import all the functions of a package except one when building a package

Question

I'm building an R package (mypackage) that imports data.table and another package (let's call it myotherpackage).

Imports: data.table, myotherpackage is in the DESCRIPTION file of mypackage.

myotherpackage imports dplyr, which has several functions named like the data.table functions, so I get warnings like this everytime I load mypackage:

Warning: replacing previous import ‘data.table::first’ by ‘dplyr::first’ when loading ‘mypackage’

Is there a way to import all the functions of data.table except "first" for example? I'd then use data.table::first in the code if I need to use it. Or is there a better way to handle it? I'm trying to avoid the warning every time someones imports the package. Thank you!

Use importFrom(my other package, function) directives in your NAMESPACE rather than importing all functions from the package. — Thomas
Thanks @Thomas. I was hoping that there would be an alternative to specifying every data.table function I want to import (which is pretty much all of them). Looks like I'm out of luck. — Julien Massardier
You can also specify import(data.table, except=c(foo)). See cran.r-project.org/doc/manuals/r-devel/…. I don't know if you can get that using roxygen markup, though. — Thomas
Yes! @Thomas, it worked! I had to use the following syntax in the function description (instead of #' @import data.table): #' @rawNamespace import(data.table, except = first) Do you wanna answer the question so I can give you credit? — Julien Massardier

Thomas Thomas · Accepted Answer · 2018-08-18T22:39:19

The NAMESPACE file is somewhat flexible here, as described in Writing R Extensions.

The two main import directives are:

import(PACKAGE)

which imports all objects in the namespace into your package. The second option is to do specific imports using:

importFrom(PACKAGE, foo)

which gives you access to foo() without needing the fully qualified reference PACKAGE::foo().

But these aren't the only two options. You can also use the except argument to exclude just a handful of imports:

import(PACKAGE, except=c(foo,bar))

which gives you everything from PACKAGE's namespace but foo() and bar(). This is useful - as in your case - for avoiding conflicts.

For roxygen, great catch on figuring out that you can do:

#' @rawNamespace import(PACKAGE, except = foo)

to pass a raw NAMESPACE directive through roxygen.

import all the functions of a package except one when building a package

1 Answers