Regex search-and-replace in database tables

Question

I'm using PHP and MySQL. Imagine a series of articles that all include the following HTML code:

</div>
<div id="Homes">
  <h2>Homes</h2>

However, there could be differences in whitespace, like this:

</div>
[WHITESPACE]
<div id="Homes"><h2>Homes</h2>

I'd like to know if it's possible to use regular expressions to insert something before the first div closing tag in the example above, like this:

[INSERT SOMETHING HERE]
</div>
<div id="Homes">
  <h2>Homes</h2

The regular expression would ignore whitespace and target the last div closing tag before div#Homes.

If you don't know the exact regular expression that would do this, that's fine. I just need to know if it can be done (and whether it can be done with phpMyAdmin or if I need a different program).

If it CANNOT be done, then I'm going to have to insert some code that can be replaced with str_replace. But it would be a lot simpler and cleaner if I could use regular expressions.

PS My page will actually include several similar divs/headings - Homes, Ecology, Environment, etc. I'd like to be able to insert content or features at the end of each section - but before the closing div tag in some cases.

Answer 1

You can use the following regex:

</div>(?=[\s\n\r]+<div id="Homes">)

Then replace with

[INSERT SOMETHING HERE]\n</div>

This will match the last </div> before the Homes div, not matter the number of newlines or whitespaces.

</div>
<div id="Homes">
  <h2>Homes</h2>

Explanation of regex:

• </div> match the </div>
• ?= is a forward lookup. Note that this is non capturing, and it will not be part of the match
• [\\s\\n\\r] match a whitespace or newline character

If you also want to match when everything is on one line then you would just replace + with * :

</div>(?=[\s\n\r]*<div id="Homes">)

matches the <\\div> in

</div><div id="Homes"><h2>Homes</h2><div id="Homes">