Negative regular expressions (searching for "i" not inside command)

[Guilherme Polo]

On Thu, Aug 28, 2008 at 5:04 PM, Bart Kastermans
<kasterma at math.wisc.edu${hostname}> 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