Characteristics¶

The galactic.characteristics module defines essential classes for representing characteristics:

Characteristic for the superclass of all characteristics
Valued for characteristics defined by a data
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
Transformation for characteristics that hold a transform operation
Composite for characteristics which contain a collection of other Characteristic instances
Conversion for characteristics that execute a transform operation
Sum for characteristics that execute a sum operation
Comparison for characteristics that need a strict boolean flag used in comparison
Set for characteristics that contains a set of values

class galactic.characteristics.Characteristic(*args, **kwargs)¶

Bases: typing.Callable

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=None)¶

Make this characteristic callable. This method should be overridden in sub-classes.

Keyword Arguments: individual – Any python object
Returns: The individual characteristic
Return type: object

galactic.characteristics.identity = <galactic.characteristics.Characteristic object>¶: The identity characteristic.

class galactic.characteristics.Valued(*args, data=None, **kwargs)¶

Bases: galactic.characteristics.Characteristic

The Valued class is used to hold a data.

data¶: The data hold by the instance.

Example

>>> from galactic.characteristics import Valued
>>> a = Valued(data=5)
>>> print(a)
5
>>> a({})
5
>>>

__init__(*args, data=None, **kwargs)¶

Initialise a Valued instance.

Parameters

*args – Unused but useful for multi-class inheritance.
**kwargs – Unused but useful for multi-class inheritance.

Keyword Arguments

data – Any python object

__call__(individual=None)¶

Make this characteristic callable.

Keyword Arguments: individual – Any python object
Returns: The data hold by this individual.
Return type: object

class galactic.characteristics.Named(*args, name=None, **kwargs)¶

Bases: galactic.characteristics.Characteristic

The Named class is used to represent named characteristics. Is is designed for subclassing.

name¶

The name hold by the instance. It is used to name Characteristic instances.

Type: str

__init__(*args, name=None, **kwargs)¶

Initialise a Named instance.

Parameters

*args – Unused but useful for multi-class inheritance.
**kwargs – Unused but useful for multi-class inheritance.

Keyword Arguments

name – A name (usually a string)

class galactic.characteristics.Composite(*args, **kwargs)¶

Bases: galactic.characteristics.Characteristic

The Composite class is used as a container of embedded Characteristic instances. It is designed for subclassing.

characteristics¶

The tuple of Characteristic instances hold by this instance.

Type: tuple

__init__(*args, **kwargs)¶

Initialise a Composite instance.

Parameters

*args (tuple) – A collection of Characteristic instances
**kwargs – Unused but useful for multi-class inheritance.

Raises

TypeError – If a characteristic is not an instance of Characteristic

class galactic.characteristics.Key(characteristic: galactic.characteristics.Characteristic = <galactic.characteristics.Characteristic object>, **kwargs)¶

Bases: galactic.characteristics.Named, galactic.characteristics.Composite

The Key class is used to represent key characteristics.

name¶

The name hold by the instance.

Type: str

characteristics¶

The tuple of Characteristic instances hold by this instance.

Type: tuple

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"))
>>> a({"x": {"y": 5}})
5

__init__(characteristic: galactic.characteristics.Characteristic = <galactic.characteristics.Characteristic object>, **kwargs)¶

Initialize a Key instance.

Keyword Arguments: characteristic (Characteristic) – The underlying characteristic.

__call__(individual=None)¶

Make this characteristic callable.

Keyword Arguments: individual – Any python object
Returns: The individual key using an array access or None if the individual does not have this key.
Return type: object

class galactic.characteristics.Property(characteristic: galactic.characteristics.Characteristic = <galactic.characteristics.Characteristic object>, **kwargs)¶

Bases: galactic.characteristics.Named, galactic.characteristics.Composite

The Property class is used to represent property characteristics.

name¶

The name hold by the instance.

Type: str

characteristics¶

The tuple of Characteristic instances hold by this instance.

Type: tuple

__init__(characteristic: galactic.characteristics.Characteristic = <galactic.characteristics.Characteristic object>, **kwargs)¶

Initialize a Property instance.

Keyword Arguments: characteristic (Characteristic) – The underlying characteristic.

__call__(individual=None)¶

Make this characteristic callable.

Keyword Arguments: individual – Any python object
Returns: The individual property using a property access or None if the individual does not have this property.
Return type: object

class galactic.characteristics.Transformation(*args, transform=<function Transformation.<lambda>>, **kwargs)¶

Bases: galactic.characteristics.Characteristic

The Transformation class is used to hold a transform operation. It is designed for subclassing.

transform¶

The transform operation hold by the instance. It is used to apply transformation on values.

