Python re - escape coincidental parentheses in regex pattern

Question

I am having trouble with the regex in the following code:

import mechanize
import re

br = mechanize.Browser()
br.set_handle_robots(False)
br.addheaders = [(         


        

Answer 1

You need to escape the parenthesis since they have a special meaning:

<a href="javascript:__doPostBack\('(.*?)','(.*?)'\)">
                             HERE^            HERE^

Note that, ideally, you should not be parsing HTML with regex (even though your pattern is quite specific and I don't think this is that bad). Instead, parse HTML with, say, BeautifulSoup, locate the a element, get the href attribute value and then extract the desired substrings with regex.