.. note ::
* Source code at https://github.com/bunbun/nested-dict
* Documentation at http://nested-dict.readthedocs.org
##############################################################################
``nested_dict``
##############################################################################
``nested_dict`` extends ``defaultdict`` to support python ``dict`` with multiple levels of nested-ness:
*****************************************************************
Drop in replacement for ``dict``
*****************************************************************
.. <<Python
.. code-block:: Pycon
>>> from nested_dict import nested_dict
>>> nd= nested_dict()
>>> nd["one"] = "1"
>>> nd[1]["two"] = "1 / 2"
>>> nd["uno"][2]["three"] = "1 / 2 / 3"
>>>
... for keys_as_tuple, value in nd.items_flat():
... print ("%-20s == %r" % (keys_as_tuple, value))
...
('one',) == '1'
(1, 'two') == '1 / 2'
('uno', 2, 'three') == '1 / 2 / 3'
..
Python
Each nested level is created magically when accessed, a process known as "auto-vivification" in perl.
******************************************************************************
Specifying the contained type
******************************************************************************
If you want the nested dictionary to hold
* a collection (like the `set <https://docs.python.org/2/library/sets.html>`__ in the first example) or
* a scalar with useful default values such as ``int`` or ``str``.
==============================
*dict* of ``list``\ s
==============================
.. <<Python
.. code-block:: Python
# nested dict of lists
nd = nested_dict(2, list)
nd["mouse"]["2"].append(12)
nd["human"]["1"].append(12)
..
Python
==============================
*dict* of ``set``\ s
==============================
.. <<Python
.. code-block:: Python
# nested dict of sets
nd = nested_dict(2, set)
nd["mouse"]["2"].add("a")
nd["human"]["1"].add("b")
..
Python
==============================
*dict* of ``int``\ s
==============================
.. <<Python
.. code-block:: Python
# nested dict of ints
nd = nested_dict(2, int)
nd["mouse"]["2"] += 4
nd["human"]["1"] += 5
nd["human"]["1"] += 6
nd.to_dict()
#{'human': {'1': 11}, 'mouse': {'2': 4}}
..
Python
==============================
*dict* of ``str``\ s
==============================
.. <<Python
.. code-block:: Python
# nested dict of strings
nd = nested_dict(2, str)
nd["mouse"]["2"] += "a" * 4
nd["human"]["1"] += "b" * 5
nd["human"]["1"] += "c" * 6
nd.to_dict()
#{'human': {'1': 'bbbbbcccccc'}, 'mouse': {'2': 'aaaa'}}
..
Python
##############################################################################
Iterating through ``nested_dict``
##############################################################################
Iterating through deep or unevenly nested dictionaries is a bit of a pain without recursion.
``nested dict`` allows you to **flatten** the nested levels into `tuple <https://docs.python.org/2/library/functions.html#tuple>`__\ s before iteration.
You do not need to know beforehand how many levels of nesting you have:
.. <<Python
.. code-block:: Python
from nested_dict import nested_dict
nd= nested_dict()
nd["one"] = "1"
nd[1]["two"] = "1 / 2"
nd["uno"][2]["three"] = "1 / 2 / 3"
for keys_as_tuple, value in nd.items_flat():
print ("%-20s == %r" % (keys_as_tuple, value))
# (1, 'two') == '1 / 2'
# ('one',) == '1'
# ('uno', 2, 'three') == '1 / 2 / 3'
..
Python
nested_dict provides
* ``items_flat()``
* ``keys_flat()``
* ``values_flat()``
(``iteritems_flat()``, ``iterkeys_flat()``, and ``itervalues_flat()`` are python 2.7-style synonyms. )
##############################################################################
Converting to / from dictionaries
##############################################################################
The magic of ``nested_dict`` sometimes gets in the way (of `pickle <https://docs.python.org/2/library/pickle.html>`__\ ing for example).
We can convert to and from a vanilla python ``dict`` using
* ``nested_dict.to_dict()``
* ``nested_dict constructor``
.. <<Python
.. code-block:: Pycon
>>> from nested_dict import nested_dict
>>> nd= nested_dict()
>>> nd["one"] = 1
>>> nd[1]["two"] = "1 / 2"
#
# convert nested_dict -> dict and pickle
#
>>> nd.to_dict()
{1: {'two': '1 / 2'}, 'one': 1}
>>> import pickle
>>> binary_representation = pickle.dumps(nd.to_dict())
#
# convert dict -> nested_dict
#
>>> normal_dict = pickle.loads(binary_representation)
>>> new_nd = nested_dict(normal_dict)
>>> nd == new_nd
True
..
Python
##############################################################################
``defaultdict``
##############################################################################
``nested_dict`` extends `collections.defaultdict <https://docs.python.org/2/library/collections.html#collections.defaultdict>`__
You can get arbitrarily-nested "auto-vivifying" dictionaries using `defaultdict <https://docs.python.org/2/library/collections.html#collections.defaultdict>`__.
.. <<Python
.. code-block:: Python
from collections import defaultdict
nested_dict = lambda: defaultdict(nested_dict)
nd = nested_dict()
nd[1][2]["three"][4] = 5
nd["one"]["two"]["three"][4] = 5
..
Python
However, only ``nested_dict`` supports a ``dict`` of ``dict`` of ``sets`` etc.
