colour.utilities.data_structures Module

Data Structures

Defines various data structures classes:

• ArbitraryPrecisionMapping: A mutable mapping / dict like object where numeric keys are stored with an arbitrary precision.
• Structure: An object similar to C/C++ structured type.
• Lookup: A dict sub-class acting as a lookup to retrieve keys by values.
• CaseInsensitiveMapping: A case insensitive mapping allowing values retrieving from keys while ignoring the key case.

class colour.utilities.data_structures.ArbitraryPrecisionMapping(data=None, key_decimals=0, **kwargs)

Bases: _abcoll.MutableMapping

Implements a mutable mapping / dict like object where numeric keys are stored with an arbitrary precision.

Parameters:

• data (dict, optional) – dict of data to store into the mapping at initialisation.
• key_decimals (int, optional) – Decimals count the keys will be rounded at
• **kwargs (dict, optional) – Key / Value pairs to store into the mapping at initialisation.

key_decimals

__setitem__()

__getitem__()

__delitem__()

__contains__()

__iter__()

__len__()

Examples

>>> data1 = {0.1999999998: 'Nemo', 0.2000000000: 'John'}
>>> apm1 = ArbitraryPrecisionMapping(data1, key_decimals=10)
>>> # Doctests skip for Python 2.x compatibility.
>>> tuple(apm1.keys())  
(0.1999999998, 0.2)
>>> apm2 = ArbitraryPrecisionMapping(data1, key_decimals=7)
>>> # Doctests skip for Python 2.x compatibility.
>>> tuple(apm2.keys())  
(0.2,)

__contains__(item)

Returns if the mapping contains given item (rounded if numeric).

Parameters:item (unicode) – Item (rounded if numeric) name. Returns:Is item in mapping. Return type:bool

Notes

• Reimplements the MutableMapping.__contains__() method.

__delitem__(item)

Deletes the item (rounded if numeric) with given value.

Parameters:item (unicode) – Item (rounded if numeric) name.

Notes

• Reimplements the MutableMapping.__delitem__() method.

__getitem__(item)

Returns the value of given item (rounded if numeric).

Parameters:item (unicode) – Item (rounded if numeric) name. Returns:Item value. Return type:object

Notes

• Reimplements the MutableMapping.__getitem__() method.

__iter__()

Iterates over the items (rounded if numeric) names in the mapping.

Returns:Item names. Return type:generator

Notes

• Reimplements the MutableMapping.__iter__() method.

__len__()

Returns the items count.

Returns:Items count. Return type:int

Notes

• Reimplements the MutableMapping.__iter__() method.

__setitem__(item, value)

Sets given item (rounded if numeric) with given value.

Parameters:

• item (object) – Attribute.
• value (object) – Value.

Returns:

Item value (rounded if numeric).

Return type:

object

Notes

• Reimplements the MutableMapping.__setitem__() method.

key_decimals

Property for self._key_decimals private attribute.

Returns:self._key_decimals. Return type:unicode

class colour.utilities.data_structures.Structure(*args, **kwargs)

Bases: dict

Defines an object similar to C/C++ structured type.

Parameters:

• *args (list, optional) – Arguments.
• **kwargs (dict, optional) – Key / Value pairs.

__getattr__()

__setattr__()

__delattr__()

update()

References

[1]	Mansencal, T. (n.d.). Structure. Retrieved from https://github.com/KelSolaar/Foundations/blob/develop/foundations/data_structures.py

Examples

>>> person = Structure(first_name='Doe', last_name='John', gender='male')
>>> # Doctests skip for Python 2.x compatibility.
>>> person.first_name  
'Doe'
>>> sorted(person.keys())
['first_name', 'gender', 'last_name']
>>> # Doctests skip for Python 2.x compatibility.
>>> person['gender']  
'male'

__delattr__(attribute)

Deletes both key and sibling attribute.

Parameters:attribute (object) – Attribute.

