Regular Expressions...

[MRAB]

Ken D'Ambrosio wrote:
> Hi, all.  As a recovering Perl guy, I have to admit I don't quite
> "get" the re module.  For example, I'd like to do a few things (I'm
> going to use phone numbers, 'cause that's what I'm currently dealing
> with):
 > 12345678900 -- How would I:
 > - Get just the area code?
 > - Get just the seven-digit number?
> 
> In Perl, I'd so something like m/^1(...)(.......)/; and then I'd have
> that stuff in $1 and $2, respectively.  But the Python stuff simply
> isn't clicking for me.  If anyone could supply concrete examples of 
> how to do the problem, above, that would be terrific.
> 
Perl puts the captured text into variables as a side-effect, which, from
the Python point of view, is undesirable 'magic'. The Python way is for
the result to be returned like any normal function or method call:

     match = re.search(r"^1(...)(.......)", phone_number)
     # match is now a match object if successful or None if unsuccessful
     if match:
         area_code = match.group(1)
         local_code = match.group(2)
         # or:
         # area_code, local_code = match.groups()

No magic involved!

(In this case simple string slicing would be simpler and faster.)