Question

I am using an application required by this project that must utilize regular expression inputs to pre-filter data that may come in the from of html / javascript.

I have read the article decrying the use of regex filtering html; I however must in this situation.

The issue I need help with (which seems like can not easily be explained) is finding the TAGS that contain within data_1.

<TAG>
     .
     ..
     ...
     data_1
     ...
     ..
     .
</TAG>

I have tried many different approaches however my overall experience with regex is limited.

Example 1:

\<TAG.*\bdata_1\b.*?/TAG\>

Does not work as it actually grabs the first that exists passing by /TAG> until it finds “data_1” then ends at the next following /TAG>

I know I am currently on the right track, I however started learning Regex about 2 days ago and am not quite there yet.

Any links, comments, advice would be most appreciated.

Edit

It still selects all preceding TAGS.

***BEGIN***
<TAG>
    ....
    .....
</TAG>
<TAG>
   ...
   data_1
   ...
</TAG>
***END***

When it should be:

<TAG>
    ....
    .....
</TAG>
***BEGIN***
<TAG>
   ...
   data_1
   ...
</TAG>
***END***

Answer 1

This regex would probably work:

<TAG>(?!.*?</TAG>.*?data_1).*?data_1.*?</TAG>

You can see the result here: http://regexr.com?2v5qt