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rdata.tableroxygen2

How to import data.table indexing functionality?

What is the proper way to import the data.table indexing functionality A[ , , by = ...] into my package?

Should I have my roxygen docs contain:

importFrom data.table [.data.table

Solution

  • Looks like you need to import just data.table function and [ method will be correctly dispatched.

    subdt/R/mysubdt.R

    mysubdt = function(x) {
    stopifnot(class(x)[1L]=="data.table", c("s","g","v") %in% names(x), is.logical(x[["s"]]))
    x[s==TRUE, sum(v), by=g]
}

    subdt/NAMESPACE

    importFrom(data.table, data.table)
export(mysubdt)

    After build and install package (you don't need :: if you load data.table too, code assumes you didn't):

    library(subdt)
x = data.table::data.table(
    s = c(TRUE,TRUE,FALSE,TRUE),
    g = c("a","b","a","b"),
    v = 1:4/10
)
mysubdt(x)
#   g  V1
#1: a 0.1
#2: b 0.6