R: Added import(data.table) to NAMESPACE automatically using devtools

问题

How do I correctly add import(data.table) to the NAMESPACE file automatically using devtools?

Generally if my packages use data.table I just write it in manually, but then I can't use @export and devtools::document to create the NAMESPACE file properly, as it either overwrites the addition I've made, or doesn't update the file at all.

Plus, it says not edit it manually...

Thanks

---

Sample package/R/function.R code

#' @export
#' @import data.table
test_data_table = function(dt) {
  dt[, a := 3]
}

---

Call example

> test_data_table
function(dt) {
  dt[, a := 3]
}
<environment: namespace:package>

> test_data_table(dt)
 Show Traceback

 Rerun with Debug
 Error in `[.data.frame`(x, i, j) : could not find function ":=" 

回答1:

You probably shouldn't use import(*) at all, unless you really need every exported object from a package. Instead, use importFrom(pkg, obj1, obj2, ...) to import only those objects you need.

From the Writing R Extensions manual, S1.5.1:

Using importFrom selectively rather than import is good practice and recommended notably when importing from packages with more than a dozen exports.

Nonetheless, if you do need to import everything, use #' @import data.table.

来源：https://stackoverflow.com/questions/40888820/r-added-importdata-table-to-namespace-automatically-using-devtools