out querying the Database
• FirstOrDefault:
• Works with LINQ and any IEnumerable.
• It always queries the database
• Ideal for getting the first item that matches a condition or a default if no matches exist.

Key Differences:

• FirstOrDefault:
• Runs through the IEnumerable interface, typically using a foreach loop, which adds overhead.
• List<T>.Find:
• Not part of LINQ; it likely uses a standard for loop directly on the internal array, making it faster and more efficient for searching.

In essence, Find is optimized for performance on lists, while FirstOrDefault provides more flexibility with IEnumerable.

 

Conclusion

Both List<T>.Find() and Enumerable.FirstOrDefault() are effective for searching elements in collections, each with its own advantages:

• Performance: List<T>.Find() is typically marginally faster when working with List<T> due to direct access and potential optimizations.
• Flexibility: FirstOrDefault() offers broader applicability across different collection types and integrates seamlessly with LINQ queries.
• Use Case Fit: Choose Find() for list-specific, performance-critical scenarios, and FirstOrDefault() for more general, LINQ-based operations.