nested_dict.py

tree_already_apended = []
tree_childs_key = 'childs'
data = [
    dict(
        id=1,
        parent=None
    ),
    dict(
        id=2,
        parent=1
    ),
    dict(
        id=3,
        parent=2
    ),
    dict(
        id=4,
        parent=3
    ),
    dict(
        id=5,
        parent=34243
    ),
    dict(
        id=6,
        parent=5
    ),
    dict(
        id=7,
        parent=6
    ),
    dict(
        id=8,
        parent=7
    ),
    dict(
        id=9,
        parent=8
    ),
    dict(
        id=10,
        parent=9
    ),
    dict(
        id=12,
        parent=10
    ),
    dict(
        id=13,
        parent=12
    )
]


def build_tree_wrap(items, root=None):
    if not root:
        keys = []
        for item in items:
            keys.append(item['parent'])
        root = min(keys)
    tree = build_tree(items, root)
    if len(tree_already_apended) != len(items):
        for item in items:
            if item['id'] not in tree_already_apended:
                tree.append(
                    build_tree_item(item, items)
                )
    return tree


def build_tree(items, root):
    tree = []
    for item in items:
        if item['id'] in tree_already_apended:
            continue
        if item['parent'] == root:
            tree.append(build_tree_item(item, items))
    return tree


def build_tree_item(item, items):
    processed = dict(name='Test' + str(item['id']))
    processed[tree_childs_key] = build_tree(items, item['id'])
    processed['leaf'] = False if processed[tree_childs_key] else True
    tree_already_apended.append(item['id'])
    return processed


def printer(tree, level=0):
    for item in tree:
        print ' '*level*2 + item['name']
        if 'childs' in item:
            printer(item['childs'], level + 1)


tree = build_tree_wrap(data)
printer(tree)