Question

I have the following string that would require me to parse it via Regex in C#.

Format: rec_mnd.rate.current_rate.sum.QWD.RET : 214345

I would like to extract our the bold chars as group objects in a groupcollection.

QWD = 1 group
RET = 1 group
214345 = 1 group

what would the message pattern be like?

Answer 1

It would be something like this:

string s = "Format: rec_mnd.rate.current_rate.sum.QWD.RET : 214345";
Match m = Regex.Match(s, @"^Format: rec_mnd\.rate\.current_rate\.sum\.(.+?)\.(.+?) : (\d+)$");
if( m.Success )
{
    Console.WriteLine(m.Groups[1].Value);
    Console.WriteLine(m.Groups[2].Value);
    Console.WriteLine(m.Groups[3].Value);
}

The question mark in the first two groups make that quantifier lazy: it will capture the least possible amount of characters. In other words, it captures until the first . it sees. Alternatively, you could use ([^.]+) in those groups, which explicitly captures everything except a period.

The last group explicitly only captures decimal digits. If your expression can have other values on the right side of the : you’d have to change that to .+ as well.