Are there any 'gotchas' with this Python pattern?

Question

Here's the pattern I'm thinking of using:

class Dicty(dict): 
    def __init__(self): 
         self.__dict__ = self 

d = Dicty()
d.foo = 'bar' 
print d['foo']
>>> bar 
d['foo'] = 'baz'
print d.foo
>>> 'baz'

Generally, I prefer the semantics of object attribute access over dict get/set access, but there are some circumstances where dict-like access is required (for example, d['foo-bar'] = 'baz') and I'd prefer not to have special getter setter methods for these cases, so thus, the dual behavior of dict & object at the same time with shared attributes.

Are there any gotchas with the above pattern?

Answer 1

Here's a less "hacky" way to achieve the same effect:

class Dicty(dict):
    def __getattr__(self, key):
        return self[key]

    def __setattr__(self, key, value):
        self[key] = value

I think that your way may work fine as well, but setting the __dict__ attribute like that seems a bit iffy style-wise, and is bound to raise some questions if anyone else ends up reading your code.

Answer 2

Don't set self.__dict__. Call __init__(self, *args, **kwargs) on the superclass. Also, dict inherits from object so you don't need to specify it.