C＃中的正则表达式问题

Question

I am trying to create a C# routine that removes all of the following prefixes and suffixes and returns just the root word of a domain:

var stripChars = new List<string> { "http://", "https://", "www.", "ftp.", ".com",  ".net", ".org", ".info", ".co", ".me", ".mobi", ".us", ".biz" };

I do this with the following code:

originalDomain = stripChars.Aggregate(originalDomain, (current, repl) => Regex.Replace(current, repl, @"", RegexOptions.IgnoreCase));

Which seems to work in almost all cases. Today, however, I discovered that setting "originalDomain" to "NameCheap.com" does not return:

NameCheap

Like it should, but rather:

NCheap

Can anyone look at this and tell me what is going wrong? Any help would be appreciated.

Answer 1

THis is normal: the dot in a regex means any character.

Therefore, .me matches ame in NameCheap .

Escape the dots with a backslash.

Also, you'd be better off using a dedicated URI API for this kind of operation.

Answer 2

I know this doesn't answer your question directly, but given the specific task you are trying to accomplish I would recommend trying something like this:

Uri uri = new Uri(originalDomain);
originalDomain = uri.Host;

EDIT:

If your input may not contain a scheme you can use the uri builder as notied in this post

var hostName = new UriBuilder(input).Host

Hope this helps.

Answer 3

Try this instead:

var stripChars = new List<string> {"http://", "https://", "www[.]", "ftp[.]", "[.]com", "[.]net", "[.]org", "[.]info", "[.]co", "[.]me", "[.]mobi", "[.]us", "[.]biz"};

The '.' character in Regular Expression is special, it stands for any character. This is one way to escape it.

However, as other have mentioned, your current solution for handling URL is brittle and you should explore other solution. Ideally you want to use something that really understands how to parse the URL syntax.