Convert nested Python dict to object?

Question

I\'m searching for an elegant way to get data using attribute access on a dict with some nested dicts and lists (i.e. javascript-style object syntax).

For example:

Answer 1

How about this:

from functools import partial
d2o=partial(type, "d2o", ())

This can then be used like this:

>>> o=d2o({"a" : 5, "b" : 3})
>>> print o.a
5
>>> print o.b
3

Answer 2

Surprisingly no one has mentioned Bunch. This library is exclusively meant to provide attribute style access to dict objects and does exactly what the OP wants. A demonstration:

>>> from bunch import bunchify
>>> d = {'a': 1, 'b': {'c': 2}, 'd': ["hi", {'foo': "bar"}]}
>>> x = bunchify(d)
>>> x.a
1
>>> x.b.c
2
>>> x.d[1].foo
'bar'

A Python 3 library is available at https://github.com/Infinidat/munch - Credit goes to codyzu

Answer 3

class Struct(object):
    """Comment removed"""
    def __init__(self, data):
        for name, value in data.iteritems():
            setattr(self, name, self._wrap(value))

    def _wrap(self, value):
        if isinstance(value, (tuple, list, set, frozenset)): 
            return type(value)([self._wrap(v) for v in value])
        else:
            return Struct(value) if isinstance(value, dict) else value

Can be used with any sequence/dict/value structure of any depth.

Answer 4

I stumbled upon the case I needed to recursively convert a list of dicts to list of objects, so based on Roberto's snippet here what did the work for me:

def dict2obj(d):
    if isinstance(d, dict):
        n = {}
        for item in d:
            if isinstance(d[item], dict):
                n[item] = dict2obj(d[item])
            elif isinstance(d[item], (list, tuple)):
                n[item] = [dict2obj(elem) for elem in d[item]]
            else:
                n[item] = d[item]
        return type('obj_from_dict', (object,), n)
    elif isinstance(d, (list, tuple,)):
        l = []
        for item in d:
            l.append(dict2obj(item))
        return l
    else:
        return d

Note that any tuple will be converted to its list equivalent, for obvious reasons.

Hope this helps someone as much as all your answers did for me, guys.

Answer 5

The simplest way would be using collections.namedtuple.

I find the following 4-liner the most beautiful, which supports nested dictionaries:

def dict_to_namedtuple(typename, data):
    return namedtuple(typename, data.keys())(
        *(dict_to_namedtuple(typename + '_' + k, v) if isinstance(v, dict) else v for k, v in data.items())
    )

The output will look good as well:

>>> nt = dict_to_namedtuple('config', {
...     'path': '/app',
...     'debug': {'level': 'error', 'stream': 'stdout'}
... })

>>> print(nt)
config(path='/app', debug=config_debug(level='error', stream='stdout'))

>>> print(nt.debug.level)
'error'

Answer 6

My dictionary is of this format:

addr_bk = {
    'person': [
        {'name': 'Andrew', 'id': 123, 'email': 'andrew@mailserver.com',
         'phone': [{'type': 2, 'number': '633311122'},
                   {'type': 0, 'number': '97788665'}]
        },
        {'name': 'Tom', 'id': 456,
         'phone': [{'type': 0, 'number': '91122334'}]}, 
        {'name': 'Jack', 'id': 7788, 'email': 'jack@gmail.com'}
    ]
}

As can be seen, I have nested dictionaries and list of dicts. This is because the addr_bk was decoded from protocol buffer data that converted to a python dict using lwpb.codec. There are optional field (e.g. email => where key may be unavailable) and repeated field (e.g. phone => converted to list of dict).

I tried all the above proposed solutions. Some doesn't handle the nested dictionaries well. Others cannot print the object details easily.

Only the solution, dict2obj(dict) by Dawie Strauss, works best.

I have enhanced it a little to handle when the key cannot be found:

# Work the best, with nested dictionaries & lists! :)
# Able to print out all items.
class dict2obj_new(dict):
    def __init__(self, dict_):
        super(dict2obj_new, self).__init__(dict_)
        for key in self:
            item = self[key]
            if isinstance(item, list):
                for idx, it in enumerate(item):
                    if isinstance(it, dict):
                        item[idx] = dict2obj_new(it)
            elif isinstance(item, dict):
                self[key] = dict2obj_new(item)

    def __getattr__(self, key):
        # Enhanced to handle key not found.
        if self.has_key(key):
            return self[key]
        else:
            return None

Then, I tested it with:

# Testing...
ab = dict2obj_new(addr_bk)

for person in ab.person:
  print "Person ID:", person.id
  print "  Name:", person.name
  # Check if optional field is available before printing.
  if person.email:
    print "  E-mail address:", person.email

  # Check if optional field is available before printing.
  if person.phone:
    for phone_number in person.phone:
      if phone_number.type == codec.enums.PhoneType.MOBILE:
        print "  Mobile phone #:",
      elif phone_number.type == codec.enums.PhoneType.HOME:
        print "  Home phone #:",
      else:
        print "  Work phone #:",
      print phone_number.number