Question

I am trying to pull the anchor text from a link that is formatted this way:

<h3><b>File</b> : <a href="/en/browse/file/variable_text">i_want_this</a></h3>

I want only the anchor text for the link : “i_want_this”

“variable_text” varies according to the filename so I need to ignore that.

I am using this regex:

<a href=\"\/en\/browse\/file\/variable_text\">(.*?)<\/a>

This is matching of course the complete link.

Answer 1

PHP uses a pretty close version to PCRE (PERL Regex). If you want to know a lot about regex, visit perlretut.org. Also, look into Regex generators like exspresso.

For your use, know that regex is greedy. That means that when you specify that you want something, follwed by anything (any repetitions) followed by something, it will keep on going until that second something is reached.

to be more clear, what you want is this:

1. <a href="
2. any character, any number of times (regex = .* )
3. ">
4. any character, any number of times (regex = .* )
5. </a>

beyond that, you want to capture the second group of “any character, any number of times”. You can do that using what are called capture groups (capture anything inside of parenthesis as a group for reference later, also called back references).

I would also look into named subpatterns, too – with those, you can reference your choice with a human readable string rather than an array index. Syntax for those in PHP are (?P<name>pattern) where name is the name you want and pattern is the actual regex. I’ll use that below.

So all that being said, here’s the “lazy web” for your regex:

<?php
$str = '<h3><b>File</b> : <a href="/en/browse/file/variable_text">i_want_this</a></h3>';
$regex = '/(<a href\=".*">)(?P<target>.*)(<\/a>)/';
preg_match($regex, $str, $matches);

print $matches['target'];
?>

//This should output "i_want_this"

Oh, and one final thought. Depending on what you are doing exactly, you may want to look into SimpleXML instead of using regex for this. This would probably require that the tags that we see are just snippits of a larger whole as SimpleXML requires well-formed XML (or XHTML).