How to replace all XHTML/HTML line breaks (<br>) with new lines?
I would generally say "don't use regex to work with HTML", but, on this one, I would probably go with a regex, considering that <br> tags generally look like either :
<br>- or
<br/>, with any number of spaces before the/
I suppose something like this would do the trick :
$html = 'this <br>is<br/>some<br />text <br />!';$nl = preg_replace('#<br\s*/?>#i', "\n", $html);echo $nl;Couple of notes :
- starts with
<br - followed by any number of white characters :
\s* - optionnaly, a
/:/? - and, finally, a
> - and this using a case-insensitive match (
#i), as<BR>would be valid in HTML
You should be using PHP_EOL constant to have platform independent newlines.
In my opinion, using non-regexp functions whenever possible makes the code more readable.
$newlineTags = array( '<br>', '<br/>', '<br />',);$html = str_replace($newlineTags, PHP_EOL, $html);I am aware this solution has some flaws, but wanted to share my insights still.
If the document is well-formed (or at least well-formed-ish) you can use the DOM extension and xpath to find and replace all br elements by a \n text node.
$in = '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN""http://www.w3.org/TR/html4/strict.dtd"><html><head><title>...</title></head><body>abc<br />def<p>ghi<br />jkl</p></body></html>';$doc = new DOMDOcument;$doc->loadhtml($in);$xpath = new DOMXPath($doc);$toBeReplaced = array();foreach($xpath->query('//br') as $node) { $toBeReplaced[] = $node;}$linebreak = $doc->createTextNode("\n");foreach($toBeReplaced as $node) { $node->parentNode->replaceChild($linebreak->cloneNode(), $node);}echo $doc->savehtml();prints
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"><html><head><title>...</title></head><body>abcdef<p>ghijkl</p></body></html>edit: shorter version with only one iteration
$in = '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN""http://www.w3.org/TR/html4/strict.dtd"><html><head><title>...</title></head><body>abc<br />def<p>ghi<br />jkl</p></body></html>';$doc = new DOMDOcument;$doc->loadhtml($in);$xpath = new DOMXPath($doc);$linebreak = $doc->createTextNode("\n");foreach($xpath->query('//br') as $node) { $node->parentNode->removeChild($node);}echo $doc->savehtml();