Characteristics

The galactic.characteristics module defines characteristics.

Characteristic for the superclass of all characteristics;
Imprecise for multi-valued characteristics;
MultipleValue for transforming characteristic into multi-valued characteristics;
Named for named characteristics;
Key for characteristics whose calls to an individual will be retrieved by a key access;
Property for characteristics whose calls to an individual will be retrieved by a property access;
Item for characteristics whose calls to an individual will be retrieved by a nth access;
Slice for characteristics whose calls to an individual will be retrieved by a slice access.

class Characteristic(*components: Characteristic, cache: bool = True, **kwargs: Any)

The Characteristic class is the super class of all characteristics.

It is designed for subclassing.

A characteristic can be called on an individual. It returns a data of this individual.

__call__(individual: Any) → Optional[Any]

Make this characteristic callable.

This method should be overridden in sub-classes.

Parameters:: individual (object) – Any python object.
Returns:: The individual characteristic.
Return type:: Any, optional

Hint

If the returned value is None, the characteristic is undetermined.

__init__(*components: Characteristic, cache: bool = True, **kwargs: Any) → None

Initialise a Characteristic instance.

Parameters:

*components (Characteristic) – Inner characteristics (if any).

Keyword Arguments:

cache (bool) – Is this characteristic is cached?
**kwargs (Any) – Additional keyword arguments.

property cache: bool

Get the cache property.

Returns:: The cache property.
Return type:: bool

clear() → None: Clear the cache.

property components: Sequence[Characteristic]

Get the inner characteristics.

Returns:: The inner characteristics.
Return type:: Sequence[Characteristic]

property explanation: str

Get the explanation.

Returns:: The explanation.
Return type:: str

property label: str

Get the label.

Returns:: The label.
Return type:: str

class Imprecise(*components: Characteristic, cache: bool = True, **kwargs: Any)

The Imprecise class is used to represent multi-valued characteristics.

A call to these characteristics returns an optional collection of values.

__call__(individual: Any) → Optional[Any]

Return an optional collection of values from the individual.

Returns:: An optional collection. The None value represents a completely unknown value.
Return type:: Collection[Any], optional

__init__(*components: Characteristic, cache: bool = True, **kwargs: Any) → None

Initialise a Characteristic instance.

Parameters:

*components (Characteristic) – Inner characteristics (if any).

Keyword Arguments:

cache (bool) – Is this characteristic is cached?
**kwargs (Any) – Additional keyword arguments.

property cache: bool

Get the cache property.

Returns:: The cache property.
Return type:: bool

clear() → None: Clear the cache.

property components: Sequence[Characteristic]

Get the inner characteristics.

Returns:: The inner characteristics.
Return type:: Sequence[Characteristic]

property explanation: str

Get the explanation.

Returns:: The explanation.
Return type:: str

property label: str

Get the label.

Returns:: The label.
Return type:: str

class MultipleValue(characteristic: Optional[Characteristic] = None, multiple: bool = False, **kwargs: Any)

The MultipleValue class.

It is used to transform a characteristic info a multi-valued characteristic.

__call__(individual: Any) → Optional[Any]

Return an optional collection from the individual.

Returns:: An optional collection. The None value represents a completely unknown value.
Return type:: Collection[Any], optional

__init__(characteristic: Optional[Characteristic] = None, multiple: bool = False, **kwargs: Any) → None

Initialise a MultipleValue instance.

Parameters:: characteristic (:class`Characteristic`, optional) – Inner characteristic (if any).
Keyword Arguments:: multiple (bool) – Do characteristic produce multiple values?

property cache: bool

Get the cache property.

Returns:: The cache property.
Return type:: bool

property characteristic: Optional[Characteristic]

Get the underlying characteristic.

Returns:: The underlying characteristic.
Return type:: Characteristic

clear() → None: Clear the cache.

property components: Sequence[Characteristic]

Get the inner characteristics.

Returns:: The inner characteristics.
Return type:: Sequence[Characteristic]

classmethod constructor(value: Any) → Optional[Any]

Transform a value.

