three methods, two to float-up the path to a key or value and one that given a dictionary and a tuple of keys/indices returns the value.

find_key_or_value_in_nested_dict.py

#python 3
# three methods, two to float-up the path to a key or value and one that given a convoluted nested dictionary and a tuple of keys/indices returns the value.
# float_key(dictionary,key)
# float_value(dictionary,key)
# get_value(dictionary,(keys/indices list))
# great for entrez, Uniprot, PDB XML dictionaries
# NB. works for dict and list like objects

import collections

def float_key(dex, key):
    try:
        if dex is str:
            return False
        elif isinstance(dex,collections.Mapping): #quacks like a dictionary
            if key in dex:
                return [key]
            else:
                for clavis in dex:
                    verdict = float_key(dex[clavis],key)
                    if verdict:
                        return [clavis, *verdict]
        elif isinstance(dex,collections.Iterable): #quacks like a list
            for i in range(len(dex)):
                verdict=float_key(dex[i], key)
                if verdict is not False:
                    return [i,*verdict]
        else:
            print('Unknown type',type(dex))
        return False
    except RecursionError:
        return False

def float_value(dex, value):
    try:
        if dex is str:
            return False
        elif isinstance(dex, collections.Mapping):  # quacks like a dictionary
            for clavis in dex:
                if value == dex[clavis]:
                    return [clavis]
                else:
                    verdict = float_value(dex[clavis], value)
                    if verdict:
                        return [clavis, *verdict]
        elif isinstance(dex, collections.Iterable):  # quacks like a list
            for i in range(len(dex)):
                if value == dex[i]:
                    return [i]
                else:
                    verdict = float_value(dex[i], value)
                    if verdict is not False:
                        return [i, *verdict]
        else:
            print('Unknown type', type(dex))
        return False
    except RecursionError:
        return False
        
def get_value(dex, fields):
    try:
        inner = dex
        for entry in fields:
            inner = inner[entry]
        return inner
    except:
        return None