分割逗号分隔的字符串以计算重复项

Question

I have the following data in my database (comma separated strings):

"word, test, hello"
"test, lorem, word"
"test"
...
etc

How can I transform this data into a Dictionary whereby each string is separated into each distinct word together with the number of times that it occurs, ie

{"test", 3},  {"word", 2}, {"hello", 1}, {"lorem", 1}

I will have approximately 3000 rows of data in case this makes a difference to any solution offered. Also I am using .NET 3.5 (and would be interested to see any solution using linq)

Answer 1

IEnumerable<string> strings = ...;

Dictionary<string,int> result = strings.SelectMany(s => s.Split(','))
                                       .GroupBy(s => s.Trim())
                                       .ToDictionary(g => g.Key, g => g.Count());

Answer 2

Here is something like a pseudocode(haven't tried to compile it)

List<string> allRows = getFromDatabase();

var result = new Dictionary<string, int>();
foreach (string row in allRows)
{
   string[] words = row.Split(',');

   foreach (string word in words)
      if (result.ContainsKey(word))
         result[word]++;
      else
         result.Add(word, 1);
}