Assign function arguments to `self`

Question

I've noticed that a common pattern I use is to assign SomeClass.__init__() arguments to self attributes of the same name. Example:

class SomeClass():
    def __init__(self, a, b, c):
        self.a = a
        self.b = b
        self.c = c

In fact it must be a common task for others as well as PyDev has a shortcut for this - if you place the cursor on the parameter list and click Ctrl+1 you're given the option to Assign parameters to attributes which will create that boilerplate code for you.

Is there a different, short and elegant way to perform this assignment?

Answer 1

Decorator magic!!

>>> class SomeClass():
        @ArgsToSelf
        def __init__(a, b=1, c=2, d=4, e=5):
            pass

>>> s=SomeClass(6,b=7,d=8)
>>> print s.a,s.b,s.c,s.d,s.e
6 7 2 8 5

while defining:

>>> import inspect
>>> def ArgsToSelf(f):
    def act(self, *args, **kwargs):
        arg_names,_,_,defaults = inspect.getargspec(f)
        defaults=list(defaults)
        for arg in args:
            setattr(self, arg_names.pop(0),arg)
        for arg_name,arg in kwargs.iteritems():
            setattr(self, arg_name,arg)
            defaults.pop(arg_names.index(arg_name))
            arg_names.remove(arg_name)
        for arg_name,arg in zip(arg_names,defaults):
            setattr(self, arg_name,arg)
        return f(*args, **kwargs)
    return act

Of course you could define this decorator once and use it throughout your project.
Also, This decorator works on any object function, not only __init__.