regular expression

Bengt Richter wrote:
> On Sat, 26 Mar 2005 02:07:15 GMT, aaron <asteele at berkeley.edu> wrote:>>>>>pattern.sub(':', '375 mi. south of U.C.B is 3.4 degrees warmer.')>>'375 mi: south of U:C:B is 3.4 degrees warmer:'>>>>so this works, but not in the following case:>>>>>pattern.sub(':', '.3')>>> Brute force the exceptional case that happens at the start of the line?> >  >>> import re>  >>> pattern = re.compile(r'^[.]|(?!\d)[.](?!\d)')>  >>> pattern.sub(':', '375 mi. south of U.C.B is 3.4 degrees warmer.')>  '375 mi: south of U:C:B is 3.4 degrees warmer:'>  >>> pattern.sub(':', '.3')>  ':3'>  >>> pattern.sub(':', '3.')>  '3:'

Be careful... the OP has assumed something that isn't true,
and Bengt's fix isn't sufficient:

 >>> import re>>> s = 'x.3'>>> pattern = re.compile(r'^[.]|(?!\d)[.](?!\d)')>>> pattern.sub(':', '.3')
':3'
 >>> pattern.sub(':', s)
'x.3'

So the OP's "this works" comment was wrong.

Suggestion: whip up a variety of automated test cases and
make sure you run them all whenever you make changes to
this code...

(No, I don't have a solution to the continuing problem,
other than to wonder whether the input data really requires
all these edge cases to be handled properly.)

-Peter