Source code for colour.utilities.data_structures

#!/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 - 2014 - 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] https://github.com/KelSolaar/Foundations/blob/develop/foundations/data_structures.py # noqa Examples -------- >>> person = Structure(firstName='Doe', lastName='John', gender='male') >>> # Doctests skip for Python 2.x compatibility. >>> person.firstName # doctest: +SKIP 'Doe' >>> sorted(person.keys()) ['firstName', 'gender', 'lastName'] >>> # 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] https://github.com/KelSolaar/Foundations/blob/develop/foundations/data_structures.py # noqa Examples -------- >>> person = Lookup(firstName='Doe', lastName='John', gender='male') >>> person.first_key_from_value('Doe') 'firstName' >>> 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] 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())