How do I pass names for new summary columns to data.table in a function?

Question

Say I want to create a function that calculates a summary dataset from a data.table in R, and I want to be able to pass the name of the new calculated variable in programmat

Answer 1

You could consider changing the column names inside your function:

groupMeans <- function(out.var, by.var, dat = dt) {
  res <- dat[, list(mean(x)), by=by.var]
  setnames(res, "V1", out.var)
  res
}