r - Passing entire data.table to j expression

Question

I want to use all columns as an object in j expression on a grouped data.table (just like tidyverse's group_modify function).

So far, I accomplished this by doing:

dt[, some_function(data.table(.SD)), some_column, .SDcols = colnames(dt)]

But this feels clunky, is there another (simpler) way to do it?

question from:https://stackoverflow.com/questions/65903597/passing-entire-data-table-to-j-expression

Answer 1

It seems that there isn't any functions in the package that present this behaviour. The way that makes the code more readable (at least for me) was by creating a wrapper function and use it:

temp_fun <- function(f, ...) {
  f(as.data.table(list(...)))
}

dt[, temp_fun(some_function, .SD), some_column]