How to reliably get dependent variable name from formula object?

Question

Let\'s say I have the following formula:

myformula<-formula(\"depVar ~ Var1 + Var2\")

How to reliably get dependent variable name from formu

Answer 1

I know this question is quite old, but I thought I'd add a base R answer which doesn't require indexing, doesn't depend on the order of the variables listed in a call to all.vars, and which gives the response variables as separate elements when there is more than one:

myformula <- formula("depVar1 + depVar2 ~ Var1 + Var2")
all_vars <- all.vars(myformula)
response <- all_vars[!(all_vars %in% labels(terms(myformula)))]

> response
[1] "depVar1" "depVar2"