Extract lmList Object Grouping Formula

DESCRIPTION:

A formula representing the grouping factor determining the partitioning of the observations used to produce the lm components of object is obtained and returned as a list with a single component, or as a one-sided formula.

USAGE:

getGroupsFormula(object, asList) 

REQUIRED ARGUMENTS:

object
an object inheriting from class lmList, representing a list of lm objects with a common model.

OPTIONAL ARGUMENTS:

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.

VALUE:

a one-sided formula, or a list with a single one-sided formula, representing the grouping factor corresponding to the lm components of object.

SEE ALSO:

,

EXAMPLES:

fm1 <- lmList(distance ~ age | Subject, Orthodont) 
getGroupsFormula(fm1)