model.matrix.coxph
Model.matrix method for coxph models
Description
Reconstruct the model matrix for a cox model.
Usage
## S3 method for class 'coxph' model.matrix(object, data=NULL, contrast.arg = object$contrasts, ...)
Arguments
object | the result of a |
data | optional, a data frame from which to obtain the data |
contrast.arg | optional, a contrasts object describing how factors should be coded |
... | other possible argument to |
Details
When there is a data
argument this function differs from most of the other model.matrix
methods in that the response variable for the original formula is not required to be in the data.
If the data frame contains a terms
attribute then it is assumed to be the result of a call to model.frame
, otherwise a call to model.frame
is applied with the data as an argument.
Value
The model matrix for the fit
Author(s)
Terry Therneau
See Also
Examples
fit1 <- coxph(Surv(time, status) ~ age + factor(ph.ecog), data=lung) xfit <- model.matrix(fit1) fit2 <- coxph(Surv(time, status) ~ age + factor(ph.ecog), data=lung, x=TRUE) all.equal(model.matrix(fit1), fit2$x)
Copyright (©) 1999–2012 R Foundation for Statistical Computing.
Licensed under the GNU General Public License.