orderedattrdict
===============
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An ordered dictionary with attribute-style access.
Usage
-----
``AttrDict`` behaves exactly like ``collections.OrderedDict``, but also allows
keys to be accessed as attributes::
>>> from orderedattrdict import AttrDict
>>> conf = AttrDict()
>>> conf['z'] = 1
>>> assert conf.z == 1
>>> conf.y = 2
>>> assert conf['y'] == 2
>>> conf.x = 3
>>> assert conf.keys() == ['z', 'y', 'x']
**NOTE**: If the key clashes with an ``OrderedDict`` attribute or starts with
``__`` (two underscores), you can't access it as an attribute. For example::
>>> a = AttrDict(keys=1)
>>> a.keys
<bound method AttrDict.keys of AttrDict([('keys', 1)])>
>>> a['keys']
1
Load JSON preserving the order of keys::
>>> import json
>>> data = json.load(open('test.json'), object_pairs_hook=AttrDict)
Load YAML preserving the order of keys::
>>> import yaml
>>> from orderedattrdict.yamlutils import AttrDictYAMLLoader
>>> data = yaml.load(open('test.yaml'), Loader=AttrDictYAMLLoader)
Make PyYAML *always* load all dictionaries as ``AttrDict``::
>>> from orderedattrdict.yamlutils import from_yaml
>>> yaml.add_constructor(u'tag:yaml.org,2002:map', from_yaml)
>>> yaml.add_constructor(u'tag:yaml.org,2002:omap', from_yaml)
``json.dump``, ``yaml.dump`` and ``yaml.safe_dump`` convert ``AttrDict`` into
dictionaries, retaining the order::
>>> json.dumps(data)
>>> yaml.dump(data)
CounterAttrDict
---------------
``CounterAttrDict`` provides a Counter with ordered keys and attribute-style
access::
>>> from orderedattrdict import CounterAttrDict
>>> c = CounterAttrDict()
>>> c.x
0
>>> c.elements
<bound method CounterAttrDict.elements of CounterAttrDict()>
>>> c.x += 1
>>> c.y += 2
>>> c.most_common()
[('y', 2), ('x', 1)]
>>> list(c.elements())
['x', 'y', 'y']
>>> c.subtract(y=1)
>>> c
CounterAttrDict([('x', 1), ('y', 1)])
DefaultAttrDict
---------------
``DefaultAttrDict`` provides a defaultdict with ordered keys and attribute-style
access. This can be used with a list factory to collect items::
>>> from orderedattrdict import DefaultDict
>>> d = DefaultAttrDict(list)
>>> d.x.append(10) # Append item without needing to initialise list
>>> d.x.append(20)
>>> sum(d.x)
30
or with a set to collect unique items::
>>> d = DefaultAttrDict(set)
>>> d.x.add(5)
>>> d.x.add(2)
>>> d.x.add(5) # Duplicate item is ignored
>>> sum(d.x)
7
Tree
----
``Tree`` lets you can set attributes in any level of the hierarchy::
>>> node = Tree()
>>> node
Tree()
>>> node.x.y = 1
>>> node
Tree([('x', Tree([('y', 1)]))])
>>> node.x.z = 2
>>> node
Tree([('x', Tree([('y', 1), ('z', 2)]))])
>>> node.y.a.b = 3
>>> node
Tree([('x', Tree([('y', 1), ('z', 2)])), ('y', Tree([('a', Tree([('b', 3)]))]))])
Installation
------------
This is a pure-Python package built for Python 2.7+ and Python 3.0+. To set up::
pip install orderedattrdict
Updating
--------
Test locally::
rm -rf build dist
flake8 .
python setup.py test
Update version in ``setup.py`` and ``Changelog`` below. Then commit. Then::
git tag -a v1.x.x # Annotate with a one-line summary of features
git push --follow-tags
# Ensure that travis builds pass
python setup.py sdist bdist_wheel --universal
twine upload dist/*
Changelog
---------
- ``1.0``: Basic implementation
- ``1.1``: Add utilities to load and save as YAML
- ``1.2``: Allow specific keys to be excluded from attribute access
- ``1.3``: Restore ``<<`` merge tags for YAML
- ``1.4.1``: Add ``CounterAttrDict`` and ``DefaultAttrDict``
- ``1.4.2``: Add Python 3.5 support
- ``1.4.3``: Fix bdist installation issues for Python 2.7
- ``1.5``: Add ``Tree`` data structure
- ``1.6``: ``str()`` prints human-friendly dict