[R] Reading in multiple files

[Liaw, Andy]

Try:

tmpf <- list.files("c:/temp")
dat <- read.csv(tmpf[1])
for (f in tmpf[-1]) {
    dat <- rbind(dat, read.csv(f)
}

If the data are all numeric, reading them as matrices could be a lot more
efficient.  Or you can specify the colclass argument to speed up read.csv().

Another way is to concatenate all the files into one (using things like
`cat') outside of R, and read it in at once.

HTH,
Andy


> -----Original Message-----
> From: Bliese, Paul D MAJ WRAIR-Wash DC
> [mailto:Paul.Bliese at na.amedd.army.mil]
> Sent: Wednesday, April 09, 2003 9:52 AM
> To: r-help at stat.math.ethz.ch
> Subject: [R] Reading in multiple files
> 
> 
> I apologize if this is a FAQ -- I kind of recall seeing 
> something along
> these lines before, but I couldn't find the message when I 
> searched the
> archives.
> 
> Problem:
> 1. I have hundreds of small files in a subdirectory 
> ("c:\\temp") and I would
> like to combine the files into a single data frame.
> 2. Individually, it is easy to read each file
> >DATA<-read.csv("c:\\temp\\file1a.csv",header=T)
> 3. It is also fairly easy to add new files to the data frame 
> one at a time:
> >DATA<-rbind(DATA,read.csv("c:\\temp\\file1b.csv",header=T))
> 
> What is tedious about this solution is that we have to change 
> the file name
> in step 3 every time.
> 
> Is there a way to have R identify all the files in a 
> directory and create
> one big data frame?
> 
> I'm working in Windows with R 1.6.2.
> 
> Thanks
> 
> Paul
> MAJ Paul Bliese, Ph.D.
> Walter Reed Army Institute of Research
> Phone: (301) 319-9873
> Fax: (301) 319-9484
> paul.bliese at na.amedd.army.mil
> 
> ______________________________________________
> R-help at stat.math.ethz.ch mailing list
> https://www.stat.math.ethz.ch/mailman/listinfo/r-help
> 

------------------------------------------------------------------------------