python - Find a string as value in a dictionary of dictionaries and return its key -

i need write function doing following work

find string value in dictionary of dictionaries , return key (1st key if found in main dictionary, 2nd key if found in sub dictionary).

source code

here function try implement, works incorrect i can't find answer of how convert list dictionary in case following error occurs

for v, k in l: valueerror: need more 1 value unpack

def getkeyfromdictbyvalue(self, dictionary, value_to_find):     """"""      key_list = [k (k, v) in dictionary.items() if v == value_to_find]     if key_list.__len__() not 0:         return key_list[0]     else:         l = [s s in dictionary.values() if  ":" in str(s)]         d = defaultdict(list)         v, k in l:             d[k].append(v)          print d  dict = {'a': {'a1': 'a2'}, "aa": "aa1", 'aaa': {'aaa1': 'aaa2'}} print getkeyfromdictbyvalue(dict, "a2") 

i must on python 2.5

you created list of only dictionary values, try loop on if contains both keys , values of dictionaries. perhaps wanted loop on each matched dictionary?

l = [v v in dictionary.values() if  ":" in str(v)] d = defaultdict(list) subdict in l:     k, v in subdict.items(): 

i'd instead flatten structure:

def flatten(dictionary):     key, value in dictionary.iteritems():         if isinstance(value, dict):             # recurse             res in flatten(value):                 yield res         else:             yield key, value 

then search:

def getkeyfromdictbyvalue(self, dictionary, value_to_find):     key, value in flatten(dictionary):         if value == value_to_find:             return key 

demo:

>>> sample = {'a': {'a1': 'a2'}, "aa": "aa1", 'aaa': {'aaa1': 'aaa2'}} >>> getkeyfromdictbyvalue(none, sample, "a2") 'a1'