Question

I have main dictionary.

mainDict = {'count': 10, 'a': {'abc': {'additional': 0, 'missing': 0, 'changed': 0}}}

Now i have new dictionary with same keys as in mainDict, called this dictionary as b with different values.

b = {'count': 20, 'a': {'abc': {'additional': 10, 'missing': 10, 'changed': 10}}}

I want to update(addition operation) the values of keys in main dictionary so i do..

mainDict = {'count': mainDict['count'] + b['count'], 'a': }

I am stuck at updating values of key a. If i use mainDict.update(b) then it will replace previous values. Any efficient solution??

The final output required is:

mainDict = {'count': 30, 'a': {'abc': {'additional': 10, 'missing': 10, 'changed': 10}}}

Thanks

Answer 1

def recursive_dict_sum_helper(v1, v2):
    # "add" two values: if they can be added with '+', then do so,
    # otherwise expect dictionaries and treat them appropriately.
    try: return v1 + v2
    except: return recursive_dict_sum(v1, v2)

def recursive_dict_sum(d1, d2):
    # Recursively produce the new key-value pair for each
    # original key-value pair, and make a dict with the results.
    return dict(
        (k, recursive_dict_sum_helper(v, d2[k]))
        for (k, v) in d1.items()
    )

mainDict = recursive_dict_sum(mainDict, b)