Another Regular Expression quickie

Anon

I need to match 3 newlines (carriage returns) in a row in a text document, and replace them with one set of 5 stars (*****)

Here's the code (that doesn't work):

$search = "'[\n{3}]'";
$replace = "*****";
$theresult = preg_replace($search, $replace ,$contents);

Any help is appreciated...
Dan

smarlowe

Here's how to do it with ereg_replace (I avoid perl regexes when possible, because I find posix regexes much simpler, and generally faster.)

$search = "\n{3}";
$replace = "*****";
$result = ereg_replace($search,$replace,$text);

Hope that helps. Note that [] brackets are used to hold a RANGE of characters, and since you aren't replacing BOTH \n and something else, you don't need them.

If you needed to replace both 3 \n and 3 \m with ***** then you could do it like this:

$search = "[\n\m]{3}";

Note the bound goes on the outside, since it bounds the TWO choices of \n or \m. Note however, that this regex would replace \n\m\n with ***** as well as any combination of \n or \m.

If you wanted to restrict it to JUST 3\n or 3\m, then you'd use a branch (i.e. | symbol) like so:

$search = "\n{3}|\m{3}";

I haven't tested those, so I won't guaranteed them as being syntactically correct, but they should be close enough to figure out what I mean and play a bit with it.

If you're on a linux box, use "man 7 regex" to get a nice little basic help page on posix regular expressions.

Anon

Scott,
Thanks for the reply, but I tried your syntax and for some reason it doesn't work when the number is in curly brackets.
Without the number, it works, but I need it to be 3 consecutive spaces (Otherwise, I get 3 sets of 5 stars). I tried ereg_replace and preg_replace.

I even made a simple file:
a

and used your syntax:

$search = "\n{3}";
$replace = "*****";
$result = ereg_replace($search,$replace,$text);

but it didn't accomplish anything. Only when I deleted the {3}, it displayed a ** b **c

Dan

Anon

This regex should work

$contents = "Im looking for a few \n\n\n newlines";

$search = "/\n{3}/";
$replace = "*****";
$theresult = preg_replace($search, $replace ,$contents);

print $theresult;

Mark
http://www.hdwt.com

Anon

Thanks guys,
there were some rogue spaces screwing things up...I solved it using the following:
(I tried EVERYTHING else...):

$search = "/(\n(\s)\n(\s)\n(\s))/";
$replace = "****";
$text = preg_replace($search, $replace, $contents);

Dan

smarlowe

Dan, fyi, I tested the first regex I posted and it definitely worked. Are you sure you were replacing JUST \n? maybe your box had extra characters in the stream or something.

anyway, glad to see you got it working.