Okay I appreciate the help, and I appreciate the FAQ reminder. I will read the r-help posting guide. I'm relatively new to using the support systems around R. So far everyone has been really helpful.
I'm confused as to which data.table "list" I should be using. http://lists.r-forge.r-project.org/pipermail/datatable-commits/ doesn't appear to be correct. Or just directly sending an email to all of you? Thanks again, Rob On Wed, Mar 3, 2010 at 6:05 AM, Matthew Dowle <mdo...@mdowle.plus.com>wrote: > > I'd go a bit further and remind that the r-help posting guide is clear : > > " For questions about functions in standard packages distributed with R > (see the FAQ Add-on packages in R), ask questions on R-help. > If the question relates to a contributed package , e.g., one downloaded > from > CRAN, try contacting the package maintainer first. You can also use > find("functionname") and packageDescription("packagename") to find this > information. ONLY send such questions to R-help or R-devel if you get no > reply or need further assistance. This applies to both requests for help > and > to bug reports. " > > The "ONLY" is in bold in the posting guide. I changed the bold to capitals > above for people reading this in text only. > > Since Tom and I are friendly and responsive, users of data.table don't > usually make it to r-help. We'll follow up this one off-list. Please note > that Rob's question is very good by the rest of the posting guide, so no > complaints there, only that it was sent to the wrong place. Please keep > the > questions coming, but send them to us, not r-help. > > You do sometimes see messages to r-help starting something like "I have > contacted the authors/maintainers but didn't hear back, does anyone know > ...". To not state that they had would be an implicit request for further > work by the community (for free) to ask if they had. So its not enough to > contact the maintainer first, but you also have to say that you have as > well, and perhaps how long ago too would be helpful. For r-forge projects > I > usually send any question to everyone on the project (easy to find) or if > they have a list then to that. > > HTH > Matthew > > > "Tom Short" <tshort.rli...@gmail.com> wrote in message > news:fd27013a1003021718w409acb32r1281dfeca5593...@mail.gmail.com... > On Tue, Mar 2, 2010 at 7:09 PM, Rob Forler <rfor...@uchicago.edu> wrote: > > Hi everyone, > > > > I have the following code that works in data frames taht I would like tow > > ork in data.tables . However, I'm not really sure how to go about it. > > > > I basically have the following > > > > names = c("data1", "data2") > > frame = data.frame(list(key1=as.integer(c(1,2,3,4,5,6)), > > key2=as.integer(c(1,2,3,2,5,6)),data1 = c(3,3,2,3,5,2), data2= > > c(3,3,2,3,5,2))) > > > > for(i in 1:length(names)){ > > frame[, paste(names[i], "flag")] = frame[,names[i]] < 3 > > > > } > > > > Now I try with data.table code: > > names = c("data1", "data2") > > frame = data.table(list(key1=as.integer(c(1,2,3,4,5,6)), > > key2=as.integer(c(1,2,3,2,5,6)),data1 = c(3,3,2,3,5,2), data2= > > c(3,3,2,3,5,2))) > > > > for(i in 1:length(names)){ > > frame[, paste(names[i], "flag"), with=F] = as.matrix(frame[,names[i], > > with=F] )< 3 > > > > } > > Rob, this type of question is better for the package maintainer(s) > directly rather than R-help. That said, one answer is to use list > addressing: > > for(i in 1:length(names)){ > frame[[paste(names[i], "flag")]] = frame[[names[i]]] < 3 > } > > Another option is to manipulate frame as a data frame and convert to > data.table when you need that functionality (conversion is quick). > > In the data table version, frame[,names[i], with=F] is the same as > frame[,names[i], drop=FALSE] (the answer is a list, not a vector). > Normally, it's easier to use [[]] or $ indexing to get this. Also, > fname[i,j] <- something assignment is still a bit buggy for > data.tables. > > - Tom > > Tom Short > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
