Sorry, got cut off... On Thu, Jul 26, 2012 at 8:07 AM, Bert Gunter <bgun...@gene.com> wrote: > 1. m2q already is a data frame, so the m2qldf statement that follows > is completely unnecessary. > > 2. Please read ?read.table carefully, and especially the bit about the > stringsAsFactors argument. The problem is that by default character > strings are read in as factors, not characters strings. So you can > either change the way they are read in thru stringsAsFactors=FALSE or > otherwise as explained therein -- or convert them with as.character() > when you access them, e.g.
x1<-read.csv(file=as.character(m2q[1,2])) -- Bert > > On Thu, Jul 26, 2012 at 7:53 AM, jpm miao <miao...@gmail.com> wrote: >> Dear All, >> >> >> >> I would like to read the data file via read.csv (the 3rd line of the >> following program) and the file name is stored in a dataframe. Since I have >> several files to read, I store the file names as well as the sample period >> inside a file “B_M2Q.csv” and I read the file name first, and then read the >> data file. >> >> >> >> The content of the file "B_M2Q.csv" is >> >> FX >> >> "A_FX_M.csv" >> >> "1981-01" >> >> "2012-06" >> >> Int >> >> "A_Int.csv" >> >> "1970-01" >> >> "2012-03" >> >> (The file is attached to this email) >> >> >> The three-line program is as follows: >> >> >> m2q<-read.csv(file="B_M2Q.csv", header=FALSE) # Read the file containing >> file names and sampling periods of numerical data >> >> m2qdf<-as.data.frame(m2q) #Make the file of filenames a dataframe >> # Read the numerical data >> >> Nevertheless, there is an error when I attempt to read the numerical data >> >> >> >>> x1<-read.csv(file=m2qdf[1,2]) >> >> Error in read.table(file = file, header = header, sep = sep, quote = quote, >> : >> >> 'file' must be a character string or connection >> >> It is a problem of the file name , since I can read the data smoothly if I >> change the line to >> >>> x1<-read.csv(file="A_FX_M.csv") >> >> Could someone tell me what the problem is? >> How can modify the orignal program so that I can store the sampling periods >> and filenames in a dataframe, and then I read it? >> How can I correctly access a string element of a dataframe? >> >> Thanks, >> >> Miao >> >> ______________________________________________ >> 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. >> > > > > -- > > Bert Gunter > Genentech Nonclinical Biostatistics > > Internal Contact Info: > Phone: 467-7374 > Website: > http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm -- Bert Gunter Genentech Nonclinical Biostatistics Internal Contact Info: Phone: 467-7374 Website: http://pharmadevelopment.roche.com/index/pdb/pdb-functional-groups/pdb-biostatistics/pdb-ncb-home.htm ______________________________________________ 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.