C# 10 - guide with LINQ Query Returning Unexpected Results after Simple GroupBy Operation
I'm maintaining legacy code that Can someone help me understand I'm working with an scenario with a LINQ query where I'm trying to group a list of objects and then select certain properties, but the output doesn't match my expectations. I'm using C# 10 and .NET 6. Here’s a snippet of my code: ```csharp public class Order { public int Id { get; set; } public string Customer { get; set; } public decimal Amount { get; set; } } var orders = new List<Order> { new Order { Id = 1, Customer = "Alice", Amount = 100 }, new Order { Id = 2, Customer = "Bob", Amount = 200 }, new Order { Id = 3, Customer = "Alice", Amount = 150 } }; var groupedOrders = orders.GroupBy(o => o.Customer) .Select(g => new { Customer = g.Key, TotalAmount = g.Sum(o => o.Amount) }); foreach (var group in groupedOrders) { Console.WriteLine($"Customer: {group.Customer}, Total Amount: {group.TotalAmount}"); } ``` When I run this code, I expect to see: ``` Customer: Alice, Total Amount: 250 Customer: Bob, Total Amount: 200 ``` However, I am consistently seeing the output: ``` Customer: Alice, Total Amount: 100 Customer: Bob, Total Amount: 200 ``` It's as if the grouping isn't considering all the amounts for Alice correctly. I've checked for any duplicate entries in my `orders` list, but they seem fine. I've even tried debugging with breakpoints, and it appears that the `Sum` function only considers the first entry for Alice. I also tried using `ToList()` after the `GroupBy` method, but that didn't change the output. Are there any specific LINQ behaviors or nuances that I might be overlooking with grouping in C# 10? Any ideas on how to resolve this scenario would be greatly appreciated! I'm working on a CLI tool that needs to handle this. What's the best practice here? This is part of a larger REST API I'm building. What's the best practice here? Has anyone else encountered this?