You appear to have a good start. If you type alldata[[1]] do you get what you expect for the first file?
This is not tested, but I would start with something like this: sorteddata <- lapply(alldata, function(df) df[order(df$Name),] ) ## then this will overwrite for (id in seq(filenames)) { write.csv( sorteddata[[id]] , filenames[id] ) } ## or changed something like this for new files write.csv( sorteddata[[id]] , paste('sorted_',filenames[id],sep='') ) An you'll want to check the other arguments to write.csv(), or possibly use write.table(). For learning purposes: tmp <- alldata[[1]] tmp[order(tmp$Name),] ## to sort by Name tmp[order(tmp[,2]),] ## to sort by 2nd column -- Don MacQueen Lawrence Livermore National Laboratory 7000 East Ave., L-627 Livermore, CA 94550 925-423-1062 On 5/18/12 9:56 AM, "Matthew Ouellette" <mouellett...@gmail.com> wrote: >Dear R help list, > >I am very new to R and I apologize in advance if this has been answered >before. I have done my best to google/R search what I need but no luck. > Here is what I am attempting: > >I have hundreds of .csv files that I need to sort based on a single column >of alphanumeric data. All of the files contain matrices that have >identical dimensions and headers, however the data table doesn't begin >until the 74th line in each file. Doing some searching, I have been able >to create an object with elements consisting of each file in the folder >containing the targets (please note this is my working directory): > >filenames<-list.files() >alldata<-lapply(filenames, read.csv, skip=73, header=TRUE) > >At this point I believe I have created an object with N elements (where >N=# >files in the wd), each containing the matrix I am attempting to sort. I >am >completely lost as to how I can sort each matrix based on a single column >(say, "Name") and then either overwrite the source files or write to a new >directory all of the sorted data. I half wonder if I should be creating >individual objects for each file that I read in, but I haven't been able >to >figure this out either. Please note that I am trying to sort these files >individually - would a loop be more efficient? > >I appreciate the help, >BustedAvi > > [[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.