How would be the query for this XML file?

Question

I'm having a hard time trying to create the query. This is the file:

<Root>
<Summary>
    <Objective ID="1">
        <Exam Result="70" />
        <Exam Result="90" />
    </Objective>
    <Objective ID="2">
        <Exam Result="100" />
        <Exam Result="90" />
    </Objective>
</Summary>
</Root>

I need to get the values in List< List< double>>. The first list if for objectives, and the last one is to store each result.

Any doubt, please let me know

Answer 1

I suspect you want:

var results = doc.Descendants("Objective")
                 .Select(x => x.Elements("Exam")
                               .Select(exam => (double) exam.Attribute("Result"))
                               .ToList())
                 .ToList();

Or if the objective ID is important, you might want to consider a Dictionary<int, List<double>>:

var results = doc.Descendants("Objective")
                 .ToDictionary(x => (int) x.Attribute("ID"),
                               x => x.Elements("Exam")
                                     .Select(y => (double) y.Attribute("Result"))
                                     .ToList());

Or a Lookup<int, double>:

var results = doc.Descendants("Exam")
                 .ToLookup(x => (int) x.Parent.Attribute("ID"),
                           x => x.Select(y => (double) y.Attribute("Result"));