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💡 C# Tip: Nested Loops vs SelectMany

✔ SelectMany is a powerful LINQ operator that can streamline your code when dealing with nested collections. Suppose you have a scenario where you have a list of departments, and each department has its own list of employees. You want to retrieve all employees in a single, flat list.

✅ Using Nested Loops: Traditionally, you’d flatten a nested collection using nested loops, which can lead to verbose code and potential readability issues as the level of nesting grows.

✅ Using SelectMany: SelectMany allows you to flatten these nested collections with ease, transforming a list of lists into one single list, resulting in cleaner, more concise code.

🔥 Example: Retrieving All Employees with Nested Loops Vs SelectMany

Scenario:

Imagine you have a List<Department> where each Department has a List<Employee>. You want to get a single, flat List<Employee> containing all employees across all departments.

Using Nested Loops

Using nested loops, we would iterate through each department and then through each employee in that department, adding them to a new list.

Using nested loops, we would iterate through each department and then through each employee in that department, adding them to a new list.

Output: The allEmployees list now contains all employees across both departments.

With SelectMany, we can achieve the same result in a single line by flattening the collection:

SelectMany takes each List<Employee> in departments, extracts its employees, and flattens them into a single List<Employee>.

💡 Key Points:

  • Conciseness: Eliminates the need for nested loops.
  • Improved Readability: Makes the flattening process more intuitive.
  • Functional Approach: Fits well in LINQ-based, functional code style, especially when working with complex collections.

🤔 Have you used SelectMany in your projects before?

Thank you for reading! 📖