C# Selection of Top 2 product details from each region
From the given Product List
List<Product> productList = new List<Product>();
productList.Add(new Product("P001", 34566.78M, "North"));
productList.Add(new Product("P004", 4566.78M, "East"));
productList.Add(new Product("P007", 14566.78M, "South"));
productList.Add(new Product("P010", 2456.178M, "South"));
productList.Add(new Product("P011", 341566.78M, "North"));
productList.Add(new Product("P006", 64566.878M, "East"));
productList.Add(new Product("P00188", 664566.78M, "East"));
productList.Add(new Product("P00111", 3444566.78M, "Nort开发者_StackOverflowh"));
productList.Add(new Product("P00134", 3234566.78M, "South"));
How to select Top 2 Product (price based) from each region ?
I have written something like
var query = productList.OrderByDescending(p => p.ProductPrice).
Take(2).GroupBy(r => r.Region);
Group by region first, then within each group do the OrderBy/Take. For example:
var query = productList
.GroupBy(r => r.Region)
.Select(group => new { Region = group.Key,
Orders = group.OrderByDescending(p => p.ProductPrice)
.Take(2) });
It's not pretty and not terribly readable, but if you must do it in one statement, this will do the trick for you,
var q = productList.Select(pl => pl.Region)
.Distinct()
.ToList()
.SelectMany(region => productList.Where(pl => pl.Region == region)
.OrderByDescending(pl => pl.ProductPrice)
.Take(2));
I'd recommend breaking it up for readability though.
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