SortedList for Letter Frequency?

Question

Just wondering what data type you guys would recommend for counting up the occurrences of letters A->Z in words, and THEN sorting from Most Frequent letter to Least Frequent?

SortedList<string, int> sl = new SortedList<string, int>()
for (char i = 'A'; i <= 'Z'; i++)
{
sl.Add(i.ToString(), 0);
}

lends itself pretty well to getting a distribution (so that the integer is incremented with each occurrence of 'A', 'B', 'C' etc.)

In the 'olden days' (using C++) I'd probably have sorted a fixed array (26 of a char/int struct) - can you suggest a better way in C#?

Would received wisdom dictate using ICompareTo(), Sort or something?

Sam Hobbs · Answer

There are probably easier ways but the following works. using System; using System.Collections.Generic; using System.Linq; namespace _83705 { class Program { static void Main(string[] args) { String s = FSPFWODNQINSEGDRHRFPMEDOGNWAIUFGBWIVSDGM; int[] FreqArray = new int[26]; foreach (char c in s.ToCharArray()) ++FreqArray[c - 'A']; Dictionary > FreqMap = new Dictionary >(); List FreqList; int ArrayFreq; for (int i = 0; i { ArrayFreq = FreqArray[i]; if (FreqMap.TryGetValue(ArrayFreq out FreqList)) FreqList.Add((char)(i + 'A')); else { FreqList = new List (); FreqList.Add((char)(i + 'A')); FreqMap[ArrayFreq] = FreqList; } } IEnumerable Sorted = from kvp in FreqMap orderby kvp.Key select new FreqCharPair(kvp.Key kvp.Value); foreach (var Pair in Sorted) { Console.Write({0} Pair.Freq); foreach (char c in Pair.CharList) Console.Write( {0} c); Console.WriteLine(); } } class FreqCharPair { public int Freq; public List CharList; public FreqCharPair(int Freq List CharList) { this.Freq = Freq; this.CharList = CharList; } } } }

Sam Hobbs · Answer

Yeah that pseudo SQL stuff is LINQ and it is certainly powerful and still a mystery to me in many ways. Quite often C# developers use implicit types (var) for the result of a LINQ. I don't like implicit types; I prefer explict types such as IEnumerable.

Tj · Answer

Thanks very much Sam. Yeah I'd had a look at the IEnumerable interface in the Help File (but hadn't quite worked out how to use it - all that 'pseudo SQL'). Thanks again.