Sum - Grouped

Query

public void Linq80()
{
    List products = GetProductList();
  
    var categories =
        from p in products
        group p by p.Category into g
        select new { Category = g.Key, TotalUnitsInStock = g.Sum(p => p.UnitsInStock) };
  
    ObjectDumper.Write(categories);
}

Lambda Expression

public void Linq80()
{
    List products = GetProductList();
 
    var categories = products.GroupBy(prod => prod.Category).
        Select(prodGroup => new {Category = prodGroup.Key, TotalUnitsInStock = prodGroup.Sum(p => p.UnitsInStock)});
 
    ObjectDumper.Write(categories);
}

Output

Category=Beverages TotalUnitsInStock=559
Category=Condiments TotalUnitsInStock=507
Category=Produce TotalUnitsInStock=100
Category=Meat/Poultry TotalUnitsInStock=165
Category=Seafood TotalUnitsInStock=701
Category=Dairy Products TotalUnitsInStock=393
Category=Confections TotalUnitsInStock=386
Category=Grains/Cereals TotalUnitsInStock=308