How to create a loop to check number of levels for every variable?

Question

I'm a newbie to rstudio, and I'm stuck on this part cleaning the data. So basically I need to remove all variables with nlevels <=2, then forming a cleaned new data. I want to create an if else statement that does this for me. How should I do it? The data I'm trying to clean is called "full_clean", I wrote the code below but it wouldn't run and looks very messy. Thanks in advance!

for (i in 1:ncol(full_clean)){
  if(nlevels(as.factor(lapply((head(full_clean,n=0)[2],factor))))){
    full_clean <- select(full_clean, -colnames(full_clean[i]))
  }
}