PHP Regex Match of Anchor Tag

Question

I am trying to use REGEX to split a string apart while maintaining the delimeters. I wish to split a very large and unpredictable string apart via anchor tags. I am using HTML tidy to ensure the tags are correct, however anything could come before or after the anchor tag I wish to match.

*PRECEDING-ANYTHING*<a *ANYTHING*>*ANYTHING*</a>*PROCEDING-ANYTHING*
*PRECEDING-ANYTHING*<a *ANYTHING*>*ANYTHING*</a>*PROCEDING-ANYTHING*

where the href URL could be anything and additional attributes such as 'target' could also be anything.

I've done a lot of searching and testing and either I am doing something wrong or the other answers on Stack Overflow do not apply.

Using

$parts= preg_split($pattern, $textWithAnchors, -1, PREG_SPLIT_DELIM_CAPTURE)

I was hoping to have $parts be similar to the following.

parts[0] is equal to *PRECEDING-ANYTHING*
parts[1] is equal to <a *ANYTHING*>*ANYTHING*</a>
and so forth

It is important that the regular expression capture the entire anchor tags and everything inside.

I would very much appreciate any help, I'm asking specifically for a regular expression that will accomplish this in PHP. I am aware that there are HTML parsers however, using REGEX is optimal in this situation. Maybe it will be a learning experiance though.

Please look at the `DOMDocument` class, it's much more hands-on and supports loading partial code. You could easily load one of your lines and let it find all `a`-tags. — Cobra_Fast, Nov 14 '13 at 15:26
See the first answer here: http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags — elixenide, Nov 14 '13 at 15:28
Thanks for the comments. I have done a lot of reading on those other methods and at the moment to the best of my knowledge regular expressions are still the best way to complete this task. I have seen this sort of operation successfully done with PHP regular expressions before and with to complete it via regex. I understand that this may be a dirty way of doing it, but in that case it will be a learning experiance. Also, I wanted to point out that the example I used above are not just lines, the *ANYTHING* text could be paragraphs, other HTML, chars, line breaks etc. — user2992699, Nov 14 '13 at 15:36
You really dont want to use regular expressions for this. But here goes /.*().*/i — Jesper Blaase, Nov 14 '13 at 15:37
If it isn't too much work, I would appreciate a simple answer of what regular expression pattern would match the entire anchor tag. You may all then sit back and laugh at me as I attempt to get it to work if that helps ;p — user2992699, Nov 14 '13 at 15:37
Edit, I've tried '/(.*?)<\/a>/s' and '/]+>/i' and '##' and a few others I will pull up. — user2992699, Nov 14 '13 at 15:41
Thank you very much, and sorry if I came off arrogant or pushy. I truly do appreciate the help, in a few minutes I got the answer. Cheers — user2992699, Nov 14 '13 at 15:44
Also for future reference, /.*().*/i should be /.*().*/i otherwise an unkown modifier error occurs in PHP. — user2992699, Nov 14 '13 at 16:07

Bohemian · Answer 1 · 2014-03-27T12:07:36.537

Using PREG_SPLIT_DELIM_CAPTURE won't help you, because that returns text captured in group 1 of the delimiter regex as a separate element, but you want the delimiters to be included with the elements.

To specify delimiters that don't consume input, use regex look arounds.
This code does the job:

$parts= preg_split('/(?=<a)|(?<=\/a>)/', $textWithAnchors);

It's splitting using a look-ahead for the open tag, an da look behind for the closing tag.

See a live demo of this code splitting your example as required.

PHP Regex Match of Anchor Tag

1 Answers1