Dealing with scope in a recursive Python function

I have a JSON input file that looks like this:

{"nodes": [
    {"properties": {
        "id": "rootNode",
        "name": "Bertina Dunmore"},
      "nodes": [
        {"properties": {
            "id": 1,
            "name": "Gwenneth Rylett",
            "parent_id": "rootNode"},
          "nodes": [
            {"properties": {
                "id": 11,
                "name": "Joell Waye",
                "parent_id": 1}},
            {"properties": {
                "id": 12,
                "name": "Stan Willcox",
                "parent_id": 1}}]},
        {"properties": {
            "id": 2,
            "name": "Delbert Dukesbury",
            "parent_id": "rootNode"},
          "nodes": [
            {"properties": {
                "id": 21,
                "name": "Cecil McKeever",
                "parent_id": 2}},
            {"properties": {
                "id": 22,
                "name": "Joy Obee",
                "parent_id": 2}}]}]}]}

I want to get the nested properties dictionaries into a (flat) list of dictionaries. Creating a recursive function that will read this dictionaries is easy:

def get_node(nodes):
    for node in nodes:
        print(node['properties'])
        if 'nodes' in node.keys():
            get_node(node['nodes'])

Now, I’m struggling to append these to a single list:

def get_node(nodes):
    prop_list = []
    for node in nodes:
        print(node['properties'])
        prop_list.append(node['properties'])
        if 'nodes' in node.keys():
            get_node(node['nodes'])
    return prop_list

This returns [{'id': 'rootNode', 'name': 'Bertina Dunmore'}], even though all properties dictionaries are printed. I suspect that this is because I’m not handling the function scope properly.

Can someone please help me get my head around this?

>Solution :

You need to combine the prop_list returned by the recursive call with the prop_list in the current scope. For example,

def get_node(nodes):
    prop_list = []
    for node in nodes:
        print(node['properties'])
        prop_list.append(node['properties'])
        if 'nodes' in node.keys():
            prop_list.extend(get_node(node['nodes']))
    return prop_list