Minimize LINQ string token counter

Question

Followup on answer to an earlier question.

Is there a way to further reduce this, avoiding the external String.Split call? The goal is an associative

Answer 1

Getting rid of String.Split doesn't leave many options on the table. One option is Regex.Matches as spender demonstrated, and another is Regex.Split (which doesn't give us anything new).

Rather than grouping you could use either of these approaches:

var target = src.Split(new[] { ' ', ',', ';' }, StringSplitOptions.RemoveEmptyEntries);
var result = target.Distinct()
                   .Select(s => new { Word = s, Count = target.Count(w => w == s) });

// or dictionary approach
var result = target.Distinct()
                   .ToDictionary(s => s, s => target.Count(w => w == s));

The Distinct call is needed to avoid duplicate items. I went ahead and expanded the characters to split on to get the actual words devoid of punctuation. I found the first approach to be the quickest using spender's benchmarking code.

Back to the requirement to order the results from your previously referenced question, you could easily extend the first approach as follows:

var result = target.Distinct()
                   .Select(s => new { Word = s, Count = target.Count(w => w == s) })
                   .OrderByDescending(o => o.Count);

// or in query form

var result = from s in target.Distinct()
             let count = target.Count(w => w == s)
             orderby count descending
             select new { Word = s, Count = count };

EDIT: got rid of the Tuple since the anonymous type was close at hand.