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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