R help - Jan 2013 - importing data

Dear All,

Sorry for asking a newbie question. I want to ask how to import 1000
datasets whose file names are labelled from data1.dat to data1000.dat into
R so that they are named M[1, , ] to M[1000, , ] accordingly. Thank you
very much.

Best Regards,
Ray

	[[alternative HTML version deleted]]

On Wed, Jan 23, 2013 at 9:16 AM, Ray Cheung <ray1728 at gmail.com>
wrote:
> Dear All,
>
> Sorry for asking a newbie question. I want to ask how to import 1000
> datasets whose file names are labelled from data1.dat to data1000.dat into
> R so that they are named M[1, , ] to M[1000, , ] accordingly. Thank you
> very much.
>,
Hi Ray,

I'm pretty sure you don't mean "named" M[1,,] etc. but rather
that
there's only one object M and that's how the slices come into
existence:

What you'll want to do is something like this:

little_helpful_function(n){
    file_name <- paste("data", n, ".dat", sep =
"")
    read.dta(file_name, ##OTHER PARAMETERS)
}

list_of_datasets <- lapply(1:1000, little_helpful_function)

output <- do.call(c, list_of_datasets)

dim(output) <- c(dim(list_of_datasets[[1]]), 1000)

Or something like that. Note that I'm not quite sure what a dta file
is, so I'll leave it to you to find an appropriate read.dta function.

Feel free to write back (cc'ing the list) if you don't understand all
of the above.

Cheers,
Michael
> Best Regards,
> Ray
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at 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.

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
Université de Bourgogne
UMR CNRS/uB 6282 Biogéosciences
6 Boulevard Gabriel
21000 Dijon, FRANCE
+33(0)3.80.39.63.06
ivan.calandra@u-bourgogne.fr
http://biogeosciences.u-bourgogne.fr/calandra

Le 26/01/13 10:03, Ray Cheung a écrit :
> 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@u-bourgogne.fr
<mailto:ivan.calandra@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
>     Université de Bourgogne
>     UMR CNRS/uB 6282 Biogéosciences
>     6 Boulevard Gabriel
>     21000 Dijon, FRANCE
>     +33(0)3.80.39.63.06 <tel:%2B33%280%293.80.39.63.06>
>     ivan.calandra@u-bourgogne.fr
<mailto:ivan.calandra@u-bourgogne.fr>
>     http://biogeosciences.u-bourgogne.fr/calandra
>
>     Le 25/01/13 10:00, R. Michael Weylandt a écrit :
>
>         On Fri, Jan 25, 2013 at 6:11 AM, Ray Cheung <ray1728@gmail.com
>         <mailto:ray1728@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
>
>         ______________________________________________
>         R-help@r-project.org <mailto: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 <mailto: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.
>
>
	[[alternative HTML version deleted]]