DaniWeb Forum Index > Web Development > PHP

Replacing many newlines with 1 or 2 <br>'s

Please support our PHP advertiser: PostgreSQL or MySQL? Compare and contrast the two most popular open source databases

•

Join Date: Oct 2004

Posts: 274

Reputation: mmiikkee12 is an unknown quantity at this point

Solved Threads: 5

mmiikkee12 mmiikkee12 is offline

Offline

Posting Whiz in Training

Replacing many newlines with 1 or 2 <br>'s

Apr 27th, 2007

If I have a string like this:

Help with Code Tags

PHP Syntax (Toggle Plain Text)

blah
test
 
 
 
asdf

What kind of regex would I use to change all single newlines (like between 'blah' and 'test') to <.br> and all multiple newlines (like between 'test' and 'asdf') to a maximum of two <.br>'s?

I've tried these already:

 Help with Code Tags 
 php Syntax (Toggle Plain Text) 
// I had to change br tags to <.br> to make vB not remove them. I don't have a period in the tag in my actual code.
 
// Replaces each \n with one br tag each, so huge amounts of linebreaks if huge amount of newlines
$text = preg_replace("/(\n)+/m", '<.br>', $text);
 
// Same result
$text = preg_replace("/(\n)+/mU", '<.br>', $text);
 
// Puts a <br> after every character in my string (definitely not what I wanted)
$text = preg_replace("/(\n)*/m", '<.br>', $text);
 
// Inserts no newlines
$text = preg_replace("/\n+$/mU", '<.br>', $text);
// I had to change br tags to <.br> to make vB not remove them. I don't have a period in the tag in my actual code.

// Replaces each \n with one br tag each, so huge amounts of linebreaks if huge amount of newlines
$text = preg_replace("/(\n)+/m", '<.br>', $text);

// Same result
$text = preg_replace("/(\n)+/mU", '<.br>', $text);

// Puts a <br> after every character in my string (definitely not what I wanted)
$text = preg_replace("/(\n)*/m", '<.br>', $text);

// Inserts no newlines
$text = preg_replace("/\n+$/mU", '<.br>', $text);

I'm out of ideas. Anyone know what else I can try?

Last edited by mmiikkee12; Apr 27th, 2007 at 7:51 pm.

•

Join Date: Oct 2006

Posts: 13

Reputation: urolicious is an unknown quantity at this point

Solved Threads: 2

urolicious urolicious is offline

Offline

Newbie Poster

Re: Replacing many newlines with 1 or 2 <br>'s

Apr 28th, 2007

You can definately do that with regex, but I believe without would be faster:

eg:
[PHP]
function my_nl2br($str, $rep = "<br />", $max = 2) {
$arr = explode("\r\n", $str);
$str = '';
$nls = 0;
foreach($arr as $line) {
$str .= $line;
if (empty($line)) {
$nls++;
} else {
$nls = 0;
}
if ($nls < $max) {
$str .= $rep;
}
}
return substr($str, 0, strlen($str) - strlen($rep));
}[/PHP]

Usage:

[PHP]echo my_nl2br2($str);[/PHP]

I haven't tested it though...