Recursively replace characters in a dictionary

Question

How do I change all dots . to underscores (in the dict\'s keys), given an arbitrarily nested dictionary?

What I tried is write two loops, b

Answer 1

You can write a recursive function, like this

from collections.abc import Mapping
def rec_key_replace(obj):
    if isinstance(obj, Mapping):
        return {key.replace('.', '_'): rec_key_replace(val) for key, val in obj.items()}
    return obj

and when you invoke this with the dictionary you have shown in the question, you will get a new dictionary, with the dots in keys replaced with _s

{'delicious_apples': {'green_apples': 2}, 'green_pear': 4, 'brown_muffins': 5}

Explanation

Here, we just check if the current object is an instance of dict and if it is, then we iterate the dictionary, replace the key and call the function recursively. If it is actually not a dictionary, then return it as it is.