How do I fit a model without specifying the number of variables?

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’.