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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