Hi see in line
> -----Original Message----- > From: R-help [mailto:r-help-boun...@r-project.org] On Behalf Of Martin > Moller Skarbiniks Pedersen > Sent: Friday, September 8, 2017 11:58 AM > To: r-help@r-project.org > Subject: Re: [R] Optimize code to read text-file with digits > > On 8 September 2017 at 11:25, PIKAL Petr <petr.pi...@precheza.cz> wrote: > > > > Moller Skarbiniks Pedersen > > > My program which is slow looks like this: > > > > > > filename <- "digits.txt" > > > lines <- readLines(filename) > > > > why you do not read a file as a whole e.g. by > > > > lines<-read.table("digits.txt") > > > > Good idea. > > > > > And now I am lost. > > > [...] > > > > Or do you want one big numeric vector from all your numbers? > > here you need to read values as character variables > > > > Yes. That's what I am looking for. ********************* Well, this is how you cen get your numeric vector of length 1e6 set.seed(111) numbers0<-sample(0:9, 1e6, replace=TRUE) If you want to get this number vector from the file it is better to use lists and lapply but maybe with loop it can be done too First I prepare some data> daf<-as.character(numbers0) index<- 0:(1e6-1) index<-index%/%5 lll<-split(daf, index) lll<-lapply(lll, paste, collapse="") daf<-do.call(rbind, lll) dim(daf)<-c(20000,10) daf<-as.data.frame(daf) # here we have data frame similar to what you can get with read.table head(daf) V1 V2 V3 V4 V5 V6 V7 V8 V9 V10 1 57353 75381 66866 52351 03707 13763 76897 67383 02972 37636 2 40540 52811 02521 18199 23236 64967 70123 46962 95347 47379 3 55001 55094 36922 08811 77704 99060 65902 28279 29131 98979 4 41936 77976 71345 84996 36865 11825 11024 90616 35653 10772 5 42339 89821 23790 62176 03266 36054 34882 06822 10087 05317 6 36275 45199 80796 54458 38836 87953 64394 02685 25788 19502 > # now it is time transform data.frame to numeric vector # Change to list, transform to character, split to items, unlist and make numeric lll<- as.list(daf) lll<-lapply(lll, as.character) numbers<-lapply(lll, strsplit,"") numbers <- as.numeric(unlist(numbers)) length(numbers) [1] 1000000 > all.equal(numbers, numbers0) [1] TRUE > all this is computed in less than 1 second, is it really so slow? Cheers Petr ****************** > > > > > lines<-read.table("digits.txt", colClasses="character") > > numbers<-as.numeric(unlist(strsplit(as.character(lines[1,]),""))) > > changes first row to numeric vector. > > > > > Do I still need to loop through all lines? > It is maybe even slower now. > > numbers <- vector('numeric') > for (i in 1:nrows(lines)) { > numbers <- c(numbers, as.numeric(unlist(strsplit(as. > character(lines[i,]),"")))) > } > > > > Anyway, can you explain what is your final goal? > > > > > A numeric vector of length 1 million. Each element should be one digit. > > > > Cheers > > Petr > > > > > Thanks. > /Martin > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. ________________________________ Tento e-mail a jakékoliv k němu připojené dokumenty jsou důvěrné a jsou určeny pouze jeho adresátům. Jestliže jste obdržel(a) tento e-mail omylem, informujte laskavě neprodleně jeho odesílatele. Obsah tohoto emailu i s přílohami a jeho kopie vymažte ze svého systému. Nejste-li zamýšleným adresátem tohoto emailu, nejste oprávněni tento email jakkoliv užívat, rozšiřovat, kopírovat či zveřejňovat. Odesílatel e-mailu neodpovídá za eventuální škodu způsobenou modifikacemi či zpožděním přenosu e-mailu. 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