importing data

Thanks a million for all help provided!! I can do what I intend to 
using the "for loop". However, I'm still eager to try the list.files 
approach. Here is the error message that I got using Ivan's code:

list_of_dataset <- do.call(read.table, file_names)

Error in do.call(read.table, file_names) : second argument must be a list

Please advise.

Ray

On Sun, Jan 27, 2013 at 10:57 PM, Ivan Calandra 
<ivan.calandra at u-bourgogne.fr <mailto:ivan.calandra at u-bourgogne.fr>> 
wrote:

    Hi Ray!

    I'm insisting with list.files...!

    What about like this (untested)?
    file_names <- list.files(path="C:/.../data", pattern=".dat$",
    full.names=TRUE)
    list_of_dataset <- do.call(read.table, file_names)

    Let me know if this helps!
    Ivan

    -- Ivan CALANDRA Universit? de Bourgogne UMR CNRS/uB 6282
    Biog?osciences 6 Boulevard Gabriel 21000 Dijon, FRANCE
    +33(0)3.80.39.63.06 <tel:%2B33%280%293.80.39.63.06>
    ivan.calandra at u-bourgogne.fr <mailto:ivan.calandra at u-bourgogne.fr>
    http://biogeosciences.u-bourgogne.fr/calandra

    Le 26/01/13 10:03, Ray Cheung a ?crit :

    Thanks for your commands, Ivan and Michael! However, I am still
    not producing the right codes. Would you please help me on
    this? I've written the following codes. Please comment. Thank you
    very much.
    Task: Reading data1.dat to data1000.dat (with missing files) into
    R. Missing files can be omitted in the list.
    ###FUNCTION TO READ FILES
    little_helpful <- function(n) {
    file_name <- paste0("C:/.../data", n, ".dat")
    read.table(file_name)
    }
    ###RETURN AN OBJECT WHICH CHECKS FOR THE EXISTENCE OF FILES
    check  <- function(n) {
    a <- ifelse(file.exists(paste0("C:/.../data", n, ".dat")), 1, 0)
    a
    }
    ###Combining the functions
    IMPORT <- function(n) {
       L <- check(1:n)
       for (i in 1:n) {
          if (L[i] == 1)
          list_of_datasets <- lapply(i, little_helpful) else
    list_of_datasets <- 0
          }
       list_of_datasets
       }
    Thanks for all comments.
    Best Regards,
    Ray

    On Fri, Jan 25, 2013 at 5:48 PM, Ivan Calandra
    <ivan.calandra at u-bourgogne.fr
    <mailto:ivan.calandra at u-bourgogne.fr>> wrote:

        Hi,

        Not sure this is what you need, but what about list.files()?
        It can get you all the files from a given folder, and you
        could then work this list with regular expressions for example.

        HTH,
        Ivan

        --
        Ivan CALANDRA
        Universit? de Bourgogne
        UMR CNRS/uB 6282 Biog?osciences
        6 Boulevard Gabriel
        21000 Dijon, FRANCE
        +33(0)3.80.39.63.06 <tel:%2B33%280%293.80.39.63.06>
        ivan.calandra at u-bourgogne.fr
        <mailto:ivan.calandra at u-bourgogne.fr>
        http://biogeosciences.u-bourgogne.fr/calandra

        Le 25/01/13 10:00, R. Michael Weylandt a ?crit :

            On Fri, Jan 25, 2013 at 6:11 AM, Ray Cheung
            <ray1728 at gmail.com <mailto:ray1728 at gmail.com>> wrote:

                Dear Michael,

                Thanks for your codes. However, lapply does not work
                in my case since I've
                some files missing in the data (say, the file
                data101.dat). Do you have any
                suggestions on this?? Thank you very much.

            You could simply add a test using file.exists() but I'm
            not sure what
            you want to do with the M matrix then -- omit the slice
            (so the others
            are all shifted down one) or fill it entirely with NA's.

            Michael