PHP - Complicated Regex extraction - php

Question

I have some strings to parse, and it's getting a little more complex.
<?php
$notecomments = '
This is the first of the notes, and so whatever comes later is appended.<br>
(<b>John Smith</b>) at <b class="datetimeGMT">2012-02-07 00:00:20 GMT</b><hr>This is a comment posted<br><br>(<b>Alex Boom</b>) at <b class="datetimeGMT">2013-02-07 00:08:06 GMT</b><hr>And let's put some more in here<br />with a new line.';
if(preg_match_all('/\(<b>(?:(?!\(<b>).)*/s', $notecomments, $matches)){
print_r($matches);
}
/* result of code:
Array
(
[0] => Array
(
[0] => (<b>John Smith</b>) at <b class="datetimeGMT">2012-02-07 00:00:20 GMT</b><hr>This is a comment posted<br><br>
[1] => (<b>Alex Boom</b>) at <b class="datetimeGMT">2013-02-07 00:08:06 GMT</b><hr>And let's put some more in here<br />with a new line.
)
)
*/
?>
I'm able to loop through "appended" notes, since I have indicators to work with in the preg_match_all regex rules.
However, many of my notes have text before the first iteration from my preg_match_all.
(in this case: "This is the first of the notes, and so whatever comes later is appended.")
My first goal was met. Which is the result of my code above. I'm extracting appended notes to the first note.
My next goal is to detect anything before the first iteration. And that's where I'm stuck. (detecting anything before the first iteration, in my regex statement above)

Answer 1

i use preg_replace_callback with two regex for this
like
$notecomments = "This is the first of the notes, and so whatever comes later is appended.<br>(<b>John Smith</b>) at <b class=\"datetimeGMT\">2012-02-07 00:00:20 GMT</b><hr>This is a comment posted<br><br>(<b>Alex Boom</b>) at <b class=\"datetimeGMT\">2013-02-07 00:08:06 GMT</b><hr>And let's put some more in here<br />with a new line.";
$output=preg_replace_callback(array("~<b (.*?)>(.+?)</b>~si","~<b>(.+?)</b>~si"),function($matches){
if(isset($matches[2])){
print_r($matches[2]."\n");
}else{
print_r($matches[1]."\n");
}
return '';},' '.$notecomments.' ');
output:
2012-02-07 00:00:20 GMT
2013-02-07 00:08:06 GMT
John Smith
Alex Boom