formulas {lme4} | R Documentation |
These generic functions extract sub-formulas or values of components from a formula/data pair.
getCovariate(object, form, data) getCovariateFormula(object) getGroups(object, form, level, data, sep, ...) getGroupsFormula(object, asList, sep) getResponse(object, form) getResponseFormula(object) subFormula(form, pos) splitFormula(form, sep)
object |
a formula or an object that can provide a formula |
form |
an optional formula with a conditioning expression on its
right hand side (i.e. an expression involving the |
operator). Defaults to formula(object) . |
level |
a positive integer vector with the level(s) of grouping to be used when multiple nested levels of grouping are present. This argument is optional for most methods of this generic function and defaults to all levels of nesting. |
data |
a data frame in which to interpret the variables named in
form . Optional for most methods. |
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. Defaults to '/' . |
pos |
the integer index of the component of the formula to
return. Defaults to 2 . |
... |
Optional arguments that are passed to some methods. None used at present. |
getGroupsFormula
returns a one-sided formula, or a list of
one-sided formulas, giving the grouping structure associated with
formula(object)
. If no conditioning expression is present in
formula(object)
a NULL
value is returned.
form = resp ~ cov1 + cov2 | grp1/grp2 getResponseFormula(form) getCovariateFormula(form) getGroupsFormula(form) getGroupsFormula(form, asList = TRUE)