Define the strata in a dataset to match those of a stratified Cox model
coxStrata(object, data, sterms, strata.vars, strata.levels)# S3 method for cph
coxStrata(object, data, sterms, strata.vars, strata.levels)
# S3 method for coxph
coxStrata(object, data, sterms, strata.vars, strata.levels)
# S3 method for phreg
coxStrata(object, data, sterms, strata.vars, strata.levels)
The fitted Cox regression model object either
obtained with coxph
(survival package), cph
(rms package), or phreg
(mets package).
a data.frame
or a data.table
terms in the formula corresponding to the strata variables
the name of the variables used to define the strata
a named list containing for each variable used to form the strata all its possible levels
the strata levels that have been used to fit the Cox model
if no strata variables returns a vector of "1"
(factor).