Regex question

[AMP]

Hello,
I have a long string that I need to take a section out of and use.
The section I need always starts with "XX XX XX XX XX"
and always ends with "YY YY YY YY YY"
I want to throw away the rest and use whats between the 2 Marker
strings.
I am not sure how to do this with Regex.
Any help would be appreciated
Thanks,
Mike

 

[Kevin Spencer]

(?<=XX XX XX XX XX).*(?=YY YY YY YY YY)

Uses a positive Look-behind, and a positive Look-ahead.

--
HTH,

Kevin Spencer
Microsoft MVP
Chicken Salad Shooter
http://unclechutney.blogspot.com

A man, a plan, a canal, a palindrome that has.. oh, never mind.

 

[wfairl]

I believe you're looking for named groups.

your regular expression would look something like "XX XX XX XX
XX(?<data>.*?)YY YY YY YY YY"

Then enumerate the matches to find the value for the "data" group in
each one.

http://www.regular-expressions.info/named.html

 

[AMP]

I am new at regex, How do I use this in a statement. I want to operate
on the string between the 2 Markers.

Thnaks
Mike

 

[Thomas T. Veldhouse]

Hello,
I have a long string that I need to take a section out of and use.
The section I need always starts with "XX XX XX XX XX"
and always ends with "YY YY YY YY YY"
I want to throw away the rest and use whats between the 2 Marker
strings.
I am not sure how to do this with Regex.
Any help would be appreciated

A quick and dirty example for you:

Regex regex = new Regex(@"^XX XX XX XX XX(?<centervalue>.+)YY YY YY YY YY");
Match match = regex.Match("XX XX XX XX XXTest StringYY YY YY YY YY");
if (match.Success)
System.Console.WriteLine("Matched Text = {0}",
match.Groups[@"centervalue"].Value);

The output should be "Test String".

 

[Kevin Spencer]

Hi Mike,

The way that the regular expression I posted works is that look-arounds are
non-capturing patterns. They indicate that the pattern indicated must match,
but it is not part of the match. So, to translate my regular expression:

(?<=XX XX XX XX XX).*(?=YY YY YY YY YY)

A match is zero or more of any character. It must be preceded by "XX XX XX
XX XX XX" and it must be followed by "YY YY YY YY YY YY". So that, for
example, in the string:

XX XX XX XX XX123 ABCYY YY YY YY YY

The match will be "123 ABC"

In the string:

XX XX XX XX XX.....YY YY YY YY YY

The match will be "..."

In the string

XX XX XX XX XX123 ABC

There is no match (no "YY..." sequence following)

I'm not sure what the question "How do I use this in a statement" means. But
here is the authoritative Regex reference:

http://msdn2.microsoft.com/en-us/library/system.text.regularexpressions.regex.aspx

--
HTH,

Kevin Spencer
Microsoft MVP
Chicken Salad Shooter
http://unclechutney.blogspot.com

A man, a plan, a canal, a palindrome that has.. oh, never mind.

 

[Ebbe Kristensen]

A quick and dirty example for you:

Regex regex = new Regex(@"^XX XX XX XX XX(?<centervalue>.+)YY YY YY YY
YY");

Since the OP talks about "a section", this is probably better:

Regex regex = new Regex(@"^.*XX XX XX XX XX(?<centervalue>.+)YY YY YY YY
YY.*$");

Ebbe

 

[Thomas T. Veldhouse]

Since the OP talks about "a section", this is probably better:

Regex regex = new Regex(@"^.*XX XX XX XX XX(?<centervalue>.+)YY YY YY YY
YY.*$");

Agreed.