Variables#

The policyengine_core.variables module contains the definition of Variable, which can have a value for each entity instance in a simulation, for each period in a simulation, dependent on the parameters in that period, as well as other entity instances.

Variable#

class policyengine_core.variables.variable.Variable(baseline_variable=None)[source]#

Bases: object

A variable of the legislation.

adds: List[str] = None#: List of variables that are added to the variable. Alternatively, can be a parameter name.

baseline_variable: str#

//openfisca.org/doc/key-concepts/reforms.html>`_ to replace another variable, baseline_variable is the replaced variable.

Type:: If the variable has been introduced in a `reform <https

default_value: object#

//openfisca.org/doc/key-concepts/variables.html#default-values>`_ of the variable.

Type:: `Default value <https

defined_for: str = None#: The name of another variable, nonzero values of which are used to define the set of entities for which this variable is defined.

definition_period: str#

MONTH, YEAR, ETERNITY.

Type:: `Period <https
Type:: //openfisca.org/doc/coding-the-legislation/35_periods.html>`_ the variable is defined for. Possible value

documentation: str#: Free multilines text field describing the variable context and usage.

dtype: dtype#

//docs.scipy.org/doc/numpy-1.13.0/reference/generated/numpy.dtype.html>`_ used under the hood for the variable.

Type:: Numpy `dtype <https

end: date#

//openfisca.org/doc/coding-the-legislation/40_legislation_evolutions.html#variable-end>`_ when the variable disappears from the legislation.

Type:: `Date <https

entity: Entity#

Person, Household.

Type:: `Entity <https
Type:: //openfisca.org/doc/key-concepts/person,_entities,_role.html>`_ the variable is defined for. For instance

exhaustive_parameter_dependencies: List[str] = None#: If these parameters (plus the dataset, branch and period) haven’t changed, Core will use caching on this variable.

formulas: List[Callable]#: Formulas used to calculate the variable

get_formula(period=None)[source]#

Returns the formula used to compute the variable at the given period.

If no period is given and the variable has several formula, return the oldest formula.

Returns:: Formula used to compute the variable

classmethod get_introspection_data(tax_benefit_system)[source]#

Get instrospection data about the code of the variable.

Returns:: (comments, source file path, source code, start line number)
Return type:: tuple

hidden_input: bool = False#: Whether the variable is hidden from the input screen entirely on PolicyEngine.

index_in_module: int = None#: Index of the variable in the module it is defined in.

is_input_variable()[source]#: Returns True if the variable is an input variable.

is_neutralized: bool#: True if the variable is neutralized. Neutralized variables never use their formula, and only return their default values when calculated.

json_type: str#: JSON type corresponding to the variable.

label: str#: Description of the variable

max_length: int#: If the value type of the variable is str, max length of the string allowed. None if there is no limit.

max_value: (<class 'float'>, <class 'int'>) = None#: Maximum value of the variable.

metadata: dict = None#: Free dictionary field used to store any metadata.

min_value: (<class 'float'>, <class 'int'>) = None#: Minimum value of the variable.

module_name: str = None#: The name of the module it is defined in.

name: str#: Name of the variable

parse_formula_name(attribute_name)[source]#

Returns the starting date of a formula based on its name.

Valid dated name formats are : ‘formula’, ‘formula_YYYY’, ‘formula_YYYY_MM’ and ‘formula_YYYY_MM_DD’ where YYYY, MM and DD are a year, month and day.

By convention, the starting date of:

formula is 0001-01-01 (minimal date in Python)
formula_YYYY is YYYY-01-01
formula_YYYY_MM is YYYY-MM-01

possible_values: EnumArray#: If the value type of the variable is Enum, contains the values the variable can take.

quantity_type: str#: Categorical attribute describing whether the variable is a stock or a flow.

reference: str#: Legislative reference describing the variable.

requires_computation_after: str = None#: Name of a variable that must be computed before this variable.

set_input: Callable#

//openfisca.org/doc/coding-the-legislation/35_periods.html#set-input-automatically-process-variable-inputs-defined-for-periods-not-matching-the-definition-period>`_. Possible values are set_input_dispatch_by_period, set_input_divide_by_period, or nothing.

Type:: Function used to automatically process variable inputs defined for periods not matching the definition_period of the variable. See more on the `documentation <https

subtracts: List[str] = None#: List of variables that are subtracted from the variable. Alternatively, can be a parameter name.

unit: str#: Free text field describing the unit of the variable. Only used as metadata.

uprating: str = None#: Name of a parameter used to uprate the variable.

value_type: type#: The value type of the variable. Possible value types in OpenFisca are int float bool str date and Enum.