use is.null for the test if (is.null(indexSkipped))
Sent from my iPad On May 22, 2012, at 2:10, Alaios <ala...@yahoo.com> wrote: > Dear all, > I have a code that looks like the following (I am sorry that this is not a > reproducible example) > > > indexSkipped<-NULL > > > > ....code Skipped that might alter indexSkipped > > > if (length(indexSkipped)==0) > > spatial_structure<-spatial_structures_from_measurements(DataList[[i]]$Lon,DataList[[i]]$Lat,meanVector) > > else > > spatial_structure<-spatial_structures_from_measurements(DataList[[i]]$Lon[-indexSkipped],DataList[[i]]$Lat[-indexSkipped],meanVector) > # > > > > What I am doing here is that I am processing files. Every files has a > measurement table and Longtitude and Latitude fields. If one file is marked > as invalid I keep a number of of the skipped index so to remove the element > of the Longtitude and Latitide vectors. > > 1) That works correct, I was just wondering if it would be possible to remove > some how the given if statement and initialize the indexSkipped in such a way > so > > the DataList[[i]]$Lon[-indexSkipped],DataList[[i]]$Lat[-indexSkipped] do > nothing, aka remove no element, in case the indexSkipped remains unchanged > (in its initial value). > > 2) When u define a variable as empty, I usually use NULL, how I can check > afterwords if that holds or not. If I use the > > (indexSkipped==NULL) > logical(0) > > this does not return true or false. How I can do that check? > > > Iwould like to thank you in advance for your help > > B.R > Alex > [[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. ______________________________________________ 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.
