Question

我正在尝试使用查询语法来遍历对象列表，并选择其UnitPrice属性的int最低的对象。

var lowPrice = from l in DataLoader.LoadProducts()
               group l by l.Category into newGroup
               select new
               {
                    cat = newGroup.Key,
                    lowest = from p in newGroup
                             where p.UnitPrice < p.UnitPrice
                             select p
               };

上面的代码应在UnitPrice属性中选择一个值最低的对象并将其存储到最低属性中。

但是我不知道选择单价最低的对象的正确语法。

这是我的产品对象的示例。有很多同类产品。我的目标是显示类别名称和该类别下单价最低的产品。我相信总共有6个类别。

new Product
                        {
                            ProductID = 1,
                            ProductName = "Chai",
                            Category = "Beverages",
                            UnitPrice = 18.0000M,
                            UnitsInStock = 39
                        },
                        new Product
                        {
                            ProductID = 2,
                            ProductName = "Chang",
                            Category = "Beverages",
                            UnitPrice = 19.0000M,
                            UnitsInStock = 17
                        },
                        new Product
                        {
                            ProductID = 3,
                            ProductName = "Aniseed Syrup",
                            Category = "Condiments",
                            UnitPrice = 10.0000M,
                            UnitsInStock = 13
                        },
                        new Product
                        {
                            ProductID = 4,
                            ProductName = "Chef Anton's Cajun Seasoning",
                            Category = "Condiments",
                            UnitPrice = 22.0000M,
                            UnitsInStock = 53
                        },

Answer 1

如果您要选择每个类别中价格最低的单个对象，请采用以下解决方案：

var lowestPriceCategories = DataLoader.LoadProducts()
    .GroupBy(x => x.Category)
    .Select(x => new
    {
        Category = x.Key,
        LowestPrice = x.OrderBy(y => y.UnitPrice).FirstOrDefault()
    });

Answer 2

感谢您的支持。我能够使用大家提出的建议创建自己认为需要的东西。

var lowPrice = from l in DataLoader.LoadProducts()
                           group l by l.Category into newGroup
                           select new
                           {
                               cat = newGroup.Key,
                               lowest = (from p in newGroup
                                         orderby p.UnitPrice
                                        select p).First()
                           };

结果

foreach (var p in lowPrice)
            {
                Console.WriteLine($"{p.cat} {p.lowest.ProductName}");
            }

如何选择具有最低属性linq查询语法的对象

2 个答案: