Solved

Finding the start and end character positions / indexes of a RegEx match.

Posted on 2008-10-14
6
582 Views
Last Modified: 2008-10-15
Given the code below, when the RegEx matches the incoming string to the incoming template string, I would like to somehow determine the start and end character inde of the exact match.

Obviously in this case, start would be 1. But how do you calcualte the last character position  of the match, which in this case in the incoming string is a single quotation ( ' ) ??

Bare in mind that even though this example contains an exact match, it is possible that the incoming string might be:

string incoming = @"UCS+21'
UCD+14+3'
MORETEXT+nothing'
ANDMORE+goes+here'";

Which is why I can't just use a simple function like Right() or something similar. I need to actually get the last position of the matched item in the incoming string.

Thanks.

using System;
using System.Text.RegularExpressions;
namespace retest
{
    class Program
    {
        static void Main(string[] args)
        {
            string incoming = @"UCS+21'
UCD+14+3'";
            string incomingTemplate = @"UCS+{UcmHeader}'
UCD+{UcmHeader}+{UcmSummary}'";
            string repattern = Regex.Replace(Regex.Replace(Regex.Replace(incomingTemplate, @"\+", @"\+"), @"\{", @"(?<"), @"\}", @">.*?)");
            Regex reParse = new Regex(repattern);
            if (reParse.IsMatch(incoming))
            {
                Match m = reParse.Match(incoming);
                for (int gIdx = 1; gIdx < m.Groups.Count; gIdx++)
                {
                    Console.WriteLine("[" + reParse.GetGroupNames()[gIdx] + "] = " + m.Groups[gIdx].Value);
                }
            }
            Console.ReadLine();
        }
    }
}

Open in new window

0
Comment
Question by:djcheeky
  • 5
6 Comments
 
LVL 27

Expert Comment

by:ddrudik
ID: 22715973
0
 
LVL 27

Expert Comment

by:ddrudik
ID: 22715985
That would show the start index of the match, add the string length to that value to get the ending index.
0
 
LVL 27

Expert Comment

by:ddrudik
ID: 22715998
I guess you could always use the length property to add to the index property to get the ending index:
http://msdn.microsoft.com/en-us/library/system.text.regularexpressions.capture.length.aspx
0
Is Your AD Toolbox Looking More Like a Toybox?

Managing Active Directory can get complicated.  Often, the native tools for managing AD are just not up to the task.  The largest Active Directory installations in the world have relied on one tool to manage their day-to-day administration tasks: Hyena. Start your trial today.

 
LVL 27

Accepted Solution

by:
ddrudik earned 500 total points
ID: 22716037
Console.WriteLine("[" + reParse.GetGroupNames()[gIdx] + "] = " + m.Groups[gIdx].Value);
Console.WriteLine("captures[0] value: " + m.Captures[0].Value);
Console.WriteLine("captures[0] index: " + m.Captures[0].Index);
Console.WriteLine("captures[0] length: " + m.Captures[0].Length);
0
 

Author Comment

by:djcheeky
ID: 22718878
Thanks ddrudik

As you can tell, I have broken up all my little regex issues into smaller problems and then posted them here on the forums, with which you have helped the most (so thanks again for that).

What I am going to do now is try and combine them into one process, which will more than likely lead to more gray hairs - but let's see how it goes :)

I appreciate all your help.
Regards
Paolo
0
 
LVL 27

Expert Comment

by:ddrudik
ID: 22720478
Glad I could help, thanks for the question and the points.
0

Featured Post

Master Your Team's Linux and Cloud Stack

Come see why top tech companies like Mailchimp and Media Temple use Linux Academy to build their employee training programs.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I have been reconstructing a PHP-based application that has grown into a full blown interface system over the last ten years by a developer that has now gone into business for himself building websites. I am not incredibly fond of writing PHP code o…
This article aims to explain the working of CircularLogArchiver. This tool was designed to solve the buildup of log file in cases where systems do not support circular logging or where circular logging is not enabled
Learn how to match and substitute tagged data using PHP regular expressions. Demonstrated on Windows 7, but also applies to other operating systems. Demonstrated technique applies to PHP (all versions) and Firefox, but very similar techniques will w…
Explain concepts important to validation of email addresses with regular expressions. Applies to most languages/tools that uses regular expressions. Consider email address RFCs: Look at HTML5 form input element (with type=email) regex pattern: T…

831 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question