Thanks Gabor, I have two questions: 1- Is there any difference between your code and the following one, with regards to Fld2 ?
### test ### Input <- "Fld1 Fld2 10 A 20 B 30 C 40 A " DF <- read.table(textConnection(Input), header = TRUE) DF$Fld2<-factor(DF$Fld2,levels= c("C", "A", "B"))) 2- do you see any way to bring flexibility to your method ? Because, it looks to me as, at this stage, I have to i) know the order of my levels before I read the table and ii) create one class per factor. My problem is that I am not really working on a specific dataset. My goal is to develop R scripts capable of handling datasets which have various contents but close structures. So, I really need to minimize the quantity of "user-specific" code. Sebastien Gabor Grothendieck a écrit : > You can create your own class and pass that to read table. In > the example below Fld2 is read in with factor levels C, A, B > in that order. > > > library(methods) > setClass("my.levels") > setAs("character", "my.levels", > function(from) factor(from, levels = c("C", "A", "B"))) > > > ### test ### > > Input <- "Fld1 Fld2 > 10 A > 20 B > 30 C > 40 A > " > DF <- read.table(textConnection(Input), header = TRUE, > colClasses = c("numeric", "my.levels")) > str(DF) > # or > DF <- read.table(textConnection(Input), header = TRUE, > colClasses = list(Fld2 = "my.levels")) > str(DF) > > > On 8/28/07, Sébastien <[EMAIL PROTECTED]> wrote: > >> Dear R-users, >> >> I have found this not-so-recent post in the archives - >> http://tolstoy.newcastle.edu.au/R/devel/00a/0291.html - while I was >> looking for a particular way to reorder factor levels. The question >> addressed by the author was to know if the read.table function could be >> modified to order the levels of newly created factors "according to the >> order that they appear in the data file". Exactly what I am looking for. >> As there was no reply to this post, I wonder if any move have been made >> towards the implementation of this suggestion. A quick look at >> ?read.table tells me that if this option was implemented, it was not in >> the read.table function... >> >> Sebastien >> >> PS: I am sorry to post so many messages on the list, but I am learning R >> (basically by trials & errors ;-) ) and no one around me has even a >> slight notion about it... >> >> ______________________________________________ >> R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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.