Nested defaultdict of defaultdict

Question

Is there a way to make a defaultdict also be the default for the defaultdict? (i.e. infinite-level recursive defaultdict?)

I want to be able to do:

x         


        

Answer 1

@nucklehead's response can be extended to handle arrays in JSON as well:

def nested_dict(existing=None, **kwargs):
    if existing is None:
        existing = defaultdict()
    if isinstance(existing, list):
        existing = [nested_dict(val) for val in existing]
    if not isinstance(existing, dict):
        return existing
    existing = {key: nested_dict(val) for key, val in existing.items()}
    return defaultdict(nested_dict, existing, **kwargs)