Adding column if it does not exist

Question

I have a bunch of data frames with different variables. I want to read them into R and add columns to those that are short of a few variables so that they all have a common

Answer 1

We could create a helper function to create the column

fncols <- function(data, cname) {
  add <-cname[!cname%in%names(data)]

  if(length(add)!=0) data[add] <- NA
  data
}
fncols(mtcars, "mpg")
fncols(mtcars, c("topspeed","nhj","mpg"))