Question

I’ve got a problem. I use following regular expression:

---

Pattern =
  (?'name'\w+(?:\w|\s)*), \s*
  (?'category'\w+(?:\w|\s)*), \s*
  (?:
      \{ \s*
          [yY]: (?'year'\d+), \s*
          [vV]: (?'volume'(?:([1-9][0-9]*\.?[0-9]*)|(\.[0-9]+))+), \s*
      \} \s*
      ,? \s*
  )*

with IgnorePatternWhitespaces option.
Everything seemed fine in my application until I debugged it & encountered a problem.

---

var Year = default(UInt32);
// ...
if((Match = Regex.Match(Line, Pattern, Options)).Success)
{
    // Getting Product header information
    Name = Match.Groups["name"].Value;

    // Gathering Product statistics
    for(var ix = default(Int32); ix < Match.Groups["year"].Captures.Count; ix++)
    {
       // never get here
       Year = UInt32.Parse(Match.Groups["year"].Captures[ix].Value, NumberType, Culture);
    }
}

So in the code above.. In my case Match is always successful. I get proper value for Name but when turn comes to for loop program flow just passes it by. I debugged there’s no Captures in Match.Groups["year"]. So it is logical behavior. But not obvious to me where I’m wrong. Help!!

There is a previous connected post Extract number values enclosed inside curly brackets I made.

Thanks!

EDIT. Input Samples

Sherwood, reciever, {y:2008,V:5528.35}, {y:2009,V:8653.89}, {y:2010, V:4290.51}

• I need to capture 2008, 5528.35, 2009, 8653.89, 2010, 4290.51 values and operate with them as named groups.

2D EDIT

I tried using ExplicitCapture Option and following expression:

(?<name>\w+(w\| )*), (?<category>\w+(w\| )*), (\{[yY]:(?<year>\d+), *[vV]:(?<volume>(([1-9][0-9]*\.?[0-9]*)|(\.[0-9]+))+)\}(, )?)+

But that didn’t help.

Answer 1

Edit: You could simplify by matching everything until the next comma: [^,]*. Here’s a full code snippet to match your source data:

var testRegex = new Regex(@"
    (?'name'[^,]*),\s*
    (?'category'[^,]*),\s*
    ({y:(?'year'[^,]*),\s*
    V:(?'volume'[^,]*),?\s*)*",
    RegexOptions.IgnorePatternWhitespace);
var testMatches = testRegex.Matches(
    "Sherwood, reciev, {y:2008,V:5528.35}, {y:2009,V:8653.89}, {y:2010, V:4290.51}");
foreach (Match testMatch in testMatches)
{
    Console.WriteLine("Name = {0}", testMatch.Groups["name"].Value);
    foreach (var capture in testMatch.Groups["year"].Captures)
        Console.WriteLine("    Year = {0}", capture);
}

This prints:

Name = Sherwood
    Year = 2008
    Year = 2009
    Year = 2010