Convert python dictionary of many levels to single level dictionary with dot notation keys. This can be useful when writing to a format that requires a flat object/dictionary, such as CSV.

script.py

def dict_dot_notation(d, path=[]):
    d2 = {}
    for k, v in d.items():
        k_path = path + [str(k)]
        k_formatted = ".".join(k_path)

        if isinstance(v, dict):
            # merge in dict with recursive call
            d2 = {**d2, **dict_dot_notation(v, path=k_path)}
        elif isinstance(v, list) or isinstance(v, tuple):
            # handle list / tuple as comma separated strings
            d2[k_formatted] = ",".join([str(i) for i in v])
        else:
            # force anything else to string representation
            d2[k_formatted] = str(v)
    return d2


d = {
    'a': 'A',
    'b': {
        'c': 'C',
        'd': {
            'e': 'E',
            'f': [0, 1, 2]
        },
        'g': [3, 4, 5],
        'h': '',
        'i': True
    },
    'j': False
}
import json
print(json.dumps(dict_dot_notation(d), indent=2))

# {
#   "a": "A",
#   "b.c": "C",
#   "b.d.e": "E",
#   "b.d.f": "0,1,2",
#   "b.g": "3,4,5",
#   "b.h": "",
#   "b.i": "True",
#   "j": "False"
# }