How to understand the Url patterns in django url.py

Question

How to understand the Url patterns for eg. (?P<slug>[-\w]+)/$ in django url.py

I was tempted to just recommend the [manual](https://docs.djangoproject.com/en/dev/topics/http/urls/). — Jonas Schäfer, Apr 18 '12 at 05:02
It's a regular expression. Read up on http://docs.python.org/library/re.html to understand more. — agf, Apr 18 '12 at 05:15

score 4 · Answer 1 · edited Apr 18 '12 at 12:04

4

This url: (?P<slug>[-\w]+)/$

Says that you are passing a variable to your view called slug could be any digits or letters and -

your view is like this:

def my_view(request, slug):
   ....

hope it helps...

edited Apr 18 '12 at 12:04

olofom

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answered Apr 18 '12 at 05:16

pahko

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This doesn't explain where those "digits or letters" come from. – agf Apr 18 '12 at 05:21

score 0 · Answer 2 · answered Apr 18 '12 at 05:07

0

First Mastering Regular Expressions, then 7.2.1 - Regular Expression Syntax

answered Apr 18 '12 at 05:07

Burhan Khalid

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Don't post just links as answers. Either add details / examples or post it as a comment. – agf Apr 18 '12 at 05:15
I totally agree with agf even though the question of Gopi was not wise. Regular expressions is a huge field where just a link does not help. – Timo Jun 01 '14 at 05:39

score 0 · Answer 3 · edited Apr 18 '12 at 10:09

0

Note that slug fields might also include digits (not just letters and the dash), so you want to alter it to say something like:

 SLUG = '(?P<slug>[\w\d-]+)'

I hope this helpful to you...

edited Apr 18 '12 at 10:09

DaveShaw

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answered Apr 18 '12 at 05:10

Thanag Vignesh Raja T

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This doesn't answer the question. He was asking how to interpret them, not how to change them to do something. – agf Apr 18 '12 at 05:16

score 0 · Answer 4 · answered Apr 18 '12 at 05:45

I think it is not a valid regex pattern. "[-\w]+" will get "word and -", something like "a-b9-c-" or "---" (?P...) is a "Named Group". If you don't give its name, python (mine is 2.7) will raise error.

>>> m = re.match("(?P<e>[-\w]+)/$", "a-b-c-/")
>>> m.group('e')
'a-b-c-'
>>> m = re.match("(?P[-\w]+)/$", "a-b-c-/")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/re.py", line 137, in match
    return _compile(pattern, flags).match(string)
  File "/usr/lib/python2.7/re.py", line 244, in _compile
    raise error, v # invalid expression
sre_constants.error: unknown specifier: ?P[

But it has the group specified. It *is* valid. (I presume you were looking at the non-escaped version which I fixed three-quarters of an hour before you posted this.) — Chris Morgan, Apr 19 '12 at 05:05

How to understand the Url patterns in django url.py

4 Answers4