nlme: getGroupsFormula – R documentation

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getGroupsFormula

Extract Grouping Formula

Description

The conditioning expression associated with formula(object) (i.e. the expression after the | operator) is returned either as a named list of one-sided formulas, or a single one-sided formula, depending on the value of asList. The components of the returned list are ordered from outermost to innermost level and are named after the grouping factor expression.

Usage

getGroupsFormula(object, asList, sep)

Arguments

`object`	any object from which a formula can be extracted.
`asList`	an optional logical value. If `TRUE` the returned value with be a list of formulas; else, if `FALSE` the returned value will be a one-sided formula. Defaults to `FALSE`.
`sep`	character, the separator to use between group levels when multiple levels are collapsed. The default is `'/'`.

Value

a one-sided formula, or a list of one-sided formulas, with the grouping structure associated with formula(object). If no conditioning expression is present in formula(object) a NULL value is returned.

Author(s)

José Pinheiro and Douglas Bates bates@stat.wisc.edu

Examples

getGroupsFormula(y ~ x | g1/g2)

nlme

Linear and Nonlinear Mixed Effects Models

v3.1-152

GPL (>= 2) | file LICENCE

Authors

José Pinheiro [aut] (S version), Douglas Bates [aut] (up to 2007), Saikat DebRoy [ctb] (up to 2002), Deepayan Sarkar [ctb] (up to 2005), EISPACK authors [ctb] (src/rs.f), Siem Heisterkamp [ctb] (Author fixed sigma), Bert Van Willigen [ctb] (Programmer fixed sigma), Johannes Ranke [ctb] (varConstProp()), R-core [aut, cre]

Initial release

2021-02-03