Variables¶

class openfisca_core.variables.Variable(baseline_variable=None)[source]¶

A variable of the legislation.

Main attributes:

name¶

Name of the variable

value_type¶

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

entity¶

Entity the variable is defined for. For instance : Person, Household.

definition_period¶

Period the variable is defined for. Possible value: DateUnit.DAY, DateUnit.MONTH, DateUnit.YEAR, DateUnit.ETERNITY.

formulas¶

Formulas used to calculate the variable

label¶

Description of the variable

reference¶

Legislative reference describing the variable.

default_value¶

Default value of the variable.

Secondary attributes:

baseline_variable¶

If the variable has been introduced in a reform to replace another variable, baseline_variable is the replaced variable.

dtype¶

Numpy dtype used under the hood for the variable.

end¶

Date when the variable disappears from the legislation.

is_neutralized¶

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

json_type¶

JSON type corresponding to the variable.

max_length¶

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

possible_values¶

If the value type of the variable is Enum, contains the values the variable can take.

set_input¶

Function used to automatically process variable inputs defined for periods not matching the definition_period of the variable. See more on the documentation. Possible values are set_input_dispatch_by_period, set_input_divide_by_period, or nothing.

unit¶

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

documentation¶

Free multilines text field describing the variable context and usage.

get_formula(period=None)[source]¶

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

If no period is given and the variable has several formulas, the method returns the oldest formula.

Parameters:: period (Union[Instant, Period, str, int]) – The period to get the formula.
Return type:: Optional[Formula]
Returns:: Formula used to compute the variable.

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

openfisca_core.variables.helpers.get_annualized_variable(variable, annualization_period=None)[source]¶

Returns a clone of variable that is annualized for the period annualization_period. When annualized, a variable’s formula is only called for a January calculation, and the results for other months are assumed to be identical.

Return type:: Variable

openfisca_core.variables.helpers.get_neutralized_variable(variable)[source]¶: Return a new neutralized variable (to be used by reforms). A neutralized variable always returns its default value, and does not cache anything.