How to store duplicate data from xml file in C#

Question

I'm having an xml file like

<Root>
 <Child val1="1" Val2="0"/>
 <Child val1="1" Val2="2"/>
 <Child val1="1" Val2="3"/>
 <Child val1="1" Val2="4"/>
 <Child val1="1" Val2="5"/>
 <Child val1="6" Val2="0"/>
 <Child val1="7" Val2="0"/>
</Root>

i need to store the data in any temporary storage ( namely a Dictionary) for some sort of manipulations . but i cannot use dictionary here because dictionary does not support same keys. can any one suggest me a better way to store this data?

Answer 1

you can still use a dictionary for the val1 values, just have the second value be a list of values instead of just a list. then simply check if the DataKey exists, if it does do a list.Add(val2)

Answer 2

Well, you could use a Dictionary<int, List<int>> - or for storage only (no changes) you could use LINQ's ToLookup method which will build a multi-valued map for you very easily. Something like (using LINQ to XML):

var lookup = doc.Descendants("Child")
                .ToLookup(x => (int) x.Attribute("val1"),
                          x => (int) x.Attribute("val2"));

// Will iterate 5 times, printing 0, 2, 3, 4, 5 
foreach (var value in lookup[1])
{
    Console.WriteLine(value); 
}

EDIT: To display all the information, you'd do something like:

foreach (var grouping in lookup)
{
    foreach (var value in grouping)
    {
        Console.WriteLine("{0} {1}", grouping.Key, value);
    }
}

Answer 3

If .NET 4.0 you can use a Tuple<int, int> and List<Tuple<int, int>> if data is not key-value pairs

Answer 4

In this case you can just create a struct Child with two fields val1 and val2. Then you can use a List of Child to store this data.
If you need some sorting or equality issues or your xml is more complex than example you might need to use Dictionary or HashTable of Lists.