API Reference#
This reference provides detailed documentation for all modules, classes, and methods in the current release of formulae.
formulae
#
- formulae.design_matrices(formula, data, na_action='drop', env=0, extra_namespace=None)[source]#
Parse model formula and obtain a
DesignMatrices
object containing objects representing the response and the design matrices for both the common and group specific effects.- Parameters
formula (string) – A model formula.
data (pandas.DataFrame) – The data frame where variables in the formula are taken from.
na_action (string) – Describes what to do with missing values in
data
."drop"
means to drop all rows with a missing value,"error"
means to raise an error,"pass"
means to to keep all. Defaults to"drop"
.env (integer) – The number of environments we walk up in the stack starting from the function’s caller to capture the environment where formula is evaluated. Defaults to 0 which means the evaluation environment is the environment where
design_matrices
is called.extra_namespace (dict) – Additional user supplied transformations to include in the environment where the formula is evaluated. Defaults to
None
.
- Returns
design – An instance of DesignMatrices that contains the design matrice(s) described by
formula
.- Return type
- formulae.model_description(formula)[source]#
Interpret model formula and obtain a model description.
This function receives a string with a formula describing a statistical model and returns an object of class ModelTerms that describes the model interpreted from the formula.
- Parameters
formula (string) – A string with a model description in formula language.
- Return type
An object of class ModelTerms with an internal description of the model.
formulae.matrices
#
- class formulae.matrices.DesignMatrices(model, data, env)[source]#
A wrapper of the response, the common, and group specific effects.
- Parameters
model (Model) – The model description, the result of calling
model_description
.data (pandas.DataFrame) – The data frame where variables are taken from.
env (Environment) – The environment where values and functions are taken from.
- response#
The response in the model. Access its values with
self.response.design_matrix
. It isNone
if there is no response term in the model.- Type
- common#
The common effects (a.k.a. fixed effects) in the model. The design matrix can be accessed with
self.common.design_matrix
. The submatrix for a term is accessed viaself.common[term_name]
. It isNone
if there are no common terms in the model.- Type
- group#
The group specific effects (a.k.a. random effects) in the model. The design matrix can be accessed with
self.group.design_matrix
. The submatrix for a term is accessed viaself.group[term_name]
. It isNone
if there are no group specific terms in the model.- Type