Characteristics¶

The galactic.characteristics module defines characteristics.

Characteristic for the superclass of all 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: galactic.characteristics.Characteristic, cache: bool = True, label: Optional[str] = None, explanation: Optional[str] = None)¶

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: Optional[Any]

Hint

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

__init__(*components: galactic.characteristics.Characteristic, cache: bool = True, label: Optional[str] = None, explanation: Optional[str] = None) → None ¶

Initialise a Characteristic instance.

Parameters

*components – Inner characteristics (if any).

Keyword Arguments

cache (bool) – Is this characteristic is cached?
label (Optional[str]) – An optional label.
explanation (Optional[str]) – An optional explanation in markdown text.

property cache¶

Get the cache property.

Returns: The cache property.
Return type: bool

clear() → None ¶: Clear the cache.

property components¶

Get the inner characteristics.

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

property explanation¶

Get the explanation.

Returns: The strategy explanation.
Return type: Optional[str]

property label¶

Get the label.

Returns: The strategy label.
Return type: Optional[str]

class Named(name: str, characteristic: Optional[galactic.characteristics.Characteristic] = None, **kwargs: Any)¶

The Named class is used to represent named characteristics.

Is is designed for subclassing.

__init__(name: str, characteristic: Optional[galactic.characteristics.Characteristic] = None, **kwargs: Any) → None ¶

Initialise a Named instance.

Parameters

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

Keyword Arguments

name – A name (usually a string)

property cache¶

Get the cache property.

Returns: The cache property.
Return type: bool

property characteristic¶

Get the inner characteristic.

Returns: The inner characteristic.
Return type: Characteristic

clear() → None ¶: Clear the cache.

property components¶

Get the inner characteristics.

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

property explanation¶

Get the explanation.

Returns: The strategy explanation.
Return type: Optional[str]

property label¶

Get the label.

Returns: The strategy label.
Return type: Optional[str]

property name¶

Get the name.

Returns: The name.
Return type: str

class Key(name: str, characteristic: Optional[galactic.characteristics.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

__init__(name: str, characteristic: Optional[galactic.characteristics.Characteristic] = None, **kwargs: Any) → None ¶

Initialise a Named instance.

Parameters

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

Keyword Arguments

name – A name (usually a string)

property cache¶

Get the cache property.

Returns: The cache property.
Return type: bool

property characteristic¶

Get the inner characteristic.

Returns: The inner characteristic.
Return type: Characteristic

clear() → None ¶: Clear the cache.

property components¶

Get the inner characteristics.

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

property explanation¶

Get the explanation.

Returns: The strategy explanation.
Return type: Optional[str]

property label¶

Get the label.

Returns: The strategy label.
Return type: Optional[str]

property name¶

Get the name.

Returns: The name.
Return type: str

class Property(name: str, characteristic: Optional[galactic.characteristics.Characteristic] = None, **kwargs: Any)¶

The Property class is used to represent property characteristics.

__init__(name: str, characteristic: Optional[galactic.characteristics.Characteristic] = None, **kwargs: Any) → None ¶

Initialise a Named instance.

Parameters

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

Keyword Arguments

name – A name (usually a string)

property cache¶

Get the cache property.

Returns: The cache property.
Return type: bool

property characteristic¶

Get the inner characteristic.

Returns: The inner characteristic.
Return type: Characteristic

clear() → None ¶: Clear the cache.

property components¶

Get the inner characteristics.

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

property explanation¶

Get the explanation.

Returns: The strategy explanation.
Return type: Optional[str]

property label¶

Get the label.

Returns: The strategy label.
Return type: Optional[str]

property name¶

Get the name.

Returns: The name.
Return type: str

class Item(nth: int = 0, characteristic: Optional[galactic.characteristics.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]

__init__(nth: int = 0, characteristic: Optional[galactic.characteristics.Characteristic] = None, **kwargs: Any) → None ¶

Initialise a Item instance.

Keyword Arguments

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

property cache¶

Get the cache property.

Returns: The cache property.
Return type: bool

property characteristic¶

Get the inner characteristic.

Returns: The inner characteristic.
Return type: Characteristic

clear() → None ¶: Clear the cache.

property components¶

Get the inner characteristics.

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

property explanation¶

Get the explanation.

Returns: The strategy explanation.
Return type: Optional[str]

property label¶

Get the label.

Returns: The strategy label.
Return type: Optional[str]

property nth¶

Get the nth value.

Returns: The nth value.
Return type: int

class Slice(start: Optional[int] = None, end: Optional[int] = None, characteristic: Optional[galactic.characteristics.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:]

__init__(start: Optional[int] = None, end: Optional[int] = None, characteristic: Optional[galactic.characteristics.Characteristic] = None, **kwargs: Any) → None ¶

Initialise a Slice instance.

Keyword Arguments

start (int) – The slice start.
end (int) – The slice end.
characteristic (Characteristic) – The inner characteristic (if any).

property cache¶

Get the cache property.

Returns: The cache property.
Return type: bool

property characteristic¶

Get the inner characteristic.

Returns: The inner characteristic.
Return type: Characteristic

clear() → None ¶: Clear the cache.

property components¶

Get the inner characteristics.

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

property end¶

Get the end property.

Returns: The end property.
Return type: Optional[int]

property explanation¶

Get the explanation.

Returns: The strategy explanation.
Return type: Optional[str]

property label¶

Get the label.

Returns: The strategy label.
Return type: Optional[str]

property start¶

Get the start property.

Returns: The start property.
Return type: Optional[int]