c# - Regex Match.Value returning entire value, not the matched groups

Question

I am currently trying to achieve the relatively simple task of capturing values from a string which exist between sets of curly braces using a regular expression. The expression I have written works fine on a number of online tools I have tested it on, however this is not the case in .NET.

String str= "{Value1}-{Value2}.{Value3}";
Regex regex = new Regex( @"{(w+)}");

MatchCollection matches = regex.Matches(str);

foreach(Match match in matches)
{
    Console.WriteLine(match.Value);
}

I would expect to get 3 matches of "Value1", "Value2", "Value3". However .NET is also returning the brackets, i.e. "{Value1}", "{Value2}", "{Value3}".

Any help on how this can be achieved would be great.

Answer 1

You used capturing groups (...), so what you want is in the Groups[1]:

Regex regex = new Regex(@"{(w+)}");

MatchCollection matches = regex.Matches(str);

foreach (Match match in matches) {
    Console.WriteLine(match.Groups[1].Value);
} 

Another way is to use zero-width assertions:

Regex regex = new Regex(@"(?<={)(w+)(?=})");

MatchCollection matches = regex.Matches(str);

foreach (Match match in matches) {
    Console.WriteLine(match.Value);
} 

In this way the Regex will search for w+ that is preceded and followed by the { and }, but these two characters won't be part of the match.