Regex for Mailto links

Question

Hi,

I'm trying to create a regex to match me email address from html pages.

I want to match 2 types of email:

<a href="mailto:[e-mail]">[e-mail]</a>

and

<a href="mailto:[e-mail]?subject=123">[e-mail]</a>

 

I've used this regex but it didn't work:

Match match = Regex.Match("<a href=\"mailto:[e-mail]?subject=1234", "mailto:(?<Email>.+)\\?|\"");

I think it has something with greedy...

 

Another question:

This is my string.

string x = "hell

<br/>

oooooooooooooooooooooooooooooooo";

How can i match only the first o?

I've tried this but it didn't work for me:

Match match = Regex.Match("helloooooooooooooooooooooooo","hell(?<GroupName>)o");

I want that the math.Groups["GroupName"].Value will return me only the first o

how do i do it?

Answer 1

Hello BRegex,

Below, the answers to your questions:

 

using System;
using System.Text.RegularExpressions;

namespace c64e13cb_0e36_482f_bc23_85d68bd3583f
{
    internal class Program
    {
        private static void Main()
        {
            // Email question
            const string emailPattern =
                   @"([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})";

            const string pattern =
                    "(" +
                        @"(?<withsubject>" + @"(?<=mailto\:)" + emailPattern + @"(?=\?)" + ")" +
                        "|" +
                        @"(?<withoutsubject>" + @"(?<=mailto\:)" + emailPattern + @"(?="")" + ")" +
                    ")";

            const string s = @"<a href=""mailto:[e-mail]"">[e-mail]</a>" +
                             @"<a href=""mailto:[e-mail]?subject=123"">[e-mail]</a>";

            var r = new Regex(pattern);
            MatchCollection mc = r.Matches(s);

            foreach (Match m in mc)
            {
                string withsubject = m.Groups["withsubject"].Value;
                string withoutsubject = m.Groups["withoutsubject"].Value;

                if (!string.IsNullOrEmpty(withsubject))
                    Console.WriteLine("Email with subject: {0}", withsubject);
                if (!string.IsNullOrEmpty(withoutsubject))
                    Console.WriteLine("Email without subject: {0}", withoutsubject);
            }

            // The o question
            Match match = Regex.Match("helloooooooooooooooooooooooo", "hell(?<GroupName>o)");

            Console.WriteLine("The o question: {0}", match.Value);

            Console.ReadKey();
        }
    }
}

Kind regards,

 

---

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Answer 2

On Mon, 6 Feb 2012 14:46:36 +0000, BRegex wrote:

 

>

>

>Hi,

>

>I'm trying to create a regex to match me email address from html pages.

>

>I want to match 2 types of email:

>

><a href="mailto:[e-mail]">[e-mail]</a>

>

>and

>

><a href="mailto:[e-mail]?subject=123">[e-mail]</a>

>

> 

>

>I've used this regex but it didn't work:

>

>

>Match match = Regex.Match("<a href=\"mailto:[e-mail]?subject=1234", "mailto:(?<Email>.+)\\?|\"");

>

>

>

>

>I think it has something with greedy...

 

It is always helpful if you lay out exactly what you want your regex to return (see the sticky about How to Ask A Regex Question).

Making an assumption that what you wish to return is:

 

[e-mail]

[e-mail]?subject=123

 

then try this regex:

 

"(?<=mailto:)[^\"]+(?=\">)"

 

(and I'm not sure if the lookahead at the end is really necessary).

 

 

>

> 

>

>Another question:

>

>This is my string.

>

>string x = "hell

><br/>

>

>oooooooooooooooooooooooooooooooo";

>

>

>

>How can i match only the first o?

>

>I've tried this but it didn't work for me:

>

>

>Match match = Regex.Match("helloooooooooooooooooooooooo","hell(?<GroupName>)o");

>

>

>

>

>I want that the math.Groups["GroupName"].Value will return me only the first o

>

>how do i do it?

 

\A(?:.(?<!o))*(?<First_o>o)

 

 

---

Ron