#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Data Structures
===============
Defines various data structures classes:
- :class:`Structure`: An object similar to C/C++ structured type.
- :class:`Lookup`: A *dict* sub-class acting as a lookup to retrieve keys by
values.
"""
from __future__ import division, unicode_literals
from collections import Mapping, MutableMapping
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013 - 2015 - Colour Developers'
__license__ = 'New BSD License - http://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['Structure',
'Lookup',
'CaseInsensitiveMapping']
[docs]class Structure(dict):
"""
Defines an object similar to C/C++ structured type.
Parameters
----------
\*args : \*
Arguments.
\*\*kwargs : dict
Key / Value pairs.
References
----------
.. [1] Mansencal, T. (n.d.). Structure. Retrieved from
https://github.com/KelSolaar/Foundations/blob/develop/foundations/data_structures.py # noqa
Examples
--------
>>> person = Structure(first_name='Doe', last_name='John', gender='male')
>>> # Doctests skip for Python 2.x compatibility.
>>> person.first_name # doctest: +SKIP
'Doe'
>>> sorted(person.keys())
['first_name', 'gender', 'last_name']
>>> # Doctests skip for Python 2.x compatibility.
>>> person['gender'] # doctest: +SKIP
'male'
"""
def __init__(self, *args, **kwargs):
dict.__init__(self, **kwargs)
self.__dict__.update(**kwargs)
[docs] def __getattr__(self, attribute):
"""
Returns given attribute value.
Parameters
----------
attribute : unicode
Attribute name.
Notes
-----
- Reimplements the :meth:`dict.__getattr__` method.
Returns
-------
object
Attribute value.
Raises
------
AttributeError
If the attribute is not defined.
"""
try:
return dict.__getitem__(self, attribute)
except KeyError:
raise AttributeError('"{0}" object has no attribute "{1}"'.format(
self.__class__.__name__, attribute))
[docs] def __setattr__(self, attribute, value):
"""
Sets both key and sibling attribute with given value.
Parameters
----------
attribute : object
Attribute.
value : object
Value.
Notes
-----
- Reimplements the :meth:`dict.__setattr__` method.
"""
dict.__setitem__(self, attribute, value)
object.__setattr__(self, attribute, value)
__setitem__ = __setattr__
[docs] def __delattr__(self, attribute):
"""
Deletes both key and sibling attribute.
Parameters
----------
attribute : object
Attribute.
Notes
-----
- Reimplements the :meth:`dict.__delattr__` method.
"""
dict.__delitem__(self, attribute)
object.__delattr__(self, attribute)
__delitem__ = __delattr__
[docs] def update(self, *args, **kwargs):
"""
Updates both keys and sibling attributes.
Parameters
----------
\*args : \*
Arguments.
\*\*kwargs : \*\*
Keywords arguments.
Notes
-----
- Reimplements the :meth:`dict.update` method.
"""
dict.update(self, *args, **kwargs)
self.__dict__.update(*args, **kwargs)
[docs]class Lookup(dict):
"""
Extends *dict* type to provide a lookup by value(s).
References
----------
.. [2] Mansencal, T. (n.d.). Lookup. Retrieved from
https://github.com/KelSolaar/Foundations/blob/develop/foundations/data_structures.py # noqa
Examples
--------
>>> person = Lookup(first_name='Doe', last_name='John', gender='male')
>>> person.first_key_from_value('Doe')
'first_name'
>>> persons = Lookup(John='Doe', Jane='Doe', Luke='Skywalker')
>>> sorted(persons.keys_from_value('Doe'))
['Jane', 'John']
"""
[docs] def first_key_from_value(self, value):
"""
Gets the first key with given value.
Parameters
----------
value : object
Value.
Returns
-------
object
Key.
"""
for key, data in self.items():
if data == value:
return key
[docs] def keys_from_value(self, value):
"""
Gets the keys with given value.
Parameters
----------
value : object
Value.
Returns
-------
object
Keys.
"""
return [key for key, data in self.items() if data == value]
[docs]class CaseInsensitiveMapping(MutableMapping):
"""
Implements a case-insensitive mutable mapping / *dict* object.
Allows values retrieving from keys while ignoring the key case.
