[R] Reading multiple txt files into one data frame

[Paul Lemmens]

On 7/30/06, Kartik Pappu <kartik.pappu at gmail.com> wrote:
> Hello All,
>
> I have a device that spews out experimental data as a series of text
> files each of which contains one column with several rows of numeric
> data.  My problem is that for each trial it gives me one text file
> (and I run between 30 to 50 trials at a time) and I would ideally like
> to merge all these text files into one large data frame with each
> column representing a single trial.  It is not a problem if NA
> characters are added to make all the columna of eaqual length.  Right
> now I am doing this by opening each file individually and cutting and
> pasting the data into an excel file.  How can I do this in R assuming
> all my text files are in one directory.
>
> Is it also possible to customize the column headers.  For example if I
> have 32 trials and 16 are experimental and 16 are control and I want
> to name the columns "Expt1", Expt2",... "Expt16"  and the control
> columns "Cntl1",...Cntl16".
>
> Kartik
>
setwd("E:/Cooperation @ Delft-Nijmegen (Feb. 2006 - Sep.
2006)/Research/Study 20 - Roughness/Experiment 20a - Roughness Index
for CUReT textures/Statistics")

#  Concatenate the raw data files.
data.path = "../data files/"
(datafiles <- list.files(path=data.path, pattern="subject\_[0-9]+\.txt$"))
exp20a <- do.call('rbind',
  lapply(datafiles,
    function(x) read.table(paste(data.path, x, sep=""))))
rm(datafiles, data.path)