regex problem ..

[Steve Holden]

Analog Kid wrote:
> Hi guys:
> Thanks for your responses. Points taken. Basically, I am looking for a
> combination of the following ...
> [^\w] and %(?!20) ... How do I do this in a single RE?
> 
> Thanks for all you help.
> Regards,
> AK
> 
> On Mon, Dec 15, 2008 at 10:54 PM, Steve Holden <steve at holdenweb.com
> <mailto:steve at holdenweb.com>> wrote:
> 
>     Analog Kid wrote:
>     > Hi All:
>     > I am new to regular expressions in general, and not just re in python.
>     > So, apologies if you find my question stupid :) I need some help with
>     > forming a regex. Here is my scenario ...
>     > I have strings coming in from a list, each of which I want to check
>     > against a regular expression and see whether or not it "qualifies". By
>     > that I mean I have a certain set of characters that are
>     permissible and
>     > if the string has characters which are not permissible, I need to flag
>     > that string ... here is a snip ...
>     >
>     > flagged = list()
>     > strs = ['HELLO', 'Hi%20There', '123123@#@']
>     > p =  re.compile(r"""[^a-zA-Z0-9]""", re.UNICODE)
>     > for s in strs:
>     >     if len(p.findall(s)) > 0:
>     >         flagged.append(s)
>     >
>     > print flagged
>     >
>     > my question is ... if I wanted to allow '%20' but not '%', how
>     would my
>     > current regex (r"""[^a-zA-Z0-9]""") be modified?
>     >
>     The essence of the approach is to observe that each element is a
>     sequence of zero or more "character", where character is "either
>     letter/digit or escape." So you would use a pattern like
> 
>     "([a-zA-Z0-9]|%[0-9a-f][0-9a-f])+"
> 
> 
Did you *try* the above pattern?

regards
 Steve
-- 
Steve Holden        +1 571 484 6266   +1 800 494 3119
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