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attrdict 0.2.1

A dict with attribute-style access

Latest Version: 2.0.0

AttrDict is a 2.6, 2.7, 3-compatible dictionary that allows its elements to be accessed both as keys and as attributes:

> from attrdict import AttrDict
> a = AttrDict({'foo': 'bar'})
> a['foo']

With this, you can easily create convenient, heirarchical settings objects.

with open('settings.yaml', 'r') as fileobj:
    settings = AttrDict(yaml.safe_load(fileobj))

cursor = connect(**settings.db.credentials).cursor()

cursor.execute("SELECT column FROM table");


AttrDict is in PyPI, so it can be installed directly using:

$ pip install attrdict

Or from Github:

$ git clone
$ cd AttrDict
$ python install


Documentation is available at



An empty AttrDict can be created with:

a = AttrDict()

Or, you can pass an existing dict (or other type of Mapping object):

a = AttrDict({'foo': 'bar'})

NOTE: Unlike dict, AttrDict will not clone on creation. AttrDict’s internal dictionary will be the same instance as the dict passed in.


AttrDict can be used exactly like a normal dict:

> a = AttrDict()
> a['foo'] = 'bar'
> a['foo']
> '{foo}'.format(**a)
> del a['foo']
> a.get('foo', 'default')

AttrDict can also have it’s keys manipulated as attributes to the object:

> a = AttrDict()
> = 'bar'
> del

Both methods operate on the same underlying object, so operations are interchangeable. The only difference between the two methods is that where dict-style access would return a dict, attribute-style access will return an AttrDict. This allows recursive attribute-style access:

> a = AttrDict({'foo': {'bar': 'baz'}})
> a['foo'].bar
AttributeError: 'dict' object has no attribute 'bar'

There are some valid keys that cannot be accessed as attributes. To be accessed as an attribute, a key must:

  • be a string
  • start with an alphabetic character
  • be comprised solely of alphanumeric characters and underscores
  • not map to an existing attribute name (e.g., get, items)

To access these attributes while retaining an AttrDict wrapper (or to dynamically access any key as an attribute):

> a = AttrDict({'_foo': {'bar': 'baz'}})
> a('_foo').bar


AttrDicts can be merged with eachother or other dict objects using the + operator. For conflicting keys, the right dict’s value will be preferred, but in the case of two dictionary values, they will be recursively merged:

> a = {'foo': 'bar', 'alpha': {'beta': 'a', 'a': 'a'}}
> b = {'lorem': 'ipsum', 'alpha': {'bravo': 'b', 'a': 'b'}}
> AttrDict(a) + b
{'foo': 'bar', 'lorem': 'ipsum', 'alpha': {'beta': 'a', 'bravo': 'b', 'a': 'b'}}

NOTE: AttrDict’s add is not associative, a + b != b + a:

> a = {'foo': 'bar', 'alpha': {'beta': 'b', 'a': 0}}
> b = {'lorem': 'ipsum', 'alpha': {'bravo': 'b', 'a': 1}}
> b + AttrDict(a)
{'foo': 'bar', 'lorem': 'ipsum', 'alpha': {'beta': 'a', 'bravo': 'b', 'a': }}


By default, items in non-string Sequences (e.g. lists, tuples) will be converted to AttrDicts:

> adict = AttrDict({'list': [{'value': 1}, 'value': 2]})
> for element in adict.list:
>     element.value

This will not occur if you access the AttrDict as a dictionary:

> adict = AttrDict({'list': [{'value': 1}, 'value': 2]})
> for element in adict['list']:
>     isinstance(element, AttrDict)

To disable this behavior globally, pass the attribute recursive=False to the constructor:

> adict = AttrDict({'list': [{'value': 1}, 'value': 2]}, recursive=False)
> for element in adict['list']:
>     isinstance(element, AttrDict)

When merging an AttrDict with another mapping, this behavior will be disabled if at least one of the merged items is an AttrDict that has set recursive to False.


A common usage for AttrDict is to use it in combination with settings files to create hierarchical settings:

from attrdict import AttrDict
import yaml

def load(*filenames):
    Returns a settings dict built from a list of settings files.

    filenames: The names of any number of settings files.
    settings = AttrDict()

    for filename in filenames:
        with open(filename, 'r') as fileobj:
            settings += yaml.safe_load(fileobj)

    return settings

By accepting multiple files, settings can allow for default settings and provide overrides, e.g.:

# config.yaml =
# emergency:
#   email:
#   message: Something went wrong
# user.yaml =
# emergency:
#   email:
settings = load('config.yaml', 'user.yaml')

assert == ''
assert settings.message == 'Something went wrong'


AttrDict is released under a MIT license.

File Type Py Version Uploaded on Size
attrdict-0.2.1.tar.gz (md5) Source 2014-03-19 8KB
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