Question

Is is possible to access the arguments which were passed to __init__, without explicitly having to store them?

e.g.

class thing(object):
  def __init__(self, name, data):
    pass # do something useful here

t = thing('test', [1,2,3,])
print t.__args__ # doesn't exist

>> ('test', [1,2,3])

The use-case for this is creating a super-class which can automatically store the arguments used to create an instance of a class derived from it, without having to pass all the arguments explicitly to the super’s __init__. Maybe there’s an easier way to do it!

Answer 1

No, you have to store them. Otherwise they are gone after __init__() returns, as all local variables.

If you don’t want to pass all arguments on explicitly, you can use **kwargs:

class Base(object):
    def __init__(self, name, data):
        # store name and data

class Derived(Base):
    def __init__(self, **kwargs):
        Base.__init__(self, **kwargs)

Derived(name="Peter", data=42)