Population

The galactic.population module.

It contains several classes for creating populations:

• DataReader class is used to read a population from a file;

• Population class is used to represent collections of individuals;

class DataReader

Data reader.

abstract classmethod extensions() → Iterator[str]

Get an iterator over the supported extensions.

Returns

An iterator over the supported extensions

Return type

Iterator[str]

abstract classmethod read(data_file: TextIO) → Iterable[Any]

Read a data file.

Keyword Arguments

data_file (FileIO) – A readable file.

Returns

An iterator over the (identifier, data) couple.

Return type

Iterator[Tuple[str, Any]]

class Population(individuals: Iterable[Any])

The Population class is used to handle collection of individuals.

It implements the Mapping abstract class from identifiers (strings) to objects.

Example

>>> from galactic.population import Population
>>> data = {"i1": {"x": 1}, "i2": {}, "i3": {"x": 1}}
>>> population = Population(data)
>>> len(population)
3
>>> list(population)
['i1', 'i2', 'i3']
>>> "i1" in population
True
>>> population.key(data["i1"])
'i1'
>>> list(population.keys())
['i1', 'i2', 'i3']
>>> list(population.values())
[{'x': 1}, {}, {'x': 1}]

Example

>>> from galactic.population import Population
>>> data = [{"x": 1}, {}, {"x": 1}]
>>> population = Population(data)
>>> len(population)
3
>>> list(population)
['0', '1', '2']
>>> "0" in population
True
>>> population.key(data[0])
'0'
>>> list(population.keys())
['0', '1', '2']
>>> list(population.values())
[{'x': 1}, {}, {'x': 1}]

__init__(individuals: Iterable[Any])

Initialise a Population instance.

If the individuals argument is a mapping, their identifiers will be the string conversion of their keys.

If the individuals argument is an collection, their identifiers will be the string conversion of their positions.

Keyword Arguments

individuals (Union[Mapping, Iterable]) – An iterable of individuals.

Raises

TypeError – If the individuals argument is not an instance of Union[Mapping, Iterable].

classmethod from_file(stream: TextIO) → galactic.population.Population

Create a population from a readable opened file.

Keyword Arguments

stream (TextIO) – File to read

Returns

A new population

Return type

Population

get(k[, d]) → D[k] if k in D, else d.  d defaults to None.

index(individual: Any) → int

Get the index of an individual.

Parameters

individual – The individual whose index is requested.

Returns

Return type

The index of the individual.

Raises

ValueError – If the individual does not belong to the population.

items() → a set-like object providing a view on D’s items

key(individual: Any) → str

Get the identifier of an individual.

Parameters

individual – The individual whose identifier is requested.

Returns

Return type

The identifier of the individual.

Raises

ValueError – If the individual does not belong to the population.

keys() → a set-like object providing a view on D’s keys

classmethod readers() → Iterator[galactic.population.DataReader]

Get all the registered data reader plugins.

Returns

An iterator on registered data reader plugins.

Return type

Iterator[DataReader]

classmethod register_reader(reader: galactic.population.DataReader) → None

Register a new reader.

Parameters

reader (DataReader) – The reader

values() → an object providing a view on D’s values