Multiple regular expression interfere - php

Question

I use regex to create html tags in plain text. like this
loop
$SearchArray[] = "/\b(".preg_quote($user['name'], "/").")\b/i";
$ReplaceArray[] = '$1';
-
$str = preg_replace($SearchArray, $ReplaceArray, $str);
I'm looking for a way to not match $user['name'] in a tag.

Answer 1

You could use preg_replace_callback()
for 5.3+:
$callback = function($match) using ($user) {
return ''.$match[1].'';
};
$regex = "/\b(".preg_quote($user['name'], "/").")\b/i";
$str = preg_replace_callback($regex, $callback, $string);
for 5.2+:
$method = 'return \'\'.$match[1].\'\';';
$callback = create_function('$match', $method);
$regex = "/\b(".preg_quote($user['name'], "/").")\b/i";
$str = preg_replace_callback($regex, $callback, $string);

Answer 2

So the problem is that you're making several passes over the document, replacing a different user name in each pass, and you're afraid you'll unintentionally replace a name inside a tag that was created in a previous pass, right?
I would try to do all of the replacements in one pass, using preg_replace_callback as #ircmaxwell suggested, and one regex that can match any legal user name. In the callback function, you look up the matched string to see if it's a real user's name. If it is, return the generated link; if not, return the matched string for reinsertion.

Answer 3

It looks like you're trying to add a bunch of anchors to a document. Have you thought of using SimpleXML. This assumes that the anchor tags are part of a larger xhtml document.
//$xhtml_doc is some xhtml doc's path
$doc = simplexml_load_file($xhtml);
//NOTE: find the parent element for all these anchors (maybe with xpath)
//example: $parent = $doc->xpath('//div[#id=parent]');
foreach($user as $k => $v){
$anchor = $doc->addChild('a', $v['name']);
$anchor->addAttribute('href', $v['url']);
}
return $doc->asXML();
simpleXML helps me a lot in these situations. It'll be a lot faster than regex, even if this isn't exactly what you want to do.