Parameters:: value – The value to transform
Returns:: The transformed value
Return type:: Any, optional

property explanation: str

Get the explanation.

Returns:: The explanation.
Return type:: str

property label: str

Get the label.

Returns:: The label.
Return type:: str

property multiple: bool

Get the multiple property.

Returns:: The multiple property.
Return type:: bool

class Named(name: str, characteristic: Optional[Characteristic] = None, **kwargs: Any)

The Named class is used to represent named characteristics.

Is is designed for subclassing.

__call__(individual: Any) → Optional[Any]

Make this characteristic callable.

This method should be overridden in sub-classes.

Parameters:: individual (object) – Any python object.
Returns:: The individual characteristic.
Return type:: Any, optional

Hint

If the returned value is None, the characteristic is undetermined.

__init__(name: str, characteristic: Optional[Characteristic] = None, **kwargs: Any) → None

Initialise a Named instance.

Parameters:

name – A name (usually a string)

Keyword Arguments:

characteristic (Characteristic, optional) – The inner characteristic (if any)
**kwargs – Unused but useful for multi-class inheritance.

property cache: bool

Get the cache property.

Returns:: The cache property.
Return type:: bool

property characteristic: Optional[Characteristic]

Get the inner characteristic.

Returns:: The inner characteristic.
Return type:: Characteristic, optional

clear() → None: Clear the cache.

property components: Sequence[Characteristic]

Get the inner characteristics.

Returns:: The inner characteristics.
Return type:: Sequence[Characteristic]

property explanation: str

Get the explanation.

Returns:: The explanation.
Return type:: str

property label: str

Get the label.

Returns:: The label.
Return type:: str

property name: str

Get the name.

Returns:: The name.
Return type:: str

class Key(name: str, characteristic: Optional[Characteristic] = None, **kwargs: Any)

The Key class is used to represent key characteristics.

Example

>>> from galactic.characteristics import Key
>>> a = Key(name="x")
>>> print(a)
x
>>> a({"x": 5})
5
>>> a({})
>>> a=Key(name="y", characteristic=Key(name="x"))
>>> print(a)
x[y]
>>> a({"x": {"y": 5}})
5

__call__(individual: Any) → Optional[Any]

Make this characteristic callable.

Parameters:: individual (object) – Any python object
Returns:: The individual key using an array access or None if the individual does not have this key.
Return type:: Any, optional

__init__(name: str, characteristic: Optional[Characteristic] = None, **kwargs: Any) → None

Initialise a Named instance.

Parameters:

name – A name (usually a string)

Keyword Arguments:

characteristic (Characteristic, optional) – The inner characteristic (if any)
**kwargs – Unused but useful for multi-class inheritance.

property cache: bool

Get the cache property.

Returns:: The cache property.
Return type:: bool

property characteristic: Optional[Characteristic]

Get the inner characteristic.

Returns:: The inner characteristic.
Return type:: Characteristic, optional

clear() → None: Clear the cache.

property components: Sequence[Characteristic]

Get the inner characteristics.

Returns:: The inner characteristics.
Return type:: Sequence[Characteristic]

property explanation: str

Get the explanation.

Returns:: The explanation.
Return type:: str

property label: str

Get the label.

Returns:: The label.
Return type:: str

property name: str

Get the name.

Returns:: The name.
Return type:: str

class Property(name: str, characteristic: Optional[Characteristic] = None, **kwargs: Any)

The Property class is used to represent property characteristics.

__call__(individual: Any) → Optional[Any]

Make this characteristic callable.

Keyword Arguments:: individual (object) – Any python object
Returns:: The individual property using a property access.
Return type:: Any, optional

__init__(name: str, characteristic: Optional[Characteristic] = None, **kwargs: Any) → None

Initialise a Named instance.

Parameters:

name – A name (usually a string)

Keyword Arguments:

characteristic (Characteristic, optional) – The inner characteristic (if any)
**kwargs – Unused but useful for multi-class inheritance.

property cache: bool

Get the cache property.

