Use regex to find specific string not in html tag

Question

I\'m having some difficulty with a specific Regex I\'m trying to use. I\'m searching for every occurrence of a string (for my purposes, I\'ll say it\'s \"mystring\") i

Answer 1

Another regex to search that worked for me

(?![^<]*>)_mystring_

Source: https://stackoverflow.com/a/857819/1106878

Answer 2

Why use regex?

For xhtml, load it into XDocument / XmlDocument; for (non-x)html the Html Agility Pack would seem a more sensible choice...

Either way, that will parse the html into a DOM so you can iterate over the nodes and inspect them.

Answer 3

Ignoring that are there indeed other ways, and that I'm no real regex expert, but one thing that popped into my head was:

• find all the mystrings that ARE in tags first - because I can't write the expression to do the opposite :)
• change those to something else
• then replace all the other mystring (that are left not in tags) as you need
• restore the original mystrings that were in tags

So, using <[^>]*?(mystring)[^>]*> you can find the tagged ones. Replace those with otherstring. Do you normal replace on the mystrings that are left. Replace otherstring back to mystring

Crude but effective....maybe.

Answer 4

When your regex processor doesn't support variable length look behind, try this:

(<.+?>[^<>]*?)(_mystring_)([^<>]*?<.+?>)

Preserve capture groups 1 and 3 and replace capture group 2:

For example, in Eclipse, find:

(<.+?>[^<>]*?)(_mystring_)([^<>]*?<.+?>)

and replace with:

$1_newString_$3

(Other regex processors might use a different capture group syntax, such as \1)

Answer 5

This should do it:

(?<!<[^>]*)_mystring_

It uses a negative look behind to check that the matched string does not have a < before it without a corresponding >

Answer 6

A quick and dirty alternative is to use a regex replace function with callback to encode the content of tags (everything between < and >), for example using base64, then run your search, then run another callback to decode your tag contents.

This can also save a lot of head scratching when you need to exclude specific tags from a regex search - first obfuscate them and wrap them in a marker that won't match your search, then run your search, then deobfuscate whatever is in markers.