Develop Reference

Regex - find all lines after a match:

Given the following text in an email body:
DO NOT MODIFY SUBJECT LINE ABOVE. Sending this email signifies my Request to Delay distribution of this Product Change Notification (PCN) to 9001 (Qwest). The rationale for this Request to Delay is provided below:
This is the reason I need to capture.
It can be many many lines long.
And go on for a long time
I'm trying to capture all the text that follows "... is provided below:".
The pattern being passed into BodyRegex is:
.*provided below:(?<1>.*)
The code being executed is:
Regex regex2 = new Regex(BodyRegex, RegexOptions.IgnoreCase | RegexOptions.Multiline);
string note = null;
Match m2 = regex2.Match(body);
if (m2.Success)
{
note = m2.Groups[1].Value;
}
The match is not being found.
What match pattern do I need to use to capture all lines of text following "is provided below:"?

The section (?...) is look ahead syntax which isn't what you want.
You might want to try a look behind instead:
(?<=provided below:)[.|\n|\W|\w]*
I've had issues with .NET not recognizing end of line characters the way you'd expect it to using .* , hence the or conditions.

Use this regex with single line option
^.*?provided below:(.*?)$
works here

Need To Fail A Match If It Is Successful

I have this pattern in C#:
string WWPNMatchString = #"port-wwn\s+\(vendor\)\s+:(?<wwpn>..:..:..:..:..:..:..:..)";
I have file with these two lines that occur in pairs several times in the file:
port-wwn (vendor) :50:01:73:80:12:60:01:41
permanent-port-wwn (vendor) :50:01:73:80:12:60:01:41
I only want to match the first line. There are other lines that screw up the data I am parsing where the second line looks like this:
permanent-port-wwn (vendor) :00:00:00:00:00:00:00:00
So, I don't want to match the line that includes permanent. I could do a separate if to check the incoming string but that is messy. the online site I use to check my regular expressions fails the second line, but C# doesn't after the code is compiled.

It occurred to me that the pattern that I don't want always starts with 00:
so I changed the regex to:
string WWPNMatchString = #"port-wwn\s+\(vendor\)\s+:(?<wwpn>[1-9].:..:..:..:..:..:..:..)";
this will exclude anything where the wwpn group starts with 0 - the value I am after, valid values never start with 0.

I assume you're reading the file line by line, and each line is processed as a separate string?
You can force the match to begin at the start of the string by using ^, like this:
#"^port-wwn\s+\(ven...
This will exclude the lines starting with "permanent-".

A regex
string WWPNMatchString = #"^port-wwn\s+\(vendor\)\s+:(?<wwpn>..:..:..:..:..:..:..:..)";

Regex between, from the last to specific end

Today my wish is to take text form the string.
This string must be, between last slash and .partX.rar or .rar
First I tried to find edge's end of the word and then the beginning. After I get that two elements I merged them but I got empty results.
String:
http://hosting.xyz/1234/15-game.part4.rar.html
http://hosting.xyz/1234/16-game.rar.html
Regex:
Begin:(([^/]*)$) - start from last /
End:(.*(?=.part[0-9]+.rar|.rar)) stop before .partX.rar or .rar
As you see, if I merge that codes I won't get any result.
What is more, "end" select me only .partX instead of .partX.rar
All what I want is:
15-game.part4.rar and 16-game.rar
What i tried:
(([^/]*)$)(.*(?=.part[0-9]+.rar|.rar))
(([^/]*)$)
(.*(?=.part[0-9]+.rar|.rar))
I tried also
/[a-zA-Z0-9]+
but I do not know how select symbols.. This could be the easiest way. But this select only letters and numbers, not - or _.
If I could select symbols..

You don't really need a regex for this as you can merely split the url on / and then grab the part of the file name that you need. Since you didn't mention a language, here's an implementation in Perl:
use strict;
use warnings;
my $str1="http://hosting.xyz/1234/15-game.part4.rar.html";
my $str2="http://hosting.xyz/1234/16-game.rar.html";
my $file1=(split(/\//,$str1))[-1]; #last element of the resulting array from splitting on slash
my $file2=(split(/\//,$str2))[-1];
foreach($file1,$file2)
{
s/\.html$//; #for each file name, if it ends in ".html", get rid of that ending.
print "$_\n";
}
The output is:
15-game.part4.rar
16-game.rar

Nothing could be simpler! :-)
Use this:
new Regex("^.*\/(.*)\.html$")
You'll find your filename in the first captured group (don't have a c# compiler at hand, so can't give you working sample, but you have a working regex now! :-) )
See a demo here: http://rubular.com/r/UxFNtJenyF

I'm not a C# coder so can't write full code here but I think you'll need support of negative lookahead here like this:
new Regex("/(?!.*/)(.+?)\.html$");
Matched Group # 1 will have your string i.e. "16-game.rar" OR "15-game.part4.rar"

Use two regexes:
start to substitute .*/ with nothing;
then substitute \.html with nothing.
Job done!

Meta-regular expressions?

