HI, "Find 'T','C','A','F' and 'Y', delete them from all the 110 files" I assume that you meant to replace it with NA.
set.seed(28) myfiles<- lapply(1:5,function(i) as.data.frame(matrix(sample(c(LETTERS,"-999.99M"),40*i,replace=TRUE),ncol=(40*i)/8),stringsAsFactors=FALSE)) myfiles[[1]] # V1 V2 V3 V4 V5 #1 A P K O Y #2 C Z S M Y #3 M S -999.99M G I #4 X R M G X #5 C Q G A P #6 U W G B K #7 A N Z X R #8 X I F M K res<-lapply(myfiles,function(x) {x1<-unlist(x); x1[x1%in% c("-999.99M","T","C","A","F","Y")]<-NA;as.data.frame(matrix(x1,ncol=ncol(x)),stringsAsFactors=FALSE)}) res[[1]] # V1 V2 V3 V4 V5 #1 <NA> P K O <NA> #2 <NA> Z S M <NA> #3 M S <NA> G I #4 X R M G X #5 <NA> Q G <NA> P #6 U W G B K #7 <NA> N Z X R #8 X I <NA> M K lapply(seq_along(res),function(i) write.table(res[[i]],paste0("file",i,".txt"),row.names=FALSE,quote=FALSE)) A.K. ----- Original Message ----- From: Zilefac Elvis <zilefacel...@yahoo.com> To: "r-help@r-project.org" <r-help@r-project.org> Cc: Sent: Saturday, April 27, 2013 11:20 AM Subject: [R] Help Hello, I have a question and need your help urgently. I am new to R but want to learn it. I have several files in a folder which I have imported to R using : temp = list.files(pattern="*.txt") >myfiles = lapply(temp, read.delim) The resulting files are on the workspace stored as List[110]. So they are 110 files in the list. Each file has several different columns and rows. My question: I would like to find and replace -999.99M with NA; Find 'T','C','A','F' and 'Y', delete them from all the 110 files. Then, I want to write.table all the corrected files back to a folder on my computer. Thanks for your help. Atem. ________________________________ From: "r-help-requ...@r-project.org" <r-help-requ...@r-project.org> Sent: Friday, April 26, 2013 11:08 AM Subject: confirm bfdc3137cee0135cf3c616295c9d0e2b3adfd392 Mailing list subscription confirmation notice for mailing list R-help We have received a request from 129.132.148.130 for subscription of r-help@r-project.org mailing list. To confirm that you want to be added to this mailing list, simply reply to this message, keeping the Subject: header intact. Or visit this web page: https://stat.ethz.ch/mailman/confirm/r-help/bfdc3137cee0135cf3c616295c9d0e2b3adfd392 Or include the following line -- and only the following line -- in a message to r-help-requ...@r-project.org: confirm bfdc3137cee0135cf3c616295c9d0e2b3adfd392 Note that simply sending a `reply' to this message should work from most mail readers, since that usually leaves the Subject: line in the right form (additional "Re:" text in the Subject: is okay). If you do not wish to be subscribed to this list, please simply disregard this message. If you think you are being maliciously subscribed to the list, or have any other questions, send them to r-help-ow...@r-project.org. [[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.