Convert nested dictionary to tree python

I have a large RDF file containing about 600,000 records of Wikidata taxonomy. From this file, I am only interested in subclassOf relations [predicate], thus, I ignore all the other statements keeping only "subclassOf" statements. The statement is like: a is a subclassOf b, b is a subclassOf c Like that c is a parent of b and b is a parent of a. And any parent can have many children. I want to build hierarchical tree using this taxonomy. I have checked this thread and it almost solved my problem. Recursively creating a tree hierarchy without using class/object However, with this, I am getting tree in dictionary which I want to convert into tree data-structure. Following is what I have tried:

data = [['a','x'], ['b','x'], ['c','x'], ['x','y'], ['t','y'], ['y','p'], ['p','q']]

roots = set[]
mapping = {}
for child,parent in data:        
    childitem = mapping.get[child,None]
    if childitem is None:
        childitem =  {}
        mapping[child] = childitem
    else:
        roots.discard[child]
    parentitem = mapping.get[parent,None]
    if parentitem is None:
        mapping[parent] = {child:childitem}
        roots.add[parent]
    else:
        parentitem[child] = childitem

for root in roots:
    print[mapping[root]]

tree = { id : mapping[id] for id in roots }
print[tree]

Output of tree looks as below:

{'q': {'p': {'y': {'t': {}, 'x': {'c': {}, 'b': {}, 'a': {}}}}}}

I want to convert this dictionary to tree. So e.g. when I say print[mapping['y']], it should give me Node y i.e.

q
├── p
    └── y

currently, if I say mapping['y'], it gives me subtree rooted at y. I think there is some easy solution for this, but I am not able to understand it. I have found this link as well //gist.github.com/hrldcpr/2012250 to convert dictionary into tree, but not sure how to use it in my case. Alernatively, if anyone knows to directly built a tree from the RDF data that I had given above, then it will be most welcome. Probably python's anytree API will solve my issue.

Given a nested dictionary, the task is to convert this dictionary into a flattened dictionary where the key is separated by ‘_’ in case of the nested key to be started.

Given below are a few methods to solve the above task.

Method #1: Using Naive Approach 

Python3

def flatten_dict[dd, separator ='_', prefix ='']:

    return { prefix + separator + k if prefix else k : v

             for kk, vv in dd.items[]

             for k, v in flatten_dict[vv, separator, kk].items[]

             } if isinstance[dd, dict] else { prefix : dd }

ini_dict = {'geeks': {'Geeks': {'for': 7}},

            'for': {'geeks': {'Geeks': 3}},

            'Geeks': {'for': {'for': 1, 'geeks': 4}}}

print ["initial_dictionary", str[ini_dict]]

print ["final_dictionary", str[flatten_dict[ini_dict]]]

Output: 
initial_dictionary {‘geeks’: {‘Geeks’: {‘for’: 7}}, ‘Geeks’: {‘for’: {‘geeks’: 4, ‘for’: 1}}, ‘for’: {‘geeks’: {‘Geeks’: 3}}} 
final_dictionary {‘Geeks_for_for’: 1, ‘geeks_Geeks_for’: 7, ‘for_geeks_Geeks’: 3, ‘Geeks_for_geeks’: 4} 
 

Method #2: Using mutuableMapping 

Python3

from collections import MutableMapping

def convert_flatten[d, parent_key ='', sep ='_']:

    items = []

    for k, v in d.items[]:

        new_key = parent_key + sep + k if parent_key else k

        if isinstance[v, MutableMapping]:

            items.extend[convert_flatten[v, new_key, sep = sep].items[]]

        else:

            items.append[[new_key, v]]

    return dict[items]

ini_dict = {'geeks': {'Geeks': {'for': 7}},

            'for': {'geeks': {'Geeks': 3}},

            'Geeks': {'for': {'for': 1, 'geeks': 4}}}

print ["initial_dictionary", str[ini_dict]]

print ["final_dictionary", str[convert_flatten[ini_dict]]]

Output: 
initial_dictionary {‘Geeks’: {‘for’: {‘for’: 1, ‘geeks’: 4}}, ‘for’: {‘geeks’: {‘Geeks’: 3}}, ‘geeks’: {‘Geeks’: {‘for’: 7}}} 
final_dictionary {‘Geeks_for_geeks’: 4, ‘for_geeks_Geeks’: 3, ‘geeks_Geeks_for’: 7, ‘Geeks_for_for’: 1} 
 

Method #3: Using Python Generators  

Python3

my_map = {"a" : 1,

        "b" : {

            "c": 2,

            "d": 3,

            "e": {

                "f":4,

                6:"a",

                5:{"g" : 6},

                "l":[1,"two"]

            }

        }}

ini_dict = {'geeks': {'Geeks': {'for': 7}},

            'for': {'geeks': {'Geeks': 3}},

            'Geeks': {'for': {'for': 1, 'geeks': 4}}}

def flatten_dict[pyobj, keystring='']:

    if type[pyobj] == dict:

        keystring = keystring + '_' if keystring else keystring

        for k in pyobj:

            yield from flatten_dict[pyobj[k], keystring + str[k]]

    else:

        yield keystring, pyobj

print["Input : %s\nOutput : %s\n\n" %

     [my_map, { k:v for k,v in flatten_dict[my_map] }]]

print["Input : %s\nOutput : %s\n\n" %

     [ini_dict, { k:v for k,v in flatten_dict[ini_dict] }]]

Output: 
initial_dictionary {‘for’: {‘geeks’: {‘Geeks’: 3}}, ‘geeks’: {‘Geeks’: {‘for’: 7}}, ‘Geeks’: {‘for’: {‘for’: 1, ‘geeks’: 4}}} 
final_dictionary {‘Geeks_for_geeks’: 4, ‘for_geeks_Geeks’: 3, ‘Geeks_for_for’: 1, ‘geeks_Geeks_for’: 7} 
 

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