在这种情况下正确使用正则表达式是什么？

Question

I have necessity to parse and convert some kind of URL part, here is how I do that now:

Regex s_re = new Regex(@"^/(lang_([^/]*)/)?([^/]*)([^\?]*)\??(.*)$", RegexOptions.IgnoreCase);

const string Url = "...";

MatchCollection matches = s_re.Matches(Url);
if(matches.Count==0) return false;//can't find matches

string strLang = s_re.Replace(Url, @"$2");
string strAddr = s_re.Replace(Url, @"$3");

Am I correctly understand that in this case my URL is parsed 3 times (original match and each replace). And in the best case it should be parsed only once and the result should be used.

I suspect that instead of following call to "Replace" I should use something else, but can't find what exactly.

Could you please advise?

Thanks.

Answer 1

You should do it like this:

Match match = regexData.Match(line);
if (!match.Success) return false;
string val1 = match.Groups[0].Value;
string val2 = match.Groups[1].Value;

Also, you probably want to use RegexOptions.CultureInvariant with that RegexOptions.IgnoreCase because otherwise it uses casing conventions of local culture and not unicode. more on msdn