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Get maximum amount of recurrences from XML using LINQ

开发者 https://www.devze.com 2022-12-17 02:58 出处:网络
I have a开发者_如何学Cn xml file containing basic information about products, with the following structure:

I have a开发者_如何学Cn xml file containing basic information about products, with the following structure:

 - products
   - Id 
   - Price
   - ManufacturerId

And another one, containing data about manufacturers:

 - manufacturers
   - Id
   - Name

I'd like to get the top 3 manufacturers with the most products (manufacturer name and number of products) from the products.xml file using LINQ.

Edit: the products.xml file looks like this:

<products>
  <row Id="1" Price="1.00" ManufacturerId="3"/>
  <row Id="1" Price="0.99" ManufacturerId="2"/>
</products>

The fields are attributes for both the products and manufacturers files.


Well, you can find out which manufacturers are the top ones without looking at who they are. You can then get the details in a second query.

It would help if you would show some sample XML - we don't know whether the manufacturer ID is in an attribute or an element, for example. But it would be something like:

var top3Ids = products.Elements("row")
                      .GroupBy(x => (string) x.Attribute("ManufacturerId"))
                      .Select(group => new { Id = group.Key,
                                             Count = group.Count() })
                      .OrderByDescending(x => x.Count)
                      .Select(x => x.Id)
                      .Take(3)
                      .ToList();

var top3 = from element in manufacturers.Elements("row")
           where top3Ids.Contains((string) element.Attribute("Id"))
           select (string) element.Attribute("Name");
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