Returns:: The cache property.
Return type:: bool

property characteristic: Optional[Characteristic]

Get the inner characteristic.

Returns:: The inner characteristic.
Return type:: Characteristic, optional

clear() → None: Clear the cache.

property components: Sequence[Characteristic]

Get the inner characteristics.

Returns:: The inner characteristics.
Return type:: Sequence[Characteristic]

property explanation: str

Get the explanation.

Returns:: The explanation.
Return type:: str

property label: str

Get the label.

Returns:: The label.
Return type:: str

property name: str

Get the name.

Returns:: The name.
Return type:: str

class Item(nth: int = 0, characteristic: Optional[Characteristic] = None, **kwargs: Any)

The Item class is used to represent item sequences.

Example

>>> from galactic.characteristics import Item, Key
>>> a = Item(nth=1)
>>> print(a)
~[1]
>>> a([1, 2, 3])
2
>>> a([])
>>> a = Item(nth=1, characteristic=Key(name="a"))
>>> print(a)
a[1]

__call__(individual: Any) → Optional[Any]

Make this characteristic callable.

Keyword Arguments:: individual (object) – Any python object
Returns:: The nth individual value using an array access or None if the individual does not have this nth value.
Return type:: Any, optional

__init__(nth: int = 0, characteristic: Optional[Characteristic] = None, **kwargs: Any) → None

Initialise a Item instance.

Keyword Arguments:

nth (int) – The numbering of the element in the sequence.
characteristic (Characteristic, optional) – The inner characteristic if any

property cache: bool

Get the cache property.

Returns:: The cache property.
Return type:: bool

property characteristic: Optional[Characteristic]

Get the inner characteristic.

Returns:: The inner characteristic.
Return type:: Characteristic, optional

clear() → None: Clear the cache.

property components: Sequence[Characteristic]

Get the inner characteristics.

Returns:: The inner characteristics.
Return type:: Sequence[Characteristic]

property explanation: str

Get the explanation.

Returns:: The explanation.
Return type:: str

property label: str

Get the label.

Returns:: The label.
Return type:: str

property nth: int

Get the nth value.

Returns:: The nth value.
Return type:: int

class Slice(start: Optional[int] = None, end: Optional[int] = None, characteristic: Optional[Characteristic] = None, **kwargs: Any)

The Slice class is used to represent item slices.

Example

>>> from galactic.characteristics import Slice, Key
>>> a = Slice(start=1)
>>> print(a)
~[1:]
>>> a([1, 2, 3])
[2, 3]
>>> a(None)
>>> a = Slice(start=1, characteristic=Key(name="a"))
>>> print(a)
a[1:]

__call__(individual: Any) → Optional[Any]

Make this characteristic callable.

Keyword Arguments:: individual (object) – Any python object
Returns:: The slice from start to end None if the individual does not have this value.
Return type:: Sequence[Any], optional

__init__(start: Optional[int] = None, end: Optional[int] = None, characteristic: Optional[Characteristic] = None, **kwargs: Any) → None

Initialise a Slice instance.

Keyword Arguments:

start (int, optional) – The slice start.
end (int, optional) – The slice end.
characteristic (Characteristic, optional) – The inner characteristic (if any).
**kwargs – Unused but useful for multi-class inheritance.

property cache: bool

Get the cache property.

Returns:: The cache property.
Return type:: bool

property characteristic: Optional[Characteristic]

Get the inner characteristic.

Returns:: The inner characteristic.
Return type:: Characteristic, optional

clear() → None: Clear the cache.

property components: Sequence[Characteristic]

Get the inner characteristics.

Returns:: The inner characteristics.
Return type:: Sequence[Characteristic]

property end: Optional[int]

Get the end property.

Returns:: The end property.
Return type:: int, optional

property explanation: str

Get the explanation.

Returns:: The explanation.
Return type:: str

property label: str

Get the label.

Returns:: The label.
Return type:: str

property start: Optional[int]

Get the start property.

Returns:: The start property.
Return type:: int, optional