Negation in regular expressions

[Paddy]

Paddy wrote:
> George Sakkis wrote:
> > It's always striked me as odd that you can express negation of a single
> > character in regexps, but not any more complex expression. Is there a
> > general way around this shortcoming ? Here's an example to illustrate a
> > use case:
> >
> > >>> import re
> > # split with '@' as delimiter
> > >>> [g.group() for g in re.finditer('[^@]+', 'This @ is a @ test ')]
> > ['This ', ' is a ', ' test ']
> >
> > Is it possible to use finditer to split the string if the delimiter was
> > more than one char long (say 'XYZ') ? [yes, I'm aware of re.split, but
> > that's not the point; this is just an example. Besides re.split returns
> > a list, not an iterator]
> >
> > George
>
> If your wiling to use groups then the following will split
>
> >>> [g.group(1) for g in re.finditer(r'(.+?)(?:@#|$)', 'This @# is a @# test ')]
> ['This ', ' is a ', ' test ']
>
> - Paddy.

Here is another wrapping of the same finditer call that just allows you
to call .group() on the result

>>> class G(object):
... 	def __init__(self, x):
... 		def grp(x=x):
... 			return x
... 		self.group = grp
...
>>> [g.group() for g in (G(g.group(1)) for g in re.finditer(r'(.+?)(?:@#|$)', 'This @# is a @# test '))]
['This ', ' is a ', ' test ']
>>> 

- Paddy.