untangle.specials {survival5} | R Documentation |
Given a terms
structure and a desired special name, this returns an
index appropriate for subscripting the terms
structure and another
appropriate for the data frame.
untangle.specials(tt, special, order=1)
a list with two components:
# This is code from within the coxph program, m is the data frame and TT # the terms structure for the formula. We wish to exclude first order # strata() terms from the final X matrix, and also to extract these terms # to a second data frame TT <- terms(formula, specials='strata') temp <- untangle.specials(TT, 'strata') if (length(temp$vars)) { X <- model.matrix( TT[-temp$terms], m) m.strat <- m[temp$vars] } else X <- model.matrix(TT, m)