Take a formula and return a vector of the variables on the left hand side, it will return NULL for a one sided formula
Examples
ff <- yvar ~ x1 + x2
lhs.vars(ff)
#> [1] "yvar"
Take a formula and return a vector of the variables on the left hand side, it will return NULL for a one sided formula
ff <- yvar ~ x1 + x2
lhs.vars(ff)
#> [1] "yvar"