how to include all polynomial and interaction terms

Question

I have 50 predictors in my dataset, I would like to get the second order terms and the second order interaction terms of these predictors.

Take the mtcars data set in R

Answer 1

This is almost surely a bad idea. Anyway, using the mtcars data set, after removing categorical variables

mtcars=mtcars[,1:7]
lm(as.formula(paste0("mpg~.^2+",paste0("poly(",colnames(mtcars),",2)",collapse="+")))
,data=mtcars)