Regex: Match any punctuation character except . and _

Question

Is there an easy way to match all punctuation except period and underscore, in a C# regex? Hoping to do it without enumerating every single punctuation mark.

Answer 1

Use Regex Subtraction

[\p{P}-[._]]

See the .NET Regex documentation. I'm not sure if other flavors support it.

C# example

string pattern = @"[\p{P}\p{S}-[._]]"; // added \p{S} to get ^,~ and ` (among others)
string test = @"_""'a:;%^&*~`bc!@#.,?";
MatchCollection mx = Regex.Matches(test, pattern);
foreach (Match m in mx)
{
    Console.WriteLine("{0}: {1} {2}", m.Value, m.Index, m.Length);
}

Explanation

The pattern is a Character Class Subtraction. It starts with a standard character class like [\p{P}] and then adds a Subtraction Character Class like -[._], which says to remove the . and _. The subtraction is placed inside the [ ] after the standard class guts.

Answer 2

The answers so far do not respect ALL punctuation. This should work:

(?![\._])\p{P}

(Explanation: Negative lookahead to ensure that neither . nor _ are matched, then match any unicode punctuation character.)

Answer 3

Here is something a little simpler. Not words or white-space (where words include A-Za-z0-9 AND underscore).

[^\w\s.]

Answer 4

You could possibly use a negated character class like this:

[^0-9A-Za-z._\s]

This includes every character except those listed. You may need to exclude more characters (such as control characters), depending on your ultimate requirements.