| getGroups {nlme} | R Documentation |
Extract Grouping Factors from an Object
Description
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.
Usage
getGroups(object, form, level, data, sep)
Arguments
object |
any object |
form |
an optional formula with a conditioning expression on its
right hand side (i.e. an expression involving the |
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
|
sep |
character, the separator to use between group levels when
multiple levels are collapsed. The default is |
Value
will depend on the method function used; see the appropriate documentation.
Author(s)
José Pinheiro and Douglas Bates bates@stat.wisc.edu
References
Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer, esp. pp. 100, 461.
See Also
getGroupsFormula, getGroups.data.frame,
getGroups.gls, getGroups.lmList,
getGroups.lme
Examples
## see the method function documentation