473,799 Members | 3,134 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

Regex question: Retrieve group names in code?

[Pardon the crossposting, but it seemed appropriate given the lack of a
dedicated group]

Is there any way to retrieve the name of a capture group from the classes
provided in the RegularExpressi ons namespace? GroupCollection implements
ICollection and IEnumerable, not IDictionary, so there doesn't seem to be
any means to retrieve key values.

While I realize this isn't generally needed in a production scenario (you
normally KNOW what your groups are called), it is quite necessary if you're
building a general regular expression evaluation app (like The Regulator or
Regex Workbench).

In case I'm not being clear, consider the following example (error-trapping
and most braces omited for brevity--and in two languages to justify the
crosspost):

[You have a form with three text boxes, txtRegex, txtString, and txtOutput.
The user puts "(?<month>\d{1, 2})/(?<day>\d{1,2})/(?<year>\d{4})" into
txtRegex and "Today's date is 12/1/2004. Where has the year gone?" in
txtString and clicks the Evaluate button.]

-------VB--------
Private Sub btnEval_Click(B yVal sender As Object, ByVal e As
System.EventArg s) Handles btnEval.Click
Dim rgx As Regex, m As Match
rgx = New Regex(txtRegex. Text)
m = rgx.Match(txtSt ring.Text)
If m.Success Then
For Each g As Group In m.Groups
If g.Index <> 0 Then
' This is what I'd LIKE to do
txtOutput.Appen dText("Group '" & g.Name & "' = '" & g.Value
& "'" & Environment.New Line)
End If
Next
End If
End Sub
--------------------

--------C#--------
private void btnEval_Click(o bject sender, System.EventArg s e)
{
Regex rgx = new Regex(txtRegex. Text);
Match m = rgx.Match(txtSt ring.Text);
if (m.Success)
foreach (Group g in m.Groups)
if (g.Index != 0)
// This is what I'd LIKE to do
txtOutput.Appen dText("Group '" + g.Name + "' = '" + g.Value
+ "'\r\n");
}
--------------------

I would then like the output text box to contain:

Group 'month' = '12'
Group 'day' = '1'
Group 'year' = '2004'

(And pardon my C# if I made any syntax or style mistakes.)
Nov 16 '05 #1
1 3910
"Jeff Johnson [MVP: VB]" <i.***@enough.s pam> wrote in news:usM8pp91EH A.4028
@TK2MSFTNGP15.p hx.gbl:
I would then like the output text box to contain:

Group 'month' = '12'
Group 'day' = '1'
Group 'year' = '2004'


You can use the method: GroupNameFromNu mber to retreive the group name.
To get the GroupNumber, you can just iterate through the group collection.

--
Lucas Tam (RE********@rog ers.com)
Please delete "REMOVE" from the e-mail address when replying.
http://members.ebay.com/aboutme/coolspot18/
Nov 16 '05 #2

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

1
1316
by: Jeff Johnson [MVP: VB] | last post by:
Is there any way to retrieve the name of a capture group from the classes provided in the RegularExpressions namespace? GroupCollection implements ICollection and IEnumerable, not IDictionary, so there doesn't seem to be any means to retrieve key values. While I realize this isn't generally needed in a production scenario (you normally KNOW what your groups are called), it is quite necessary if you're building a general regular...
2
5984
by: Jose | last post by:
There's something for me to learn with this example, i'm sure :) Given this text: "....." and my first attempt at capture the groups: "(?:\)" RegExTest gives me what i expect: 6 captured groups: Contact, Region, All ContractRegion, ASIA PACIFIC, Japan, Japan. However, with this C# code, i just get 2 capture groups: ",
8
7856
by: Richard Lionheart | last post by:
Hi All, I tried using RegEx, but the compiler barfed with "The type of namespace 'RegEx' could not be found. Prior to this, I had the same problem with MatchCollection, but discovered it's in the namespace "System.Text.RegularExpressions;" and that namespace is, in turn, defined in the namespace "System", according to MSDN at http://msdn2.microsoft.com/en-us/library/c75he57e(en-us,VS.80).aspx. So adding "using...
1
1605
by: George Durzi | last post by:
Consider this excerpt from some HTML. (This is a copy from View->Source, except for the comment) <TABLE WIDTH=100% CELLPADDING=0 CELLSPACING=0 border=0> <?xml version="1.0" encoding="UTF-16"?> <!-- need to extract whatever is here --> </TABLE> I need to extract all the HTML that would be in the <!-- need to extract whatever is here --> section. So I did the following.
1
1461
by: K. Shier | last post by:
while writing a RegEx, you implicily name your Groups: \b(?<month>\d{1,2})/(?<day>\d{1,2})/(?<year>\d{2,4})\b so, why isn't .Name a property of a System.Text.RegularExpressions.RegEx.Group? more importantly, how can you refer to a Group by name in code?
17
3982
by: clintonG | last post by:
I'm using an .aspx tool I found at but as nice as the interface is I think I need to consider using others. Some can generate C# I understand. Your preferences please... <%= Clinton Gallagher http://forta.com/books/0672325667/
17
2795
by: Mark | last post by:
I must create a routine that finds tokens in small, arbitrary VB code snippets. For example, it might have to find all occurrences of {Formula} I was thinking that using regular expressions might be a neat way to solve this, but I am new to them. Can anyone give me a hint here? The catch is, it must only find tokens that are not quoted and not commented; examples follow
1
1163
by: TtfnJohn | last post by:
I have two small scripts that while on the surface should both work the problem is they don't. Here's the first one: import re testString = 'Thap,fpvi,*!wtyd@*.dip.t-dialin.net:*!ylx@*.dip.t- dialin.net:*!lajaz@*.dip.t-dialin.net::::::' reobj = re.compile(r"(.*),(.*),(.*):::(.*):::(.*)")
4
312
by: pedrito | last post by:
I have a regex question and it never occurred to me to ask here, until I saw Jesse Houwing's quick response to Phil for his Regex question. I have some filenames that I'm trying to parse out of URLs. (href=("|')http://.www\.thesite\.com/.{1,7}/)(?<filename>.) This generally works, but the problem is some of the image files have ..th.jpg at the end to indicate thumbnails. I want to exclude those. I just want the ones that don't have...
3
250
by: mathieu | last post by:
I do not understand what is wrong with the following regex expression. I clearly mark that the separator in between group 3 and group 4 should contain at least 2 white space, but group 3 is actually reading 3 +4 Thanks -Mathieu import re
0
9688
marktang
by: marktang | last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look ! Part I. Meaning of...
0
9546
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
0
10491
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. Here is my compilation command: g++-12 -std=c++20 -Wnarrowing bit_field.cpp Here is the code in...
0
10268
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth. The Art of Business Website Design Your website is...
1
10247
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For most users, this new feature is actually very convenient. If you want to control the update process,...
0
6809
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert into image. Globals.ThisAddIn.Application.ActiveDocument.Select();...
0
5593
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
2
3762
muto222
by: muto222 | last post by:
How can i add a mobile payment intergratation into php mysql website.
3
2941
bsmnconsultancy
by: bsmnconsultancy | last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.