Notes

• Reimplements the dict.__delattr__() method.

__delitem__(attribute)

Deletes both key and sibling attribute.

Parameters:attribute (object) – Attribute.

Notes

• Reimplements the dict.__delattr__() method.

__getattr__(attribute)

Returns given attribute value.

Parameters:attribute (unicode) – Attribute name.

Notes

• Reimplements the dict.__getattr__() method.

Returns:Attribute value. Return type:object Raises:AttributeError – If the attribute is not defined.

__setattr__(attribute, value)

Sets both key and sibling attribute with given value.

Parameters:

• attribute (object) – Attribute.
• value (object) – Value.

Notes

• Reimplements the dict.__setattr__() method.

__setitem__(attribute, value)

Sets both key and sibling attribute with given value.

Parameters:

• attribute (object) – Attribute.
• value (object) – Value.

Notes

• Reimplements the dict.__setattr__() method.

update(*args, **kwargs)

Updates both keys and sibling attributes.

Parameters:

• *args (list, optional) – Arguments.
• **kwargs (dict, optional) – Keywords arguments.

Notes

• Reimplements the dict.update() method.

class colour.utilities.data_structures.Lookup

Bases: dict

Extends dict type to provide a lookup by value(s).

first_key_from_value()

keys_from_value()

References

[2]	Mansencal, T. (n.d.). Lookup. Retrieved from https://github.com/KelSolaar/Foundations/blob/develop/foundations/data_structures.py

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']

first_key_from_value(value)

Gets the first key with given value.

Parameters:value (object) – Value. Returns:Key. Return type:object

keys_from_value(value)

Gets the keys with given value.

Parameters:value (object) – Value. Returns:Keys. Return type:object

class colour.utilities.data_structures.CaseInsensitiveMapping(data=None, **kwargs)

Bases: _abcoll.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 str.lower() method.

Parameters:

• data (dict) – dict of data to store into the mapping at initialisation.
• **kwargs (dict, optional) – Key / Value pairs to store into the mapping at initialisation.

__setitem__()

__getitem__()

__delitem__()

__contains__()

__iter__()

__len__()

__eq__()

__ne__()

__repr__()

copy()

lower_items()

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

Examples

>>> methods = CaseInsensitiveMapping({'McCamy': 1, 'Hernandez': 2})
>>> methods['mccamy']
1

__contains__(item)

Returns if the mapping contains given item.

Parameters:item (unicode) – Item name. Returns:Is item in mapping. Return type:bool

Notes

• Reimplements the MutableMapping.__contains__() method.

__delitem__(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 MutableMapping.__delitem__() method.

__eq__(item)

Returns the equality with given object.

Parameters:item – Object item. Returns:Equality. Return type:bool

Notes

• Reimplements the MutableMapping.__eq__() method.

__getitem__(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:Item value. Return type:object

Notes

• Reimplements the MutableMapping.__getitem__() method.

__iter__()

Iterates over the items names in the mapping.

The item names returned are the original input ones.

Returns:Item names. Return type:generator

Notes

• Reimplements the MutableMapping.__iter__() method.

__len__()

Returns the items count.

Returns:Items count. Return type:int

Notes

• Reimplements the MutableMapping.__iter__() method.

__ne__(item)

Returns the inequality with given object.

Parameters:item – Object item. Returns:Inequality. Return type:bool

Notes

• Reimplements the MutableMapping.__ne__() method.

__repr__()

Returns the mapping representation with the original item names.

Returns:Mapping representation. Return type:unicode

Notes

• Reimplements the MutableMapping.__repr__() method.

__setitem__(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 MutableMapping.__setitem__() method.

copy()

Returns a copy of the mapping.

Returns:Mapping copy. Return type:CaseInsensitiveMapping

Notes

• The CaseInsensitiveMapping class copy returned is a simple copy not a deepcopy.

lower_items()

Iterates over the lower items names.

Returns:Lower item names. Return type:generator