The keys are expected to be unicode or string-like objects supporting the
:meth:`str.lower` method.
Parameters
----------
data : dict
*dict* of data to store into the mapping at initialisation.
\*\*kwargs : dict
Key / Value pairs to store into the mapping at initialisation.
Warning
-------
The keys are expected to be unicode or string-like objects.
References
----------
.. [3] Reitz, K. (n.d.). CaseInsensitiveDict. Retrieved from
https://github.com/kennethreitz/requests/blob/v1.2.3/requests/structures.py#L37 # noqa
Examples
--------
>>> methods = CaseInsensitiveMapping({'McCamy': 1, 'Hernandez': 2})
>>> methods['mccamy']
1
"""
def __init__(self, data=None, **kwargs):
self.__data = dict()
if data is None:
data = {}
self.update(data, **kwargs)
[docs] def __setitem__(self, item, value):
"""
Sets given item with given value.
The item is stored as lower in the mapping while the original name and
its value are stored together as the value in a *tuple*:
{"item.lower()": ("item", value)}
Parameters
----------
item : object
Attribute.
value : object
Value.
Notes
-----
- Reimplements the :meth:`MutableMapping.__setitem__` method.
"""
self.__data[item.lower()] = (item, value)
[docs] def __getitem__(self, item):
"""
Returns the value of given item.
The item value is retrieved using its lower name in the mapping.
Parameters
----------
item : unicode
Item name.
Returns
-------
object
Item value
Notes
-----
- Reimplements the :meth:`MutableMapping.__getitem__` method.
"""
return self.__data[item.lower()][1]
[docs] def __delitem__(self, item):
"""
Deletes the item with given name.
The item is deleted from the mapping using its lower name.
Parameters
----------
item : unicode
Item name.
Notes
-----
- Reimplements the :meth:`MutableMapping.__delitem__` method.
"""
del self.__data[item.lower()]
[docs] def __contains__(self, item):
"""
Returns if the mapping contains given item.
Parameters
----------
item : unicode
Item name.
Returns
-------
bool
Is item in mapping.
Notes
-----
- Reimplements the :meth:`MutableMapping.__contains__` method.
"""
return item.lower() in self.__data
[docs] def __iter__(self):
"""
Iterates over the items names in the mapping.
The item names returned are the original input ones.
Returns
-------
generator
Item names.
Notes
-----
- Reimplements the :meth:`MutableMapping.__iter__` method.
"""
return (item for item, value in self.__data.values())
[docs] def __len__(self):
"""
Returns the items count.
Returns
-------
int
Items count.
Notes
-----
- Reimplements the :meth:`MutableMapping.__iter__` method.
"""
return len(self.__data)
[docs] def __eq__(self, item):
"""
Returns the equality with given object.
Parameters
----------
item
Object item.
Returns
-------
bool
Equality.
Notes
-----
- Reimplements the :meth:`MutableMapping.__eq__` method.
"""
if isinstance(item, Mapping):
item = CaseInsensitiveMapping(item)
else:
return NotImplemented
return dict(self.lower_items()) == dict(item.lower_items())
[docs] def __ne__(self, item):
"""
Returns the inequality with given object.
Parameters
----------
item
Object item.
Returns
-------
bool
Inequality.
Notes
-----
- Reimplements the :meth:`MutableMapping.__ne__` method.
"""
return not (self == item)
[docs] def __repr__(self):
"""
Returns the mapping representation with the original item names.
Returns
-------
unicode
Mapping representation.
Notes
-----
- Reimplements the :meth:`MutableMapping.__repr__` method.
"""
return '{0}({1})'.format(self.__class__.__name__, dict(self.items()))
[docs] def copy(self):
"""
Returns a copy of the mapping.
Returns
-------
CaseInsensitiveMapping
Mapping copy.
Notes
-----
- The :class:`CaseInsensitiveMapping` class copy returned is a simple
*copy* not a *deepcopy*.
"""
return CaseInsensitiveMapping(self.__data.values())
[docs] def lower_items(self):
"""
Iterates over the lower items names.
Returns
-------
generator
Lower item names.
"""
return ((item, value[1]) for (item, value) in self.__data.items())
Colour 0.3