[R] "global parameter" warning using data.table in package.

[Bert Gunter]

I believe these questions belong on r-package-devel, not here.

Bert Gunter

"The trouble with having an open mind is that people keep coming along and
sticking things into it."
-- Opus (aka Berkeley Breathed in his "Bloom County" comic strip )


On Fri, Mar 5, 2021 at 5:25 AM Martin Møller Skarbiniks Pedersen <
traxplayer using gmail.com> wrote:

> Hi,
>
>   I am converting a couple of functions into a R-package. Many of the
> functions use data.table.
>   I have two questions using data.table in my own package.
>   Normally I would put each question in separate emails but I think they
> might be connected.
>
> First question is short and I think the answer is yes.
> 1. Do I always need to prefix data.table each time I use something from
> that package?
> Eg. DT <- data.table::data.table(x=rep(c("b","a","c"),each=3), y=c(1,3,6),
> v=1:9)
>
> Second question is longer.
> 2.  In this small example code:
> hello <- function() {
>   DT <- data.table::data.table(x=rep(c("b","a","c"),each=3), y=c(1,3,6),
> v=1:9)
>   DT[, .(sum(v))]
> }
>
> I get these warnings from R CMD check:
> hello: no visible global function definition for ‘.’
> hello: no visible binding for global variable ‘v’
> Undefined global functions or variables:
>   . v
>
> According to: vignette("datatable-importing", package = "data.table")
> The solution is
> hello <- function() {
>   v <- NULL
>   . <- NULL
>
> And it works but looks a bit weird.
> Is there a better solution?
>
> Regards
> Martin
>
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>
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