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

Question

pietro 2017-6-3

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/343153-web-scraping-with-regular-expression-getting-rid-of-html-tags

编辑： pietro 2017-6-4

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')

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Guillaume 2017-6-3

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/343153-web-scraping-with-regular-expression-getting-rid-of-html-tags#answer_269431

在 MATLAB Online 中打开

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')

3 个评论
显示 1更早的评论隐藏 1更早的评论

Guillaume 2017-6-3

在 MATLAB Online 中打开

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 2017-6-4