Recursively replace characters from keys of a Python dictionary

replace_dictionary_key_chars.py

################################################################################
# The following demonstrates how to recursively replace specific characters 
# from within keys of a nested dictionary or JSON object, leaving values as is.
################################################################################

# Given the following example dictionary with characters needing to be replaced:
example = [
    {
        "_id": "5ae2821988fc6a16af73aeb0",
        "index": 0,
        "keys_with_invalid_characters": [
            {
                "\tFour\t\tTabs\t": "\t\t\t\t",
                "C,o,m,m,a,s": ",,,,",
                "C{u}r{l}y{B}r{a}c{k}e{t}s": "{}{}",
                "New\nLine\ns": "\n\n\n\n",
                "P(a)r(e)n(t)h(e)s(e)s": "()()",
                "S p a c e s": "    ",
                "S;e;m;i;c;o;l;o;n;s": ";;;;"
            }
        ]
    }
]

# Recursive function
def replace_keys(obj, old, new):
    if isinstance(obj, dict):
        return {k.replace(old, new): replace_keys(v, old, new) for k, v in obj.items()}
    elif isinstance(obj, list):
        return [replace_keys(i, old, new) for i in obj]
    else:
        return obj

# Replace invalid characters within keys with empty string
invalid_characters = ' ,;{}()\n\t='
for char in invalid_characters:
    example = replace_keys(example, char, '')

# Results
import json
print(json.dumps(example, indent=4, sort_keys=True))

[
    {
        "_id": "5ae2821988fc6a16af73aeb0",
        "index": 0,
        "keys_with_invalid_characters": [
            {
                "Commas": ",,,,",
                "CurlyBrackets": "{}{}",
                "FourTabs": "\t\t\t\t",
                "NewLines": "\n\n\n\n",
                "Parentheses": "()()",
                "Semicolons": ";;;;",
                "Spaces": "    "
            }
        ]
    }
]