Question

I have a data.frame, df, with n variables in it. The variables can take any name.

I want to be able to fit coxph(Surv(time_to_event,bad_outcome)~var1+var2+…+varn,data=df)

But df is a variable, its length can change. How do I write a piece of code that can fit all the variables in df regardless of the number of variables in df and the names of the variables?

Thank you so much.

Answer 1

Read ?formula:

There are two special interpretations
of ‘.’ in a formula. The usual one is
in the context of a ‘data’ argument of
model fitting functions and means ‘all
columns not otherwise in the formula’:
see ‘terms.formula’. In the context
of ‘update.formula’, only, it means
‘what was previously in this part of
the formula’.