work with nested dicts

nested_dicts.py

import collections
import os
import re
from copy import deepcopy
from functools import reduce
from operator import getitem


def update_nested_dicts(base_dct, new_dct, only_existed_keys=False):
    # IN[]:
    # f1 = {'1': {'a': 'f1_1a', 'b': 'f1_1b', 'd': 'f1_1c'}, '2': 'f1_2', '3': 'f1_3'}
    # f2 = {'1': {'a': 'f2_1a', 'b': 'f2_1b', 'c': 'f2_1c'}, '2': 'f2_2', '4': 'f2_4'}
    # c1 = update_nested_dicts(f1, f2)
    # c2 = update_nested_dicts(f1, f2, None)
    # c3 = update_nested_dicts(f1, f2, False)
    # c4 = update_nested_dicts(f1, f2, True)
    # print(f"c1={c1}\nc4={c4}\n{c1 == c2, c2 == c3, c3 != c4}")
    #
    # Out[]:
    # c1={'1': {'a': 'f2_1a', 'b': 'f2_1b', 'd': 'f1_1c', 'c': 'f2_1c'}, '2': 'f2_2', '3': 'f1_3', '4': 'f2_4'}
    # c4={'1': {'a': 'f2_1a', 'b': 'f2_1b', 'd': 'f1_1c'}, '2': 'f2_2', '3': 'f1_3'}
    # (True, True, True)

    if base_dct is None:
        base_dct = {}
    if not (new_dct and isinstance(new_dct, dict)):
        return deepcopy(base_dct)
    if not (base_dct and isinstance(base_dct, dict)):
        return deepcopy(new_dct)

    rtn_dct = deepcopy(base_dct)
    if only_existed_keys is True:
        new_dct = {key: new_dct[key] for key in set(rtn_dct).intersection(set(new_dct))}

    rtn_dct.update({
        key: update_nested_dicts(rtn_dct[key], new_dct[key], only_existed_keys=only_existed_keys)
        if isinstance(rtn_dct.get(key), dict) and isinstance(new_dct[key], dict)
        else deepcopy(new_dct[key])
        for key in new_dct.keys()
    })
    return rtn_dct

  
  def get_nested_item(data, keys):
    try:
        return reduce(getitem, filter(None, keys), data)
    except:
        return None


def set_nested_item(data, keys, value):
    try:
        for key in keys[:-1]:
            data = data.setdefault(key, {})
        data[keys[-1]] = deepcopy(value)
    finally:
        return data