getGroups {nlme}R Documentation

Extract Grouping Factors from an Object


This function is generic; method functions can be written to handle specific classes of objects. Classes which already have methods for this function include corStruct, data.frame, gls, lme, lmList, and varFunc.


getGroups(object, form, level, data, sep)


object any object
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.
sep character, the separator to use between group levels when multiple levels are collapsed. The default is '/'.


will depend on the method function used; see the appropriate documentation.


Jose Pinheiro and Douglas Bates

See Also

getGroupsFormula,, getGroups.gls, getGroups.lmList, getGroups.lme


## see the method function documentation

[Package nlme version 3.1-57 Index]