如何获取多个类别的关键字匹配数？

Question

如何获取多个类别的关键字匹配数？

场景是，当我输入一个产品关键字时，我想得到很多类别中的匹配项号。

例如，当我输入关键字“iphone”时，页面会在很多类别中显示匹配的项目编号：

Mobile(5)
battery(2)
app(6)
typeA(2)
typeB(9)
typeC(15)
typeC(1)
typeD(9)
typeE(7)
typeF(8)
......
......
typeZ(5)



public class Product
{
    public int ProductId { get; set; }
    public string ProductName { get; set; }
}

public class Type
{
    public int TypeId { get; set; }
    public string TypeName { get; set; }
}

public class ProductType
{
    public int ProductId { get; set; }
    public int TypeId { get; set; }
}

/// <summary>
/// Test Data
/// </summary>
public class TestData
{
    public List<Product> GetProductList()
    {
        var list = new List<Product>(){
             new Product(){ ProductId=1, ProductName = "iphone1"},
             new Product(){ ProductId=2, ProductName = "iphone2"},
             new Product(){ ProductId=3, ProductName = "iphone3"},
             new Product(){ ProductId=4, ProductName = "ipad1"},
             new Product(){ ProductId=5, ProductName = "ipad2"},
             new Product(){ ProductId=6, ProductName = "mobile1"},
             new Product(){ ProductId=7, ProductName = "mobile2"},
             new Product(){ ProductId=8, ProductName = "cpu1"},
             new Product(){ ProductId=9, ProductName = "cpu2"},
             new Product(){ ProductId=10, ProductName = "cpu3"}
            };
        return list;
    }

    public List<Type> GetTypeList()
    {
        var list = new List<Type>(){
             new Type(){ TypeId=1, TypeName = "type1"},
             new Type(){ TypeId=2, TypeName = "type2"},
             new Type(){ TypeId=3, TypeName = "type3"},
             new Type(){ TypeId=4, TypeName = "type4"},
             new Type(){ TypeId=5, TypeName = "type5"}         
            };
        return list;
    }

    public List<ProductType> GetProductTypeList()
    {
        var list = new List<ProductType>(){
             new ProductType(){ ProductId=1, TypeId=1},
             new ProductType(){ ProductId=1, TypeId=2},
             new ProductType(){ ProductId=2, TypeId=1},
             new ProductType(){ ProductId=2, TypeId=3},
             new ProductType(){ ProductId=2, TypeId=4},
             new ProductType(){ ProductId=3, TypeId=2},
             new ProductType(){ ProductId=3, TypeId=5},
             new ProductType(){ ProductId=4, TypeId=2},
             new ProductType(){ ProductId=4, TypeId=3},
             new ProductType(){ ProductId=4, TypeId=5},
             new ProductType(){ ProductId=5, TypeId=2},
             new ProductType(){ ProductId=5, TypeId=4},
             new ProductType(){ ProductId=6, TypeId=1},
             new ProductType(){ ProductId=6, TypeId=2},
             new ProductType(){ ProductId=7, TypeId=2},
             new ProductType(){ ProductId=7, TypeId=5},
             new ProductType(){ ProductId=8, TypeId=2},
             new ProductType(){ ProductId=9, TypeId=3},
             new ProductType(){ ProductId=10, TypeId=2}
            };
        return list;
    }

如何实现这一点以获得更好的性能？

我使用 C# ASP.NET。

Answer 1

您可以使用 LINQ 执行此操作 - 现在不是很干净，但它可以为您提供一个列表 TypeMatches，其中包含类型名称和该类型的匹配数。

TestData testData = new TestData();
string keyword = "iphone";
var ProductListMatches = testData.GetProductList().Where(p => p.ProductName.Contains(keyword)).ToList();

var ProductTypeMatches = (from product in ProductListMatches
                            join productType in testData.GetProductTypeList() 
                            on product.ProductId equals productType.ProductId
                            select productType).ToList();

var TypeMatches = (from productTypeMatch in ProductTypeMatches
                    join pType in testData.GetTypeList()
                        on productTypeMatch.TypeId equals pType.TypeId
                    select pType).GroupBy(p => p.TypeId)
                    .Select(g => new { TypeName =  g.First().TypeName, Count = g.Count() })
                    .ToList();

Answer 2

如果你有一个

public class Item {
    public string Name;
    public string Keyword;
    public int Num;
}

和

List<Item> items = new List<Item>();

然后

var items2 = items.ToLookup(p => p.Keyword);

您可以像这样搜索关键字：

foreach (var item in items2[Keyword]) {
}

但也许您想要的不仅仅是每个项目的关键字......

 public class Item
 {
     public string Name;
     public List<string> Keywords = new List<string>();
     public int Num;
 }

 List<Item> items = new List<Item>();
 var items2 = items.SelectMany(p => p.Keywords.Select(q => new { Keyword = q, Item = p })).ToLookup(p => p.Keyword, p => p.Item);

和以前一样使用。

除非你想在 SQL 上做 :-)