Question

I need to make a regex which matches content between tags like this:

<tag>
    <b> Match Me </b>
</other-closing-tag>

It should match only the content between the same tag. So the result should be something like this:

1 match:
<b> Match Me </b>
Match me

And I need to do it in PHP, but I don’t think that this is that important…

Answer 1

Use regular expression back references, which you can read more about under the following link.

• PHP: Back references – Manual

Though parsing html with regular-expressions is never a good idea, but I’m going to pretend that you are going to use this information for a completely different problem. 😉

---

Example snippet

In the below we are saying that the contents of our end-tag should be the same as what is matched by our first group ([^>]+), by using \1 inside our closing tag.

$data =<<<EOT
  <awesome-tag> match-me </awesome-tag>
  <error-tag>   match-me </err0r-tag>
  <super-tag>   match-me </super-tag>
  <error-tag>   match-me </err0r-tag>
  <awesome-tag> match-me </awesome-tag>
EOT;

preg_match_all ('/<([^>]+)>.*?match-me.*?<\/\1>/s', $data, $matches);

print_r ($matches);

output

Array
(
  [0] => Array
  (
    [0] => <awesome-tag> match-me </awesome-tag>
    [1] => <super-tag>   match-me </super-tag>
    [2] => <awesome-tag> match-me </awesome-tag>
  )

  [1] => Array
  (
    [0] => awesome-tag
    [1] => super-tag
    [2] => awesome-tag
  )
)