D'oh! Completely missed that. Definately a case or RTFMS (RTFM, Stupid). My apologies for the spam.
Sincerely (with additional grovelling) Cormac. On 23 June 2011 15:59, Nick Sabbe <nick.sa...@ugent.be> wrote: > Hello Cormac. > > Not having thoroughly checked whether your code actually works, the behavior > of rle you describe is the one documented (check the details of ?rle) and > makes sense as the missingness could have different reasons. > As such, changing this type of behavior would probably break a lot of > existing code that is built on top of rle. > > There are other peculiarities and disputabilities about some base R > functions (the order of the arguments for sample trips me every time), but > unless the argument is really strong or a downright bug, I doubt people will > be willing to change this. Perhaps making the new behavior optional (through > a new parameter na.action or similar, with the default the original > behavior) is an option? > > Feel free to run your own version of rle in any case. I suggest you rename > it, though, as it may cause problems for some packages. > > > Nick Sabbe > -- > ping: nick.sa...@ugent.be > link: http://biomath.ugent.be > wink: A1.056, Coupure Links 653, 9000 Gent > ring: 09/264.59.36 > > -- Do Not Disapprove > > > > >> -----Original Message----- >> From: r-help-boun...@r-project.org [mailto:r-help-bounces@r- >> project.org] On Behalf Of Cormac Long >> Sent: donderdag 23 juni 2011 15:44 >> To: r-help@r-project.org >> Subject: [R] problem (and solution) to rle on vector with NA values >> >> Hello there R-help, >> >> I'm not sure if this should be posted here - so apologies if this is >> the case. >> I've found a problem while using rle and am proposing a solution to the >> issue. >> >> Description: >> I ran into a niggle with rle today when working with vectors with NA >> values >> (using R 2.31.0 on Windows 7 x64). It transpires that a run of NA >> values >> is not encoded in the same way as a run of other values. See the >> following >> example as an illustration: >> >> Example: >> The example >> rv<-c(1,1,NA,NA,3,3,3);rle(rv) >> Returns >> Run Length Encoding >> lengths: int [1:4] 2 1 1 3 >> values : num [1:4] 1 NA NA 3 >> not >> Run Length Encoding >> lengths: int [1:3] 2 2 3 >> values : num [1:3] 1 NA 3 >> as I expected. This caused my code to fail later (unsurprising). >> >> Analysis: >> The problem stems from the test >> y <- x[-1L] != x[-n] >> in line 7 of the rle function body. In this test, NA values return >> logical NA >> values, not TRUE/FALSE (again, unsurprising). >> >> Resolution: >> I modified the rle function code as included below. As far as I tested, >> this >> modification appears safe. The convoluted construction of naMaskVal >> should guarantee that the NA masking value is always different from >> any value in the vector and should be safe regardless of the input >> vector >> form (a raw vector is not handled since the NA values do not apply >> here). >> >> rle<-function (x) >> { >> if (!is.vector(x) && !is.list(x)) >> stop("'x' must be an atomic vector") >> n <- length(x) >> if (n == 0L) >> return(structure(list(lengths = integer(), values = x), >> class = "rle")) >> >> #### BEGIN NEW SECTION PART 1 #### >> naRepFlag<-F >> if(any(is.na(x))){ >> naRepFlag<-T >> IS_LOGIC<-ifelse(typeof(x)=="logical",T,F) >> >> if(typeof(x)=="logical"){ >> x<-as.integer(x) >> naMaskVal<-2 >> }else if(typeof(x)=="character"){ >> naMaskVal<- >> paste(sample(c(letters,LETTERS,0:9),32,replace=T),collapse="") >> }else{ >> naMaskVal<-max(0,abs(x[!is.infinite(x)]),na.rm=T)+1 >> } >> >> x[which(is.na(x))]<-naMaskVal >> } >> #### END NEW SECTION PART 1 #### >> >> y <- x[-1L] != x[-n] >> i <- c(which(y), n) >> >> #### BEGIN NEW SECTION PART 2 #### >> if(naRepFlag) >> x[which(x==naMaskVal)]<-NA >> >> if(IS_LOGIC) >> x<-as.logical(x) >> #### END NEW SECTION PART 2 #### >> >> structure(list(lengths = diff(c(0L, i)), values = x[i]), >> class = "rle") >> } >> >> Conclusion: >> I think that the proposed code modification is an improvement on the >> existing >> implementation of rle. Is it impertinent to suggest this R-modification >> to the >> gurus at R? >> >> Best wishes (in flame-war trepidation), >> Dr. Cormac Long. >> >> ______________________________________________ >> 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.
