\w in regular expression

[Marcello Pietrobon]

Hello,

I am reading
http://www.amk.ca/python/howto/regex/

But there is an incongruence:
In the paragraph 2.1: Matching Character:

|\w|
Matches any alphanumeric character; this is equivalent to the class
[a-zA-Z0-9_].

|\W|
Matches any non-alphanumeric character; this is equivalent to the
class |[^a-zA-Z0-9_]|.

Which is fine with me and the same as in Perl and congruent with:

|\d|
Matches any decimal digit; this is equivalent to the class [0-9].

|\D|
Matches any non-digit character; this is equivalent to the class
|[^0-9]|.

|
But in the paragraph 5.1: Splitting Strings
I find:
|

p = re.compile(r'\W+')
p.split('This is a test, short and sweet, of split().') ['This', 'is', 'a', 'test', 'short', 'and', 'sweet', 'of', 'split', '']
At first I thought a typo:
But on my Python command line:
Python 2.3 (#46, Jul 29 2003, 18:54:32) [MSC v.1200 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information. import re
p = re.compile(r'\W+'); print p <_sre.SRE_Pattern object at 0x0090DC38> p.split('This is a test, short and sweet, of split().') ['This', 'is', 'a', 'test', 'short', 'and', 'sweet', 'of', 'split', ''] p = re.compile(r'\w+'); print p <_sre.SRE_Pattern object at 0x0090D140> p.split('This is a test, short and sweet, of split().') ['', ' ', ' ', ' ', ', ', ' ', ' ', ', ', ' ', '().']

In other word is Python re module not compatible with Perl ?
I also noted that the tools\scripts\redemo.py behaves different than the Python command line ( it is not the only case )
because it matches 'This' when I use \w+ and not when I use \W+
???
Thank you for any comments,

Marcello


||

[William Park]

Marcello Pietrobon <te*****@attglobal.net> wrote:

p = re.compile(r'\W+')
p.split('This is a test, short and sweet, of split().')

['This', 'is', 'a', 'test', 'short', 'and', 'sweet', 'of', 'split', '']

At first I thought a typo:

It's correct. No typo.
In other word is Python re module not compatible with Perl ?

What answer were you expecting in Perl?

--
William Park, Open Geometry Consulting, <op**********@yahoo.ca>
Linux solution for data management and processing.

[stewart]

Marcello Pietrobon wrote:

I also noted that the tools\scripts\redemo.py behaves different than the
Python command line ( it is not the only case )
because it matches 'This' when I use \w+ and not when I use \W+

This doesn't sound like an error to me. \w+ matches all lowercase and
uppercase letters, and numbers, while \W+ matches everything else. So of
course 'This' will be matched by \w+ and not by \W+. It sounds like your
impression was that \w+ matched only lowercase letters, which is not the
case.