如何在字典列表中迭代嵌套字典？

Question

Still new to Python and need a little help here. I've found some answers for iterating through a list of dictionaries but not for nested dictionaries in a list of dictionaries.

Here is the a rough structure of a single dictionary within the dictionary list

[{ 'a':'1',
'b':'2',
'c':'3',
'd':{ 'ab':'12',
      'cd':'34',
      'ef':'56'},
'e':'4',
'f':'etc...'
}]



dict_list = [{ 'a':'1', 'b':'2', 'c':'3', 'd':{ 'ab':'12','cd':'34', 'ef':'56'}, 'e':'4', 'f':'etc...'}, { 'a':'2', 'b':'3', 'c':'4', 'd':{ 'ab':'23','cd':'45', 'ef':'67'}, 'e':'5', 'f':'etcx2...'},{},........,{}]

That's more or less what I am looking at although there are some keys with lists as values instead of a dictionary but I don't think I need to worry about them right now although code that would catch those would be great.

Here is what I have so far which does a great job of iterating through the json and returning all the values for each 'high level' key.

import ujson as json

with open('test.json', 'r') as f:
    json_text = f.read()

dict_list = json.loads(json_text)

for dic in dict_list:
    for val in dic.values():
        print(val)

Here is the first set of values that are returned when that loop runs

1
2
3
{'ab':'12','cd':'34','ef':'56'}
4
etc...

What I need to be able to do pick specific values from the top level and go one level deeper and grab specific values in that nested dictionary and append them to a list(s). I'm sure I am missing a simple solution. Maybe I'm looking at multiple loops?

Answer 1

How about checking for the instance type using isinstance (of course only works for one level deeper). Might not be the best way though

for dic in dict_list:
    for val in dic.values():
        if not isinstance(val, dict):
            print(val)
        else:    
            for val2 in val.values():
                print (val2)

# 1
# 2
# 3
# 12
# 34
# 56
# 4
# etc...
# 2
# 3

Answer 2

Following the ducktype style encouraged with Python, just guess everything has a .values member, and catch it if they do not:

import ujson as json

with open('test.json', 'r') as f:
    json_text = f.read()

dict_list = json.loads(json_text)

for dic in dict_list:
    for val in dic.values():
        try:
            for l2_val in val.values():
                print(l2_val)
        except AttributeError:
            print(val)

Bazingaa's solution would be faster if inner dictionaries are expected to be rare.

Of course, any more "deep" and you would need some recursion probably:

def print_dict(d):
    for val in d.values():
       try:
           print_dict(val)
        except AttributeError:
           print(val)