I want to remove new lines from some html (with php) except in <pre> tags where whitespace is obviously important.
A:
If the html is well formed, you can rely on the fact that <pre> tags aren't allowed to be nested. Make two passes: First you split the input into block of pre tags and everything else. You can use a regular expression for this task. Then you strip new lines from each non-pre block, and finally join them all back together.
Note that most html isn't well formed, so this approach may have some limits to where you can use it.
troelskn
2009-09-13 22:02:52
A:
Split the content up. This is easily done with...
$blocks = preg_split('/<(|\/)pre>/', $html);
Just be careful, because the $blocks elements won't contain the pre opening and closing tags. I feel that assume the HTML is valid is acceptable, and therefore you can expect the pre-blocks to be every other element in the array (1, 3, 5, ...). Easily tested with $i % 2 == 1.
Example "complete" script (modify as you need to)...
<?php
//out example HTML file - could just as easily be a read in file
$html = <<<EOF
<html>
<head>
<title>test</title>
</head>
<body>
<h1>Title</h1>
<p>
This is an article about...
</p>
<pre>
line one
line two
line three
</pre>
<div style="float: right:">
random
</div>
</body>
</html>
EOF;
//break it all apart...
$blocks = preg_split('/<(|\/)pre>/', $html);
//and put it all back together again
$html = ""; //reuse as our buffer
foreach($blocks as $i => $block)
{
if($i % 2 == 1)
$html .= "\n<pre>$block</pre>\n"; //break out <pre>...</pre> with \n's
else
$html .= str_replace(array("\n", "\r"), "", $block, $c);
}
echo $html;
?>
Sam Bisbee
2009-09-14 00:02:54