Storing dates, which structure? c#

Question

Say I have a list of 1000 random dates, call it L

I dont think c# has a 'Tree' collection, so Im wondering how to implement the following:

The tree will be 3 stages deep, the first stage contains the year, the next stage contains all months in L in the parent year, and the final stage contains all days in the 'parent' month, and 'grandparent' year.

What sort of collection should I use, or I could just use a nested array?

Answer 1

How about

Dictionary<int, Dictionary<int, HashSet<int>>> dateTree;

But really, with out knowing how you need to use it, we can't reall help. Can you give us more information on why you want to store dates this way?

Answer 2

I've not tested the code, but you should be able to do something like this:

class Container
{
    public Container() { Items = new Dictionary<int, Container>(); }
    public DateTime DateTime {get;set;}
    Dictionary<int, Container> Items {get;set;}
}

Dictionary<int, Container> items = new Dictionary<int, Container>();

foreach (var date in theListCalledL)
{
    Container yearContainer;
    if (!items.TryGetValue(date.Year, out yearContainer))
    {
        yearContainer = new Contanier{DateTime = date};
        items.Add(date.Year, yearContainer);
    }

    Container monthContainer;
    if (!yearContainer.Items.TryGetValue(date.Month, out monthContainer))
    {
        monthContainer = new Contanier{DateTime = date};
        yearContainer.Add(date.Month, monthContainer);
    }

    Container dayContainer;
    if (!monthContainer.Items.TryGetValue(date.Day, out dayContainer))
    {
        dayContainer = new Contanier{DateTime = date};
        monthContainer.Add(date.Day, dayContainer);
    }
}

//and to get items:
var container = items[1997][8][10];
Console.WriteLine("The date was: " + contanier.DateTime);

var tmp = items[1997];
Console.WriteLine("1997 has items for " + tmp.Items.Count + " months.");