Regular Expression to convert from PHP to C#

AngryC

Hello guys, I have the following Regular Expression, I want to convert it from PHP to C#. $aVar = preg_replace("/[\r\n]{1,2}(.+)\#(.*)[\r\n]{1,2}/U", "$myRightVar\\1$myCenterVar\\2$myLeftVar\r", $aVar); ( http://www.php.net/preg\_replace ) I tried a lot but I failed. Can you please help me. Thanks.

Lost User

The Regex is okay, at least it compiles and Expresso doesn't complain. What shall it match actually? regards

AngryC

I'm new to C#. This is the first time I'm using Regular expression. Can you give me the complete C# tag please? What the code does is taking any line that contains # charachter and add $myRightVar at the beginning of the line then replace # with $myCenterVar and add $myLeftVar at the end of the line.

Kevin McFarlane

Download Expresso. You'll find it very helpful. And it generates C# code for you. http://www.ultrapico.com/Expresso.htm[^] Kevin

Graham Nimbley

string regex=@"[\r\n]{1,2}(.+)\#(.*)[\r\n]{1,2}";
string replace=String.Format("{0}\\1{1}\\2{2}\r",myRightVar,myCenterVar,myLeftVar);

string output=Regex.Replace(input,regex,replace);

Haven't got VS in front of me, but this (hopefully) should work. Graham. -- modified at 15:34 Sunday 25th June, 2006

AngryC

It's almost working... the problem is I'm NOT getting the old left text and the old right text shown. I'm getting \1 and \2. What's wrong? Many thanks.

Lost User

This is a different approach, maybe it works for you?

string regex = @"[\r\n]{1,2}(.+)\#(.*)[\r\n]{1,2}";

Match m = Regex.Match(input, regex);
if (m.Success)
{
string output = String.Format("{0}{1}{2}{3}{4}\r", myRightVar, m.Groups[1], myCenterVar, m.Groups[2], myLeftVar);
Console.WriteLine(output);
}

Probably this might also work, it's way shorter:

string output2 = Regex.Replace(input, regex, String.Format("{0}$1{1}$2{2}\r", myLeftVar, myCenterVar, myRightVar));

regards

AngryC

Thanks a lot but it didn't work for me :( The string I am parsing contains the following: bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla. toto toto toto # toto toto toto toto toto toto # toto toto toto toto toto toto # toto toto toto toto toto toto # toto toto toto bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla. So I want to add alter the content on the following way: bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla. [myLeftVar]toto toto toto [myCenterVar] toto toto toto[myRightVar] [myLeftVar]toto toto toto [myCenterVar] toto toto toto[myRightVar] [myLeftVar]toto toto toto [myCenterVar] toto toto toto[myRightVar] [myLeftVar]toto toto toto [myCenterVar] toto toto toto[myRightVar] And so on... bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla. Please help.

Graham Nimbley

This should be it.

string regex=@"(.+)\#(.+)\r\n";
string replace=String.Format("{0}$1{1}$2{2}\r\n","Left","Center","Right");

string output=Regex.Replace(input,regex,replace);

I've tweaked the regex as I was having problem with it. I've dumped the code I used to test it:

using System;
using System.Text.RegularExpressions;

public class Testy
{
public static void Main()
{

string input="bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla.\r\n\r\n"+
"toto toto toto # toto toto toto\r\n"+
"toto toto toto # toto toto toto\r\n"+
"toto toto toto # toto toto toto\r\n"+
"toto toto toto # toto toto toto\r\n\r\n"+
"bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla bla";

	string regex=@"(.+)\\#(.+)\\r\\n";
	string replace=String.Format("{0}$1{1}$2{2}\\r\\n","Left","Center","Right");

	string output=Regex.Replace(input,regex,replace);
	
	Console.WriteLine(output);
}

}

AngryC

Thanks a lot Graham it worked :)

Graham Nimbley

Good to know. :) Regexs are good fun, but can be a pain in the a**e sometimes!! :rolleyes:

AngryC

I have this left :-O $content = preg_replace('#[color=([^-]+)-(.*)[/color]#Uis', '$2', $content); This is simply to parse bbcode color tag, e.g. [color=red]text[/color] Please help.

Graham Nimbley

Hi

using System;
using System.Text.RegularExpressions;

public class Testy
{
public static void Main()
{
string input="This is a [color=red]red[/color] color and this is a [color=blue]blue[/color] color.";
string regex=@"\[color=[^\]]*?\](.*?)\[/color\]";

	string output=Regex.Replace(input,regex,"$1");
	Console.WriteLine(output);
}

}

There was a couple of things wrong with the regex. The original was greedy, and is now lazy. Also some escaping of ']' and '[' was needed. Graham -- modified at 14:41 Monday 26th June, 2006

AngryC

Thanks a lot but what if I want to change the brakets type, say: -color=red- text text -color!- How can I parse it to: text text

Graham Nimbley

string regex=@"\[color=([^\]]*?)\](.*?)\[/color\]";
string replace=@"<color=$1>$2</color>";

string output=Regex.Replace(input,regex,replace);

If you are intending to place bbcode for a certain number of tags, it might be easier to use a generic regex. -- modified at 17:58 Monday 26th June, 2006

AngryC

Many thanks, It worked, but not when it's nested: text text text text [color=red]hello [color=green]ok[/color] test ok[/color] Is there an easy solution for this?

Graham Nimbley

The easy way would be to treat the opening and closing tags independently of each other.

using System;
using System.Text.RegularExpressions;

public class Testy
{
public static void Main()
{
string input="This is a [color=red]red sentence with [color=blue]some blue[/color] words[/color].";

	// Replace open color tag
	input=Regex.Replace(input,@"\\\[color=(\[^\\\]\]\*?)\\\]","<color=$1>");
	
	// Replace close color tag
	input=Regex.Replace(input,@"\\\[/color\\\]","</color>");
	
	Console.WriteLine(input);
}

}

The hard way would involve some complex regexs. Will try to come up with something. Graham. [Edit] Hmmm. It appears that this might be pretty difficult. The problem is that regexs by definition match up by looking forward. To look for nested tags, requires searching the text in tree-wise fashion. To do this in linear text requires requires bilaterial searching, looking forward from the left at the same time looking backwards from the right. Problem is that regexes are virtually impossible to do proper backwards searching. It may be possible to achieve the same effect with some creative code along side regexs. -- modified at 19:13 Monday 26th June, 2006

AngryC

Worked, again :) Which one is better for the closing tab in your opinion: This: output = input.Replace("[/color]", ""); Or this: input=Regex.Replace(input,@"\[/color\]",""); The first one is faster right? I PHP normal function is faster than regular expression, is it the samething in C#? -- modified at 19:16 Monday 26th June, 2006

Graham Nimbley

They both do the same job. The first it a straight substitution, the second a regex. The first would be marginally faster to perform. Have you read my edit on the harder solution?

AngryC

I just did. Anyway, the easy method is more than enough for me. I really appreciate your help.