R help - Dec 2004 - read.table from a list of filenames

I am wondering if it is possible to read.table repeatedly from a list 
of file names into a new list of table names.

For example:

filenames <- list.files()

then with a function like

rf <- function(i) {
word??(filename[i]) <- read.table(filenames[i]) }

I can't seem to find a function like word?? that will be the object of 
another operation.   If this worked, then I could repeat it for the 
length of filenames.

Also, even the following function seems to give me an error, but I 
don't yet know why.

rf <- function(nam, i) {  nam <- read.table(filenames[i]) }


Any help would be very much appreciated.

Thanks,
Thomas
	[[alternative text/enriched version deleted]]

The solution is in section 7.21 of the R FAQ.  BTW, `rf' is a built-in R
function for generating random numbers from an F distribution, so better use
some other name.

Andy
> From: thomas hills
> 
> I am wondering if it is possible to read.table repeatedly from a list 
> of file names into a new list of table names.
> 
> For example:
> 
> filenames <- list.files()
> 
> then with a function like
> 
> rf <- function(i) {
> word??(filename[i]) <- read.table(filenames[i]) }
> 
> I can't seem to find a function like word?? that will be the 
> object of 
> another operation.   If this worked, then I could repeat it for the 
> length of filenames.
> 
> Also, even the following function seems to give me an error, but I 
> don't yet know why.
> 
> rf <- function(nam, i) {  nam <- read.table(filenames[i]) }
> 
> 
> Any help would be very much appreciated.
> 
> Thanks,
> Thomas
> 	[[alternative text/enriched version deleted]]
> 
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> 
>

On Tue, 28 Dec 2004, thomas hills wrote:
> I am wondering if it is possible to read.table repeatedly from a list
> of file names into a new list of table names.
>
> For example:
>
> filenames <- list.files()
>
> then with a function like
>
> rf <- function(i) {
> word??(filename[i]) <- read.table(filenames[i]) }
lapply(filenames, read.table)

will do what I think you want to do.

[It is possible to assign each file to a variable whose name is given by
  another variable, and FAQ 7.21 tells you how, but that probably isn't a
  good idea.]

 	-thomas

thomas hills <thills at mail.utexas.edu> writes:
> I am wondering if it is possible to read.table repeatedly from a list 
> of file names into a new list of table names.
> 
> For example:
> 
> filenames <- list.files()
> 
> then with a function like
> 
> rf <- function(i) {
> word??(filename[i]) <- read.table(filenames[i]) }
> 
> I can't seem to find a function like word?? that will be the object of 
> another operation.   If this worked, then I could repeat it for the 
> length of filenames.
> 
> Also, even the following function seems to give me an error, but I 
> don't yet know why.
> 
> rf <- function(nam, i) {  nam <- read.table(filenames[i]) }
> 
> 
> Any help would be very much appreciated.
Something like

listoftables <- lapply(filenames, read.table)
names(listoftables) <- filenames

might be what you are looking for.

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