LINQ：C＃中XML节点的总和

Question

I have an XML document and I would like to sum all elements of a specific name. How do I do this?

Answer 1

You can start with the following code, which sums the value of specificName elements anywhere in the document ( Descendants returns a collection of all elements with the specified name, regardless how deeply nested they are):

var doc = XDocument.Load("doc.xml");
var sum = (from nd in doc.Descendants("specificName")
           select Int32.Parse(nd.Value)).Sum();

Alternatively, if you don't want to use the query syntax, you could write something like:

var sum = doc.Descendants("specificName").Sum(nd => 
            Int32.Parse(nd.Value));

The examples assume that the value is stored as a text inside the element and that it is an integer.

Answer 2

Suppose this is your XML:

<nodes>
     <reading c='1'>17</reading>
     <reading c='2'>18</reading>
     <reading c='3'>19</reading>
     <reading c='4'>21</reading>
     <reading c='5'>4</reading>
     <reading c='6'>3</reading>
     <reading c='7'>7</reading>
</nodes>

Then use this code to sum the values of the reading elements:

public void Run()
{
    XDocument doc = XDocument.Load(fileToLoad);
    System.Console.WriteLine("\nSumming:");
    var sum = doc.Element("nodes")
                 .Elements("reading")
                 .Sum(n => int.Parse(n.Value));

    Console.WriteLine("  {0}", sum);
}