List to nested dictionary
<p>I have list of levels like </p>

<pre><code>levels = [["A", "B", "C", "D"], ["A", "B"], ["A", "B", "X"]]
</code></pre>

<p>In response nested dictionary should appear like</p>

<pre><code>    {
    "name": "A", 
    "parent": -1, 
    "children": [
        {
            "name": "B", 
            "parent": "A", 
            "children": [
                {
                    "name": "C", 
                    "parent": "B", 
                    "children": [
                        {
                            "name": "D", 
                            "parent": "C", 
                        }
                    ], 

                }, 
                {
                    "name": "X", 
                    "parent": "B"
                }
            ], 

        }
    ]
}
</code></pre>

<p>I know I am missing something in recursion loop.</p>

<p>So far this is my code</p>

<pre><code>import csv
import json

class AutoVivification(dict):
    """Implementation of perl's autovivification feature."""
    def __getitem__(self, item):
        try:
            return dict.__getitem__(self, item)
        except KeyError:
            value = self[item] = type(self)()
            return value

def master_tree(data, payload, parent = -1):
    if len(data) == 1:
        if data[0] not in payload['name']:
            payload = {'name':data[0], "parent": parent}
    else:
        if data[0] in payload['name']:
            for k in payload['children']:
                master_tree(data[1:], k, data[0])
        else:
            payload = {'name': data[1], "parent": data[0], 'children':[master_tree(data[1:], payload, data[0])]}

    return payload


payload = AutoVivification()
payload = master_tree(["A", "B", "X"], payload)
payload = master_tree(["A", "B", "C", "D"], payload)

print json.dumps(payload, indent=4)
</code></pre>

<p>Problem occurs when same structure is repeated. Like A->B->C->D is already present from 1st iteration and when A->B is passed again it should ideally skip it and in last case it should add just X node under B</p>

<pre><code>import csv
import json

class AutoVivification(dict):
    """Implementation of perl's autovivification feature."""
    def __getitem__(self, item):
        try:
            return dict.__getitem__(self, item)
        except KeyError:
            value = self[item] = type(self)()
            return value

def master_tree(data, payload, parent = -1):
    if len(data) == 1:
        if data[0] not in payload['name']:
            payload = {'name':data[0], "parent": parent}
    else:
        if 'name' in payload and data[0] in payload['name']:
            get_list = []
            for k in payload['children']:
                get_list.append(k['name'])
            if data[1] in get_list:
                master_tree(data[1:], k, data[0])            
            else:
                payload['children'].append(master_tree(data[1:], {'name':data[0], "parent": parent}, data[0]))

        else:
            payload = {'name': data[0], "parent": parent, 'children':[master_tree(data[1:], payload, data[0])]}

    return payload


payload = AutoVivification()
payload = master_tree(["A", "B", "X"], payload)
payload = master_tree(["A", "B", "C", "D"], payload)
payload = master_tree(["A", "B", "Q"], payload)


print json.dumps(payload, indent=4)
</code></pre>

python tree hierarchy