Yes, if I just list data.table in Imports in my DESCRIPTION file, then I have to use :: every time I call functions that are outside the base package. The only workaround is using import data.table in the NAMESPACE.
On Tue, Jan 20, 2015, 10:41 Arunkumar Srinivasan <[email protected]> wrote: > There should be no need to use :: to call data.table functions then. You > can use all the exported functions as such. And `:=` within DT[...] would / > should work just fine.. > > Now that I understand your setup, why do you think you need to use :: for > every data.table function? What happens when you don't? And why did you get > error with :=? > > On Tue, Jan 20, 2015 at 2:36 PM, Juan Manuel Truppia <[email protected]> > wrote: > >> Myself as the developer trying to use data.table functions from within my >> package >> >> On Tue, Jan 20, 2015, 10:32 Arunkumar Srinivasan <[email protected]> >> wrote: >> >>> On Tue, Jan 20, 2015 at 2:22 PM, Juan Manuel Truppia < >>> [email protected]> wrote: >>> >>>> Let's follow an example. I'm developing my own package. I add >>>> data.table to imports in my description file. This means I have to use the >>>> :: operator each time I want to call a data.table function. Can I use := >>>> in this setup? >>>> >>> "I have to use / Can I use" - here you refer to the user using your >>> package or yourself as the developer trying to use data.table functions and >>> := from within your package? >>> >>> >>>> >>>> On Tue, Jan 20, 2015, 10:01 Arunkumar Srinivasan <[email protected]> >>>> wrote: >>>> >>>>> Juan, >>>>> >>>>>> >>>>>> I already know that. >>>>>> >>>>> Okay, great. >>>>> >>>>>> I usually struggle when using data.table inside my own packages. I >>>>>> start by listing it in imports only (and not importing anything) >>>>>> >>>>> "imports only (and not importing anything)"? - what do you mean? >>>>> >>>>>> but end up depending on it, as for the users to be able to manipulate >>>>>> the data.tables with [ and :=. >>>>>> >>>>> It depends on whether you want the data.table NAMESPACE to be attached >>>>> or not. I think these posts may help: >>>>> >>>>> http://r.789695.n4.nabble.com/Re-R-CMD-check-checking-in-development-version-of-R-td4696125.html#none >>>>> >>>>> http://stackoverflow.com/questions/8637993/better-explanation-of-when-to-use-imports-depends >>>>> >>>>> >>>>>> I end up importing some or all of data.table also, because I don't >>>>>> know how to call := the :: notation. >>>>>> >>>>> I don't really follow this. Why do you want to use `::` along with >>>>> `:=`. The last post we just discussed that it can't be done, as it is not >>>>> designed to be used outside of `[...]` and in very specific ways. Check >>>>> data.table:::`:=`. It is designed to error. This post might help: >>>>> http://stackoverflow.com/q/7033106/559784 >>>>> >>>>>> My specific problem was on using := during on.Load. >>>>>> >>>>> It'd be useful to know what you are trying to do, along with your >>>>> code. >>>>> >>>>>> I already know how to use it, and know that it can only be used >>>>>> inside [. >>>>>> Maybe it is imperative to @import data.table to be able to use :=? >>>>>> >>>>> I don't follow exactly how you are trying to use := to answer this. >>>>> >>>>> Arun >>>>> >>>>>> >>>>>> On Mon, Jan 19, 2015, 19:35 Arunkumar Srinivasan < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> Within the square brackets in "DT[ .... ]" and even there, only in >>>>>>> `j` (as the error message points out). >>>>>>> >>>>>>> On Mon, Jan 19, 2015 at 11:31 PM, Juan Manuel Truppia < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> Arun, what does "within the frame of data.table" mean? >>>>>>>> >>>>>>>> On Mon, Jan 19, 2015, 19:17 Arunkumar Srinivasan < >>>>>>>> [email protected]> wrote: >>>>>>>> >>>>>>>>> Juan, >>>>>>>>> >>>>>>>>> `:=` is designed to be used only within the frame of data.table. >>>>>>>>> >>>>>>>>> On Mon, Jan 19, 2015 at 10:45 PM, Juan Manuel Truppia < >>>>>>>>> [email protected]> wrote: >>>>>>>>> >>>>>>>>>> Hi, I'm using data.table inside my own packages. I'm having some >>>>>>>>>> trouble using data.table functions on my .onLoad method. >>>>>>>>>> I'm actually depending (not importing) data.table, but even then, >>>>>>>>>> I can't get := to work in .onLoad. >>>>>>>>>> I'm using the `:=`(a = x, b = y) version, and getting >>>>>>>>>> >>>>>>>>>> Error in `:=`(a = x) : >>>>>>>>>> Check that is.data.table(DT) == TRUE. Otherwise, := and `:=`(...) >>>>>>>>>> are defined for use in j, once only and in particular ways. See >>>>>>>>>> help(":="). >>>>>>>>>> >>>>>>>>>> If I comment that, and then run it from the console after the >>>>>>>>>> package is loaded, it works. >>>>>>>>>> >>>>>>>>>> Any ideas? >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> datatable-help mailing list >>>>>>>>>> [email protected] >>>>>>>>>> >>>>>>>>>> https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help >>>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>> >
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