Python: Apply function to values in nested dictionary

Question

I have an arbitrarily deep set of nested dictionary:

x = {\'a\': 1, \'b\': {\'c\': 6, \'d\': 7, \'g\': {\'h\': 3, \'i\': 9}}, \'e\': {\'f\': 3}}

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Answer 1

Just to expand on vaultah's answer, if one of your elements can be a list, and you'd like to handle those too:

import collections

def map_nested_dicts_modify(ob, func):
for k, v in ob.iteritems():
    if isinstance(v, collections.Mapping):
        map_nested_dicts_modify(v, func)
    elif isinstance(v, list):
        ob[k] = map(func, v)
    else:
        ob[k] = func(v)