问题
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!
回答1:
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.
来源：https://stackoverflow.com/questions/51899220/import-all-the-functions-of-a-package-except-one-when-building-a-package