Parameters

Handle legislative parameters.

class openfisca_core.parameters.Bracket(name=u'', directory_path=None, data=None, file_path=None)

A scale bracket.

class openfisca_core.parameters.Parameter(name, data, file_path=None)

A parameter of the legislation. Parameters can change over time.

Parameters:

• name (string) – Name of the parameter, e.g. “taxes.some_tax.some_param”
• data (dict) – Data loaded from a YAML file.
• file_path (string) – File the parameter was loaded from.
• documentation (string) – Documentation describing parameter usage and context.

Instantiate a parameter without metadata:

>>>  Parameter('rate', data = {
        "2015-01-01": 550,
        "2016-01-01": 600
        })

Instantiate a parameter with metadata:

>>>  Parameter('rate', data = {
        'description': 'Income tax rate applied on salaries',
        'values': {
            "2015-01-01": {'value': 550, 'metadata': {'reference': 'http://taxes.gov/income_tax/2015'}},
            "2016-01-01": {'value': 600, 'metadata': {'reference': 'http://taxes.gov/income_tax/2016'}}
            }
        })

values_list

List of the values, in reverse chronological order

update(period=None, start=None, stop=None, value=None)

Change the value for a given period.

Parameters:

• period – Period where the value is modified. If set, start and stop should be None.
• start – Start of the period. Instance of openfisca_core.periods.Instant. If set, period should be None.
• stop – Stop of the period. Instance of openfisca_core.periods.Instant. If set, period should be None.
• value – New value. If None, the parameter is removed from the legislation parameters for the given period.

class openfisca_core.parameters.ParameterAtInstant(name, instant_str, data=None, file_path=None, metadata=None)

A value of a parameter at a given instant.

class openfisca_core.parameters.ParameterNode(name=u'', directory_path=None, data=None, file_path=None)

A node in the legislation parameter tree.

add_child(name, child)

Add a new child to the node.

Parameters:

• name – Name of the child that must be used to access that child. Should not contain anything that could interfere with the operator . (dot).
• child – The new child, an instance of Scale or Parameter or ParameterNode.

get_descendants()

Return a generator containing all the parameters and nodes recursively contained in this ParameterNode

merge(other)

Merges another ParameterNode into the current node.

In case of child name conflict, the other node child will replace the current node child.

class openfisca_core.parameters.ParameterNodeAtInstant(name, node, instant_str)

Parameter node of the legislation, at a given instant.

exception openfisca_core.parameters.ParameterNotFound(name, instant_str, variable_name=None)

Exception raised when a parameter is not found in the parameters.

exception openfisca_core.parameters.ParameterParsingError(message, file=None, traceback=None)

Exception raised when a parameter cannot be parsed.

class openfisca_core.parameters.Scale(name, data, file_path)

A parameter scale (for instance a marginal scale).

class openfisca_core.parameters.VectorialParameterNodeAtInstant(name, vector, instant_str)

Parameter node of the legislation at a given instant which has been vectorized. Vectorized parameters allow requests such as parameters.housing_benefit[zipcode], where zipcode is a vector

static check_node_vectorisable(node)

Check that a node can be casted to a vectorial node, in order to be able to use fancy indexing.

openfisca_core.parameters.load_parameter_file(file_path, name=u'')

Load parameters from a YAML file (or a directory containing YAML files).

Returns:An instance of ParameterNode or Scale or Parameter.