I wrote a file routing utility (.NET) some time ago to examine a file's location and name pattern and move it to some other preconfigured place based on the match. Fairly simple, straightforward kinda stuff. I had included the possibility of minor transformations through a series of regular expression search-and-replace actions that could be assigned to the file "route", with the intent of adding header rows, replacing commas with pipes, that sort of thing.
So now I have a new text feed that consists of a file header, a batch header, and a multitude of detail records under the batches. The file header contains a count of all detail records in the file, and I have been asked to "split" the file in the assigned transformations, essentially producing a file for each batch record. This is fairly straightforward, as well, but the kicker is, there is an expectation to update the file header for each file to reflect the detail count.
I do not even know if this is possible with pure regular expressions. Can I count the number of matches of a group in a given text document and replace the count value in the original text, or am I going to have to write a custom transformer for this one file?
If I have to write another transformer, are there suggestions on how to make it generic enough to be reusable? I'm considering adding an XSLT transformer option, but my understanding of XSLT is not so great.
I've been asked for an example. Say I have a file like so:
FILE001DETAILCOUNT002
BATCH01
DETAIL001FOO
BATCH02
DETAIL001BAR
this file will be split and stored in two locations. The files will look like this:
FILE001DETAILCOUNT001
BATCH01
DETAIL001FOO
and
FILE001DETAILCOUNT001
BATCH01
DETAIL001BAR
so the sticker for me is the file header's DETAILCOUNT value.

Regular expressions by themselves can't count the number of matches they've made (or, better put, they don't expose that to the regex user), so you do need additional program code to keep track of this.
A regex can only capture text that exists somewhere in the source material, it can't generate new text. So unless you can find the number you need explicitly at some point in the source, you're out of luck. Sorry.

My program first breaks the text into batches.
I think you'll agree that resequencing the detail number is the trickiest part. You can do it with a MatchEvaluator delegate.
Regex.Replace (
text, // the text replace part of
#"(?<=^DETAIL)\d+", // the regex pattern to find.
m => (detailNum++).ToString ("000"), // replacement (evaluated for each match)
RegexOptions.Multiline);
See how the preceeding code increments detailNum at the begining of each batch.
var contents =
#"FILE001DETAILCOUNT002
BATCH01
DETAIL001FOO
BATCH02
DETAIL001BAR";
// foreach batch....
foreach (Match match in Regex.Matches (contents, #"BATCH\d+\s+(?:(?!BATCH\d+).*\s*)+"))
{
Console.WriteLine ("==============\r\nFile\r\n================");
int batchNum = 1;
int detailNum = 1;
StringBuilder temp = new StringBuilder ();
TextWriter file = new StringWriter (temp);
// Your file here instead of my stringBuilder/StringWriter
string batchText = match.Value;
int count = Regex.Matches (batchText, #"^DETAIL\d+", RegexOptions.Multiline).Count;
file.WriteLine ("FILE001DETAILCOUNT{0:000}", count);
string newText = Regex.Replace (batchText, #"(?<=^BATCH)\d+", batchNum.ToString ("000"), RegexOptions.Multiline);
newText = Regex.Replace (
newText,
#"(?<=^DETAIL)\d+",
m => (detailNum++).ToString ("000"), // replacement (evaluated for each match)
RegexOptions.Multiline);
file.Write (newText);
Console.WriteLine (temp.ToString ());
}
prints
==============
File
================
FILE001DETAILCOUNT001
BATCH001
DETAIL001FOO
==============
File
================
FILE001DETAILCOUNT001
BATCH001
DETAIL001BAR

Parsing a text file into fields using multiple delimiter types

I'm attempting to parse log files from a chat using c#, the problem I'm running into is that it's not really designed for parsing as it doesn't use standard delimiters. Here's an example of a typical line from the file:
2010-08-09 02:07:54 [Message] Skylar Morris -> (ATL)City Waterfront: I'll be right back
date time messageType userName -> roomName: message
The fields I'd like to store are:
Date and Time joined as a DateTime type
messageType
userName
roomName
message
If it was separable by a standard delimiter like space, tab, or comma it would be fairly simple but I'm at a loss on how to attack this.
As a follow up, using this code as a template:
List<String> fileContents = new List<String>();
string input = #"2010-08-09 02:07:54 [Message] Skylar Morris -> (ATL)City Waterfront: I'll be right back";
string pattern = #"(.*)\[(.*)\](.*)->(.+?):(.*)";
foreach (string result in Regex.Split(input, pattern))
{
fileContents.Add(result.Trim());
}
I'm getting 7 elements (one empty before and after) the 5 that are expected. How can I rectify this?
foreach (string result in Regex.Split(input, pattern)
**.Where(result => !string.IsNullOrEmpty(result))**)
{
fileContents.Add(result.Trim());
}
Ok, managed to resolve it with the above code.

You know that old adage about "Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems."?
well, in this case, you really do need regular expressions.
this one should cover you in this case:
([\d]{4}-[\d]{2}-[\d]{2} [\d]{2}:[\d]{2}:[\d]{2}) \[([\w]+)\] ([a-zA-Z0-9 ]+) -> (\([\w]+\)[a-zA-Z0-9 ]+): (.*)
you should really test it though. I just threw this together and it may be not handling everything you could see.

Try this:
.*\[(.*)\](.*)->(.+?):(.*)
It uses the fact that message is in square brackets []
name is between [] and ->
room name is between -> and :
and message is everything afterwards. :)