On 6/4/06, David Robinson <[EMAIL PROTECTED]> wrote:
> Really, I've tried looking this one up myself (you wouldn't believe how
> many questions I *haven't* had to ask... (thanks for well-written docs
> everyone)). It seems almost obvious, but I am proving to be just dense
> enough to not get what is this "kwarg".
It's a shorthand for 'keyword argument'.
Minor OT explanation, since it's a useful Python concept:
Arguments to a function can be either positional (where the function
figures out which argument is which based on the order they come in),
or keyword (where they're pass as name/value pairs, like
"Poll.objects.get(pk=1)" -- "pk=1" is a keyword argument).
Python provides shortcuts for passing lots of these, and you'll see
them used all over the place in Django. For example, you could do
my_func('foo', 'bar', 'baz')
and 'foo', 'bar' and 'baz' would be positional arguments. But you can
also build up a list, and pass it directly to a function, like so:
my_args = ['foo', 'bar', 'baz']
my_func(*my_args)
The asterisk tells Python "take this list and treat it as the
positional arguments". Often when you don't know in advance what the
arguments are giong to be, this is a lot easier. The same is true of
keyword arguments; instead of
my_func(foo=bar, baz=quux)
you can build a dictionary and pass it to the function:
my_kwargs = {'foo': 'bar', 'baz': 'quux'}
my_func(**my_kwargs)
The double-asterisk tells Python "take this dictionary and treat it as
the keyword arguments".
That's why there are lots of places in Django where you'll see things like
some_func(*args, **kwargs)
What's happened is that the positional arguments have been put into a
list called 'args' as they were figured out, and the keyword arguments
into a dictionary called 'kwargs' -- the names serve as a reminder of
what they're for -- and then the list and the dictionary are handed
off to the function.
--
"May the forces of evil become confused on the way to your house."
-- George Carlin
--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups
"Django users" group.
To post to this group, send email to django-users@googlegroups.com
To unsubscribe from this group, send email to [EMAIL PROTECTED]
For more options, visit this group at
http://groups.google.com/group/django-users
-~----------~----~----~----~------~----~------~--~---
