[xborder]

Thank you komari, i cant right now but i'll try it later. But according to the wiki, for episodes without a season, you have to use an empty pair of parentheses for the season. I'm quite confused about what it is supposed to obtain from the expression.
I've made something like this:

Code:

(?<=[/\._ \-])()(\d{2,3})

and according to http://www.pythonregex.com/, it returns an empty string and the number of the episode. Isn't that what its supposed to return?