Performing a subtotal on filtered data from a streamreader

Question

edit as question is unanswered

I have a filtered output based on 1 criteria (first 3 numbers are 110,210 or 310,to give 3 distinct groups) to console from streamreader.

Answer 1

string input = File.ReadAllText("file.dat");
var result = Regex.Matches(input, "(210|310|410).*?([A-C]{3})([0-9]{5})")
    .Cast()
    .Select(m => new { 
        P1 = m.Groups[1].Value, 
        P2 = m.Groups[2].Value, 
        P3 = Convert.ToInt32(m.Groups[3].Value)
    })
    .GroupBy(x => new{x.P1,x.P2})
    .Select(x=>String.Format("{0} {1} {2}",x.Key.P1,x.Key.P2,x.Sum(y=>y.P3)))
    .ToList();