formula.pdMat
Extract pdMat Formula
Description
This method function extracts the formula associated with a pdMat
object, in which the column and row names are specified.
Usage
## S3 method for class 'pdMat' formula(x, asList, ...)
Arguments
x | an object inheriting from class |
asList | logical. Should the asList argument be applied to each of the components? Never used. |
... | some methods for this generic require additional arguments. None are used in this method. |
Value
if x
has a formula
attribute, its value is returned, else NULL
is returned.
Note
Because factors may be present in formula(x)
, the pdMat
object needs to have access to a data frame where the variables named in the formula can be evaluated, before it can resolve its row and column names from the formula.
Author(s)
José Pinheiro and Douglas Bates [email protected]
See Also
Examples
pd1 <- pdSymm(~Sex*age) formula(pd1)
Copyright (©) 1999–2012 R Foundation for Statistical Computing.
Licensed under the GNU General Public License.