from types import SimpleNamespace

sn = SimpleNamespace(a=1, b=2, c=3)

vars(sn)
# returns {'a': 1, 'b': 2, 'c': 3}

sn.__dict__
# also returns {'a': 1, 'b': 2, 'c': 3}

Pass in the dictionary using the **kwargs call syntax to unpack your dictionary into separate arguments:

SimpleNamespace(**d)

This applies each key-value pair in d as a separate keyword argument.

Conversely, the closely related **kwargs parameter definition in the __init__ method of the class definition shown in the Python documentation captures all keyword arguments passed to the class into a single dictionary again.

Demo:

>>> from types import SimpleNamespace
>>> d = {'a': 1, 'b':2}
>>> sn = SimpleNamespace(**d)
>>> sn
namespace(a=1, b=2)
>>> sn.a
1

2022 answer: now there is a tiny, relatively fast library I have published, called dotwiz, which alternatively can be used to provide easy dot access for a python dict object.

It should, coincidentally, be a little faster than the other options -- I've added a quick and dirty benchmark code I put together using the timeit module below, timing against both a attrdict and SimpleNamespace approach -- the latter of which actually performs pretty solid in times.

Note that I had to modify the parse function slightly, so that it handles nested dicts within a list object, for example.

from timeit import timeit
from types import SimpleNamespace

from attrdict import AttrDict
from dotwiz import DotWiz


example_input = {'key0a': "test", 'key0b': {'key1a': [{'key2a': 'end', 'key2b': "test"}], 'key1b': "test"},
                 "something": "else"}


def parse(d):
    x = SimpleNamespace()
    _ = [setattr(x, k,
                 parse(v) if isinstance(v, dict)
                 else [parse(e) for e in v] if isinstance(v, list)
                 else v) for k, v in d.items()]
    return x


print('-- Create')
print('attrdict:         ', round(timeit('AttrDict(example_input)', globals=globals()), 2))
print('dotwiz:           ', round(timeit('DotWiz(example_input)', globals=globals()), 2))
print('SimpleNamespace:  ', round(timeit('parse(example_input)', globals=globals()), 2))
print()

dw = DotWiz(example_input)
ns = parse(example_input)
ad = AttrDict(example_input)

print('-- Get')
print('attrdict:         ', round(timeit('ad.key0b.key1a[0].key2a', globals=globals()), 2))
print('dotwiz:           ', round(timeit('dw.key0b.key1a[0].key2a', globals=globals()), 2))
print('SimpleNamespace:  ', round(timeit('ns.key0b.key1a[0].key2a', globals=globals()), 2))
print()

print(ad)
print(dw)
print(ns)

assert ad.key0b.key1a[0].key2a \
       == dw.key0b.key1a[0].key2a \
       == ns.key0b.key1a[0].key2a \
       == 'end'

Here are the results, on my M1 Mac Pro laptop:

attrdict:          0.69
dotwiz:            1.3
SimpleNamespace:   1.38

-- Get
attrdict:          6.06
dotwiz:            0.06
SimpleNamespace:   0.06

The dotwiz library can be installed with pip:

$ pip install dotwiz

SimpleNamespace is basically just a nice facade on top of a dictionary. It allows you to use properties instead of index keys. This is nice as it is super flexible and easy to manipulate.

The downside of that flexibility is that it doesn't provide any structure. There is nothing to stop someone from calling SimpleNamespace(x=ax, y=ay) (and del a.z at some point later). If this instance gets passed to your function, the exception occurs when you try to access the field.

In contrast, namedtuple lets you create a structured type. The type will have a name and it will know what fields it is supposed to have. You won't be able to make an instance without each of those field and they can't be removed later. Additionally, the instance is immutable, so you will know that the value in a.x will always be the same.

It's up to you to decide if you need the flexibility that SimpleNamespace gives you, or if you prefer to have the structure and guarantees provided by namedtuple.