Python 获取嵌套字典中值的键

Question

Let's say I have a dictionary called my_dic:

my_dict = {'a': {'spam': {'foo': None, 'bar': None, 'baz': None},'eggs': None}, 'b': {'ham': None}}

Then if I input spam , it should return a , and if I input bar it should return spam . If I input b , it should return None . Basically getting the parent of the dictionary.

How would I go about doing this?

Answer 1

A simple recursive function, which returns the current key if needle in v is true; needle in v simply testing if the key exists in the associated value:

my_dict = {'a': {'spam': {'foo': None, 'bar': None, 'baz': None},'eggs': None}, 'b': {'ham': None}}

def get_parent_key(d: dict, needle: str):
    for k, v in d.items():
        if isinstance(v, dict):
            if needle in v:
                return k
            
            if found := get_parent_key(v, needle):
                return found
                
print(get_parent_key(my_dict, 'bar'))