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.
getGroupsFormula(object, asList, sep)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.
any object from which a formula can be extracted.
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.
character, the separator to use between group levels when
multiple levels are collapsed. The default is '/'.
José Pinheiro and Douglas Bates bates@stat.wisc.edu
getGroupsFormula.gls,
getGroupsFormula.lmList,
getGroupsFormula.lme,
getGroupsFormula.reStruct,
getGroups
getGroupsFormula(y ~ x | g1/g2)
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