Metadata-Version: 2.1
Name: flatten-dict
Version: 0.2.0.dev0
Summary: A flexible utility for flattening and unflattening dict-like objects in Python.
Home-page: https://github.com/ianlini/flatten-dict
License: MIT
Author: Ian Lin
Author-email: you@example.com
Requires-Python: >=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*
Classifier: License :: OSI Approved :: MIT License
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Topic :: Utilities
Requires-Dist: pathlib2 (>=2.3,<3.0)
Requires-Dist: six (>=1.12,<2.0)
Project-URL: Repository, https://github.com/ianlini/flatten-dict
Description-Content-Type: text/x-rst

flatten-dict
============
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   :target: https://travis-ci.org/ianlini/flatten-dict
.. image:: https://img.shields.io/pypi/v/flatten-dict.svg
   :target: https://pypi.python.org/pypi/flatten-dict
.. image:: https://img.shields.io/pypi/l/flatten-dict.svg
   :target: https://pypi.python.org/pypi/flatten-dict

A flexible utility for flattening and unflattening dict-like objects in Python.


Introduction
------------
This Python package provide a function ``flatten()`` for flattening dict-like objects.
It also provides some key joining methods (reducer), and you can choose the reducer you want or even implement your own reducer. You can also choose to invert the resulting flat dict.

Documentation
-------------

Flatten
```````

.. code-block:: python

   def flatten(d, reducer='tuple', inverse=False, enumerate_types=()):
       """Flatten `Mapping` object.

       Parameters
       ----------
       d : dict-like object
           The dict that will be flattened.
       reducer : {'tuple', 'path', 'underscore', Callable}
           The key joining method. If a `Callable` is given, the `Callable` will be
           used to reduce.
           'tuple': The resulting key will be tuple of the original keys.
           'path': Use `os.path.join` to join keys.
           'underscore': Use underscores to join keys.
       inverse : bool
           Whether you want invert the resulting key and value.
       enumerate_types : Sequence[type]
           Flatten these types using `enumerate`.
           For example, if we set `enumerate_types` to ``(list,)``,
           `list` indices become keys: ``{'a': ['b', 'c']}`` -> ``{('a', 0): 'b', ('a', 1): 'c'}``.

       Returns
       -------
       flat_dict : dict
       """

Examples
::::::::

.. code-block:: python

   In [1]: from flatten_dict import flatten

   In [2]: normal_dict = {
      ...:     'a': '0',
      ...:     'b': {
      ...:         'a': '1.0',
      ...:         'b': '1.1',
      ...:     },
      ...:     'c': {
      ...:         'a': '2.0',
      ...:         'b': {
      ...:             'a': '2.1.0',
      ...:             'b': '2.1.1',
      ...:         },
      ...:     },
      ...: }

   In [3]: flatten(normal_dict)
   Out[3]:
   {('a',): '0',
    ('b', 'a'): '1.0',
    ('b', 'b'): '1.1',
    ('c', 'a'): '2.0',
    ('c', 'b', 'a'): '2.1.0',
    ('c', 'b', 'b'): '2.1.1'}

   In [4]: flatten(normal_dict, reducer='path')
   Out[4]:
   {'a': '0',
    'b/a': '1.0',
    'b/b': '1.1',
    'c/a': '2.0',
    'c/b/a': '2.1.0',
    'c/b/b': '2.1.1'}

   In [5]: flatten(normal_dict, reducer='path', inverse=True)
   Out[5]:
   {'0': 'a',
    '1.0': 'b/a',
    '1.1': 'b/b',
    '2.0': 'c/a',
    '2.1.0': 'c/b/a',
    '2.1.1': 'c/b/b'}

   In [6]: def underscore_reducer(k1, k2):
      ...:     if k1 is None:
      ...:         return k2
      ...:     else:
      ...:         return k1 + "_" + k2
      ...:

   In [7]: flatten(normal_dict, reducer=underscore_reducer)
   Out[7]:
   {'a': '0',
    'b_a': '1.0',
    'b_b': '1.1',
    'c_a': '2.0',
    'c_b_a': '2.1.0',
    'c_b_b': '2.1.1'}

If we have some iterable (e.g., `list`) in the `dict`, we will normally get this:

.. code-block:: python

   In [8]: flatten({'a': [1, 2, 3], 'b': 'c'})
   Out[8]:
   {('a',): [1, 2, 3],
    ('b',): 'c'}

If we want to use its indices as keys, then we can use the parameter `enumerate_types`:

.. code-block:: python

   In [9]: flatten({'a': [1, 2, 3], 'b': 'c'}, enumerate_types=(list,))
   Out[9]:
   {('a', 0): 1,
    ('a', 1): 2,
    ('a', 2): 3,
    ('b',): 'c'}

We can even flatten a `list` directly:

.. code-block:: python

   In [10]: flatten([1, 2, 3], enumerate_types=(list,))
   Out[10]:
   {(0,): 1,
    (1,): 2,
    (2,): 3}

Unflatten
`````````

