Recursively build a path from a python dictionary

January 30, 2024

I have the following python dictionary:

a = {'name': 'Kestral',
     'children': [
         {'name': 'Burtree Lane',
          'children': [
              {'name': 'ARCHIVE', 
               'children': []},
              {'name': 'Development',
               'children': [
                   {'name': 'Fee Proposals',
                    'children': []}]}]}]}

and i’m trying to write a recursive function to produce the following dictionary:

{'name': 'Kestral',
     'folder': 'Kestral',
     'children': [
         {'name': 'Burtree Lane',
          'folder': 'Kestral/Burtree Lane',
          'children': [
              {'name': 'ARCHIVE',
               'folder': 'Kestral/Burtree Lane/ARCHIVE',
               'children': []},
              {'name': 'Development',
               'folder': 'Kestral/Burtree Lane/Development',
               'children': [
                   {'name': 'Fee Proposals',
                    'folder': 'Kestral/Burtree Lane/Development',
                    'children': []}]}]}]}

This is my python code:

def build_structured_dict(data, parent_path="/"):
  new_dict = {
      "name": data["name"],
      "folder": f"{parent_path}{data['name']}" if parent_path else data["name"],
      "children": [],
  }
  for child in data["children"]:
    child_path = f"{parent_path}{data['name']}" if parent_path else ""
    new_dict["children"].append(build_structured_dict(child, f"{child_path}/{child['name']}"))
  return new_dict

But this returns:

{'name': 'Kestral',
     'folder': '/Kestral',
     'children': [{
         'name': 'Burtree Lane',
         'folder': '/Kestral/Burtree LaneBurtree Lane',
         'children': [{
             'name': 'ARCHIVE',
             'folder': '/Kestral/Burtree LaneBurtree Lane/ARCHIVEARCHIVE',
             'children': []},
            {'name': 'Development',
             'folder': '/Kestral/Burtree LaneBurtree Lane/DevelopmentDevelopment',
             'children': [{
                 'name': 'Fee Proposals',
                 'folder': '/Kestral/Burtree LaneBurtree Lane/DevelopmentDevelopment/Fee ProposalsFee Proposals',
                 'children': []}]}]}]}

Can someone help me in removing these duplicates?

>Solution :

You’re concatenating the "name" attribute both as argument to the recursive call (child["name"]) as in that recursive execution itself data["name"], causing the duplication.

Here is a correction to your code, which keeps the initial slash which you also produced in your code:

def build_structured_dict(data, parent_path="/"):
  path = f"{parent_path}{data['name']}"
  new_dict = {
      "name": data["name"],
      "folder": path,
      "children": [],
  }
  for child in data["children"]:
    new_dict["children"].append(build_structured_dict(child, path + "/"))
  return new_dict

If you don’t want the initial slash (as depicted in your desired output), then set the default value for the second parameter to the empty string.