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"description": ".. note ::\n\n * Source code at https://github.com/bunbun/nested-dict\n * Documentation at http://nested-dict.readthedocs.org\n\n##############################################################################\n``nested_dict``\n##############################################################################\n``nested_dict`` extends ``defaultdict`` to support python ``dict`` with multiple levels of nested-ness:\n\n*****************************************************************\nDrop in replacement for ``dict``\n*****************************************************************\n\n\n .. <<Python\n\n .. code-block:: Pycon\n\n >>> from nested_dict import nested_dict\n >>> nd= nested_dict()\n >>> nd[\"one\"] = \"1\"\n >>> nd[1][\"two\"] = \"1 / 2\"\n >>> nd[\"uno\"][2][\"three\"] = \"1 / 2 / 3\"\n >>>\n ... for keys_as_tuple, value in nd.items_flat():\n ... print (\"%-20s == %r\" % (keys_as_tuple, value))\n ...\n ('one',) == '1'\n (1, 'two') == '1 / 2'\n ('uno', 2, 'three') == '1 / 2 / 3'\n\n ..\n Python\n\n Each nested level is created magically when accessed, a process known as \"auto-vivification\" in perl.\n\n\n******************************************************************************\nSpecifying the contained type\n******************************************************************************\n\n If you want the nested dictionary to hold\n * a collection (like the `set <https://docs.python.org/2/library/sets.html>`__ in the first example) or\n * a scalar with useful default values such as ``int`` or ``str``.\n\n==============================\n*dict* of ``list``\\ s\n==============================\n .. <<Python\n\n .. code-block:: Python\n\n # nested dict of lists\n nd = nested_dict(2, list)\n nd[\"mouse\"][\"2\"].append(12)\n nd[\"human\"][\"1\"].append(12)\n\n\n ..\n Python\n\n==============================\n*dict* of ``set``\\ s\n==============================\n .. <<Python\n\n .. code-block:: Python\n\n # nested dict of sets\n nd = nested_dict(2, set)\n nd[\"mouse\"][\"2\"].add(\"a\")\n nd[\"human\"][\"1\"].add(\"b\")\n\n\n ..\n Python\n\n==============================\n*dict* of ``int``\\ s\n==============================\n\n .. <<Python\n\n .. code-block:: Python\n\n # nested dict of ints\n nd = nested_dict(2, int)\n nd[\"mouse\"][\"2\"] += 4\n nd[\"human\"][\"1\"] += 5\n nd[\"human\"][\"1\"] += 6\n\n nd.to_dict()\n #{'human': {'1': 11}, 'mouse': {'2': 4}}\n\n\n ..\n Python\n\n==============================\n*dict* of ``str``\\ s\n==============================\n\n .. <<Python\n\n .. code-block:: Python\n\n # nested dict of strings\n nd = nested_dict(2, str)\n nd[\"mouse\"][\"2\"] += \"a\" * 4\n nd[\"human\"][\"1\"] += \"b\" * 5\n nd[\"human\"][\"1\"] += \"c\" * 6\n\n nd.to_dict()\n #{'human': {'1': 'bbbbbcccccc'}, 'mouse': {'2': 'aaaa'}}\n\n ..\n Python\n\n##############################################################################\nIterating through ``nested_dict``\n##############################################################################\n\nIterating through deep or unevenly nested dictionaries is a bit of a pain without recursion.\n``nested dict`` allows you to **flatten** the nested levels into `tuple <https://docs.python.org/2/library/functions.html#tuple>`__\\ s before iteration.\n\nYou do not need to know beforehand how many levels of nesting you have:\n\n .. <<Python\n\n .. code-block:: Python\n\n from nested_dict import nested_dict\n nd= nested_dict()\n nd[\"one\"] = \"1\"\n nd[1][\"two\"] = \"1 / 2\"\n nd[\"uno\"][2][\"three\"] = \"1 / 2 / 3\"\n\n for keys_as_tuple, value in nd.items_flat():\n print (\"%-20s == %r\" % (keys_as_tuple, value))\n\n # (1, 'two') == '1 / 2'\n # ('one',) == '1'\n # ('uno', 2, 'three') == '1 / 2 / 3'\n\n ..\n Python\n\n\n\nnested_dict provides\n * ``items_flat()``\n * ``keys_flat()``\n * ``values_flat()``\n\n(``iteritems_flat()``, ``iterkeys_flat()``, and ``itervalues_flat()`` are python 2.7-style synonyms. )\n\n##############################################################################\nConverting to / from dictionaries\n##############################################################################\n\nThe magic of ``nested_dict`` sometimes gets in the way (of `pickle <https://docs.python.org/2/library/pickle.html>`__\\ ing for example).\n\nWe can convert to and from a vanilla python ``dict`` using\n * ``nested_dict.to_dict()``\n * ``nested_dict constructor``\n\n .. <<Python\n\n .. code-block:: Pycon\n\n >>> from nested_dict import nested_dict\n >>> nd= nested_dict()\n >>> nd[\"one\"] = 1\n >>> nd[1][\"two\"] = \"1 / 2\"\n\n #\n # convert nested_dict -> dict and pickle\n #\n >>> nd.to_dict()\n {1: {'two': '1 / 2'}, 'one': 1}\n >>> import pickle\n >>> binary_representation = pickle.dumps(nd.to_dict())\n\n #\n # 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