Hi I'm always been confused with Regex, and I don't understand the responses to the other help threads.
Basically my question is, can i combine
r'^input/?$'
and
r'^input/index.html?$'
into this?
r'^input(/(index.html?)?)?$'
In Django, I get this error:
input() takes exactly 1 argument (3 given)
It only gives the error when it matches correctly, so maybe it's not a regex problem?
Personally, I would prefer not to combine the two regular expressions. I think that having two url patterns,
url(r'^input/?$', input, name="input"),
url(r'^input/index.html?$', input),
is more readable than one.
However, if you do want to combine the two, you can use non-capturing parentheses:
r'^input(?:/(?:index.html?)?)?$'
A quick example might help explain:
>>> import re
>>> # first try the regex with capturing parentheses
>>> capturing=r'^input(/(index.html?)?)?$'
>>> # Django passes the two matching strings to the input view, causing the type error
>>> print re.match(capturing, "input/index.html").groups()
('/index.html', 'index.html')
>>> # repeat with non capturing parentheses
>>> non_capturing=r'^input(?:/(?:index.html?)?)?$'
>>> print re.match(non_capturing, "input/index.html").groups()
()
See the Regular Expression Advanced Syntax Reference page for more info.
If you use this in your urlpatterns you don't need to write ? symbol because everything that comes after that you can parse in your view function. And the request to /input/index.html?param=2 will be correctly processed with r'^input/index.html$' regex. Then in the view function you can obtain parameters like so:
def my_view(request):
param = request.GET.get('param', 'default_value')
Find more info here: https://docs.djangoproject.com/en/1.9/topics/http/urls/
