How to store large ordered data?

Store data within alphabetically ordered letters (A - D, E - H, I - L, etc) using Dictionary

• 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:

  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 ""; }