Question

I’m using entity framework and I’d like to store the total count of items within the bounds of a specific set of letters (if this makes sense):

A - D (12) - (where 12 is the total amount and the data falls between letters A and D).
E - H (24)
I - L (9)
M - P (62)
Q - T (18)
U - Z (0)

I wasn’t quite sure how to do this with a Dictionary.

Let’s say my model object consists of an Id and Title and that it’s called Discount.

At the moment, I have the following:

List<Discount> discounts = new List<Discount>();
Dictionary<string, Discount> dict = new Dictionary<string, Discount>();
foreach (DiscountDTO discount in discounts)
{
    if (discount.Title.StartsWith("A") ||
        discount.Title.StartsWith("B") ||
        discount.Title.StartsWith("C") ||
        discount.Title.StartsWith("D"))
    {
        dict.Add("A - D", discount);
    } else if (discount.Title.StartsWith("E") ||
        discount.Title.StartsWith("F") ||
        discount.Title.StartsWith("G") ||
        discount.Title.StartsWith("H"))
    {
        dict.Add("E - H", discount);
    } else if (discount.Title.StartsWith("I") ||
        discount.Title.StartsWith("J") ||
        discount.Title.StartsWith("K") ||
        discount.Title.StartsWith("L"))
    {
        dict.Add("I - L", discount);
    } else if (discount.Title.StartsWith("M") ||
        discount.Title.StartsWith("N") ||
        discount.Title.StartsWith("O") ||
        discount.Title.StartsWith("P"))
    {
        dict.Add("M - P", discount);
    } else if (discount.Title.StartsWith("Q") ||
        discount.Title.StartsWith("R") ||
        discount.Title.StartsWith("S") ||
        discount.Title.StartsWith("T"))
    {
        dict.Add("Q - T", discount);
    } else if (discount.Title.StartsWith("U") ||
        discount.Title.StartsWith("V") ||
        discount.Title.StartsWith("W") ||
        discount.Title.StartsWith("X") ||
        discount.Title.StartsWith("Y") ||
        discount.Title.StartsWith("Z"))
    {
        dict.Add("U - Z", discount);
    }
}

Thanks in advance.

Answer 1

you should use a List as the value of the dictionary:

static void Main(string[] args)
{

    List<Discount> list = new List<Discount>();
    list.Add(new Discount { Id = 1, Title = "Adam" });
    list.Add(new Discount { Id = 2, Title = "Ben" });
    list.Add(new Discount { Id = 3, Title = "Alex" });
    list.Add(new Discount { Id = 4, Title = "Daniel" });
    list.Add(new Discount { Id = 5, Title = "Ethan" });
    list.Add(new Discount { Id = 6, Title = "Howard" });
    list.Add(new Discount { Id = 7, Title = "Peter" });
    list.Add(new Discount { Id = 8, Title = "Tazz" });
    list.Add(new Discount { Id = 9, Title = "Steve" });
    list.Add(new Discount { Id = 10, Title = "Lyle" });

    Dictionary<string, List<Discount>> dic = new Dictionary<string, List<Discount>>();
    foreach (Discount d in list)
    {
        string range = GetRange(d.Title);
        if (dic.ContainsKey(range))
            dic[range].Add(d);
        else
            dic.Add(range, new List<Discount> { d });
    }
}

static string GetRange(string s)
{
    char c = s.ToLower()[0];
    if (c >= 'a' && c <= 'd')
        return "A - D";
    else if (c >= 'e' && c <= 'h')
        return "E - H";
    else if (c >= 'i' && c <= 'l')
        return "I - L";
    else if (c >= 'm' && c <= 'p')
        return "M - P";
    else if (c >= 'q' && c <= 't')
        return "Q - T";
    else if (c >= 'u' && c <= 'z')
        return "U - Z";
    return "";
}