Type: Callable

__init__(*args, transform=<function Transformation.<lambda>>, **kwargs)¶

Initialise a Transformation instance.

Parameters

*args – Unused but useful for multi-class inheritance.
**kwargs – Unused but useful for multi-class inheritance.

Keyword Arguments

transform – A transform operation.

class galactic.characteristics.Conversion(characteristic: galactic.characteristics.Characteristic, **kwargs)¶

Bases: galactic.characteristics.Composite, galactic.characteristics.Transformation, galactic.characteristics.Valued

The Conversion class is used to convert a characteristic call to a specific type.

characteristics¶

The characteristics (tuple of Characteristic instances) hold by this instance.

Type: tuple

transform¶

The transform operation hold by the instance.

Type: Callable

data¶: The data hold by the instance.

Example

>>> from galactic.characteristics import Conversion, Key
>>> a = Conversion(Key(name="x"), transform=float, data="nan")
>>> print(a)
x
>>> a({"x": "5"})
5.0
>>> a(4)
nan

__init__(characteristic: galactic.characteristics.Characteristic, **kwargs)¶

Initialise a Conversion instance.

Parameters

characteristic (Characteristic) – The embedded characteristics

Keyword Arguments

transform (Callable) – A transform operation (inherited from Transformation.__init__()).
data – Any python object (inherited from Valued.__init__()).

__call__(individual=None)¶

Make this characteristic callable.

Keyword Arguments: individual – Any python object
Returns: the individual data converted by the transform operation or the default transformed data if a TypeError or a ValueError is raised.
Return type: object

class galactic.characteristics.Sum(*args, start=0, **kwargs)¶

Bases: galactic.characteristics.Composite, galactic.characteristics.Transformation, galactic.characteristics.Valued

The Sum class is used to define a sum over other Characteristic instances.

start¶: Initial value for the sum. It is used as a beginning for the sum calculus.

characteristics¶

The characteristics (tuple of Characteristic instances) hold by this instance.

Type: tuple

transform¶

The transform operation hold by the instance.

Type: Callable

data¶: The data hold by the instance.

Example

>>> from galactic.characteristics import Key, Sum
>>> s = Sum(Key(name="x"), Key(name="y"), start=[], data=None)
>>> print(s)
(x+y)
>>> s({})
>>> s({"x": [1]})
>>> s({"x": [1], "y": [2]})
[1, 2]
>>>

Example

>>> from galactic.characteristics import Key, Sum
>>> s = Sum(Key(name="x"), Key(name="y"), start=0, data="nan", transform=float)
>>> print(s)
(x+y)
>>> s({})
nan
>>> s({"x": 1})
nan
>>> s({"x": 1, "y": 2})
3.0
>>>

__init__(*args, start=0, **kwargs)¶

Initialise a Sum instance.

Parameters

*args (tuple) – A collection of Characteristic instances to sum (inherited from Composite.__init__())
**kwargs – Unused but useful for multi-class inheritance.

Keyword Arguments

start – Initial data for the sum
transform (Callable) – A transform operation (inherited from Transformation.__init__()).
data – Any python object (inherited from Valued.__init__()).

__call__(individual=None)¶

Make this characteristic callable.

Parameters: individual – Any python object
Returns: the sum of all Characteristic instance calls on the individual or the default transformed data if a TypeError or a ValueError is raised.
Return type: object

class galactic.characteristics.Comparison(*args, strict=False, **kwargs)¶

Bases: galactic.characteristics.Characteristic

The Comparison class can be inherited to hold strict property. It is designed for subclassing.

strict¶

The strict property hold by this instance. It is a boolean flag used for strict (or not) Comparison.

Type: bool

__init__(*args, strict=False, **kwargs)¶

Initialise a Comparison instance.

Parameters

*args – Unused but useful for multi-class inheritance.
**kwargs – Unused but useful for multi-class inheritance.

Keyword Arguments

strict – Is the comparison strict?

class galactic.characteristics.Set(*args, values=None, **kwargs)¶

Bases: galactic.characteristics.Characteristic

A Set characteristics can be inherited to hold a set of values property. It is designed for subclassing.

values¶

The values hold by this instance. It is used to hold a collection of values.

Type: Container

__init__(*args, values=None, **kwargs)¶

Initialise a Set instance.

Parameters

*args – Unused but useful for multi-class inheritance.
**kwargs – Unused but useful for multi-class inheritance.

Keyword Arguments

values (Container, Hashable) – A container to be compared with

Raises

TypeError – If the values argument is not an instance of Container
TypeError – If the values argument is not an instance of Hashable

galactic.characteristics.get_classes()¶

Get all classes defined in this module.

Returns: dict – A mapping from names to classes.
Return type: dict