.. code-block:: python

   def unflatten(d, splitter='tuple', inverse=False):
       """Unflatten dict-like object.

       Parameters
       ----------
       d : dict-like object
           The dict that will be unflattened.
       splitter : {'tuple', 'path', 'underscore', Callable}
           The key splitting method. If a Callable is given, the Callable will be
           used to split.
           'tuple': Use each element in the tuple key as the key of the unflattened dict.
           'path': Use `pathlib.Path.parts` to split keys.
           'underscore': Use underscores to split keys.
       inverse : bool
           Whether you want to invert the key and value before flattening.

       Returns
       -------
       unflattened_dict : dict
       """

Examples
::::::::

.. code-block:: python

   In [1]: from flatten_dict import unflatten

   In [2]: flat_dict = {
      ...:     ('a',): '0',
      ...:     ('b', 'a'): '1.0',
      ...:     ('b', 'b'): '1.1',
      ...:     ('c', 'a'): '2.0',
      ...:     ('c', 'b', 'a'): '2.1.0',
      ...:     ('c', 'b', 'b'): '2.1.1',
      ...: }

   In [3]: unflatten(flat_dict)
   Out[3]:
   {'a': '0',
    'b': {'a': '1.0', 'b': '1.1'},
    'c': {'a': '2.0', 'b': {'a': '2.1.0', 'b': '2.1.1'}}}

   In [4]: flat_dict = {
      ...:     'a': '0',
      ...:     'b/a': '1.0',
      ...:     'b/b': '1.1',
      ...:     'c/a': '2.0',
      ...:     'c/b/a': '2.1.0',
      ...:     'c/b/b': '2.1.1',
      ...: }

   In [5]: unflatten(flat_dict, splitter='path')
   Out[5]:
   {'a': '0',
    'b': {'a': '1.0', 'b': '1.1'},
    'c': {'a': '2.0', 'b': {'a': '2.1.0', 'b': '2.1.1'}}}

   In [6]: flat_dict = {
      ...:     '0': 'a',
      ...:     '1.0': 'b/a',
      ...:     '1.1': 'b/b',
      ...:     '2.0': 'c/a',
      ...:     '2.1.0': 'c/b/a',
      ...:     '2.1.1': 'c/b/b',
      ...: }

   In [7]: unflatten(flat_dict, splitter='path', inverse=True)
   Out[7]:
   {'a': '0',
    'b': {'a': '1.0', 'b': '1.1'},
    'c': {'a': '2.0', 'b': {'a': '2.1.0', 'b': '2.1.1'}}}

   In [8]: def underscore_splitter(flat_key):
      ...:     return flat_key.split("_")
      ...:

   In [9]: flat_dict = {
      ...:     'a': '0',
      ...:     'b_a': '1.0',
      ...:     'b_b': '1.1',
      ...:     'c_a': '2.0',
      ...:     'c_b_a': '2.1.0',
      ...:     'c_b_b': '2.1.1',
      ...: }

   In [10]: unflatten(flat_dict, splitter=underscore_splitter)
   Out[10]:
   {'a': '0',
    'b': {'a': '1.0', 'b': '1.1'},
    'c': {'a': '2.0', 'b': {'a': '2.1.0', 'b': '2.1.1'}}}

