python regex "negative lookahead assertions" problems

[Tim Chase]

>>>> import re
>>>> line='2009-11-22 12:15:441  lmqkjsfmlqshvquhsudfhqf qlsfh qsduidfhqlsiufh qlsiuf qldsfhqlsifhqlius dfh warning qlsfj lqshf lqsuhf lqksjfhqisudfh qiusdfhq iusfh'
>>>> re.match('.*(?!warning)',line)
> <_sre.SRE_Match object at 0xb75b1598>
> 
> I would expect that this would NOT match as it's a negative lookahead and warning is in the string.

This first finds everything (".*") and then asserts that 
"warning" doesn't follow it, which is correct in your example. 
You may have to assert that "warning" doesn't exist at every 
point along the way:

   re.match(r'(?:(?!warning).)*',line)

which will match up-to-but-not-including the "warning" text.  If 
you don't want it at all, you'd have to also anchor the far end

   re.match(r'^(?:(?!warning).)*$',line)

but in the 2nd case I'd just as soon invert the test:

   if 'warning' not in line:
     do_stuff()

-tkc