• Status: Solved
  • Priority: Medium
  • Security: Public
  • Views: 436
  • Last Modified:

Regular expression

Looks like my understanding of negative lookaheads is lacking.

I have this test string:
<tr>
<td>text</td>
<td></td>
<td>code</td>
</tr>
<tr>
<td>text</td>
</tr>
<tr>
<code>
</tr>

Open in new window

and the following expression:
(?sm)<tr>.*?(text).*?(code).*?</tr>

Open in new window


I want to match "text" followed by "code" in the same row.
That is, "code" should follow "text" before "<\tr>".
In the sample, the only match should be
<tr>
<td>text</td>
<td></td>
<td>code</td>
</tr>

Open in new window


How can I write the regular expression for that?
0
Dan Craciun
Asked:
Dan Craciun
1 Solution
 
käµfm³d 👽Commented:
I believe this is what you are after:

(?sm)<tr>.*?(text)(?:.(?!</tr>))+?(code)

Open in new window


Basically, you simply look ahead of the current character matched by the dot, and you check to make sure that the following text is not the closing row tag. There may be a more elegant way to do it, but this should suffice for your current need.

You may find my article on regular expression lookaround useful:  http://www.experts-exchange.com/Programming/Languages/Regular_Expressions/A_4318-Regular-Expression-Lookaround-Demystified.html
0
 
Dan CraciunIT ConsultantAuthor Commented:
Yup.
I kept writing the lookahead as
(?:.*(?!</tr>))
and it refused to work.

Thank you, kaufmed.
0

Featured Post

Keep up with what's happening at Experts Exchange!

Sign up to receive Decoded, a new monthly digest with product updates, feature release info, continuing education opportunities, and more.

Tackle projects and never again get stuck behind a technical roadblock.
Join Now