On Aug 28, 4:04 pm, "Guilherme Polo" <[EMAIL PROTECTED]> wrote: > On Thu, Aug 28, 2008 at 5:04 PM, Bart Kastermans > > <[EMAIL PROTECTED]> wrote: > > I have a file in which I am searching for the letter "i" (actually > > a bit more general than that, arbitrary regular expressions could > > occur) as long as it does not occur inside an expression that matches > > \\.+?\b (something started by a backslash and including the word that > > follows). > > > More concrete example, I have the string "\sin(i)" and I want to match > > the argument, but not the i in \sin. > > > Can this be achieved by combining the regular expressions? I do not > > know the right terminology involved, therefore my searching on the > > Internet has not led to any results. > > Try searching again with the "lookahead" term, or "negative lookahead". > > > > > I can achieve something like this by searching for all i and then > > throwing away those i that are inside such expressions. I am now just > > wondering if these two steps can be combined into one. > > > Best, > > Bart > > -- > >http://www.bartk.nl/ > > -- > >http://mail.python.org/mailman/listinfo/python-list > > -- > -- Guilherme H. Polo Goncalves
No dice: "This is called a positive lookbehind assertion. ...The contained pattern must only match strings of some fixed length." 'finditer' could make the 'combined into one' option more attractive though. -- http://mail.python.org/mailman/listinfo/python-list
