Web scraping with regular expression, getting rid of html tags.

Hi all,

I am doing some webscraping code and consequently, I am using regular expressions. I need to isolate the words from a string, of course html tags should not be included. Html tags are words included in < > (e.g. br). Unfortunately, my code does not work out and I am wondering why. Here an example:

regexp('qu <qa>','(?!<)\w*(?!>)','match')

My expected results is 'qu' but instead I get 'qu' and 'q'. The code works with this string 'qu q'. What may I do to solve this issue?

thanks

Regards,

Pietro

The following code works regexp('qu qa','(?!<)\w*(?!>)','match')

Answer 1

[Guillaume]

The first part of your expression is a look-ahead. You want a look behind instead. Add a < before the !:

regexp('qu <qa>', '(?<!<)\w*(?!>)', 'match')

[pietro]

Yep!!! Thanks. What a mistake. Nevertheless, I found tags composed by more than a word, like:

   <td class="tdat">

How can I cut them out?

[Guillaume]

It's a lot more difficult to tell a regular expression not to match something than it is to tell it to match something. Therefore, I'd do it in two passes.

1. remove the tags:

notags = regexprep(yourstring, '<[^>]*>', '')

2. match whatever it is you want to match

matches = regexp(notags, '\w+', 'match')

[pietro]

thanks for your reply. I haven't thought of using regexprep