Code for walking a nested dictionary in python and turning it into a flat dictionary with dotted key names

linearize_dict.py

def linearize_dict(dct, prefix=None, part_sep="."):
    """Walk a nested dict, and flatten it"""
    linearized = {}
    for key, value in dct.items():
        # Ensure key doesn't already contain part_sep
        if part_sep in key:
            raise Exception("Part sep '%s' exists in key. Use a different part sep")
        # Create prefixed version of this key if needed
        if prefix == None:
            prefixed_key = key
        else:
            prefixed_key = "%s%s%s"%(prefix, part_sep, key)
        # Decend into dict if needed
        if type(value) == dict:
            linearized.update(linearize_dict(value, prefixed_key, part_sep))
        else:
            linearized[prefixed_key] = value
    return linearized


"""
nested_dict = {
    "fruits": {"apple": True, "pear": True, "tomato": False},
    "author_states": {"willing_to_die_on_this_hill": True}
}

linearize_dict(nested_dict) -> {"fruits.apple" : True, 
                                "fruits.pear": True,
                                "fruits.tomato": False,
                                "author_states.willing_to_die_on_this_hill": True
                                }
"""