importing data
Hi Ray, Comments below:
On 26 January 2013 09:03, Ray Cheung <ray1728 at gmail.com> wrote:
[snip]
###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
}
Too complex. Why not just use file.exists directly?
###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
}
Too complex here too. I suggest something like:
M <- list()
for (i in 1:n) {
file_name <- paste0("C:/.../data", n, ".dat")
if (file.exists(file_name)) M[i] <- read.table(file_name) } R gurus don't like for() loops, but they are easy for humans to understand. If this doesn't work, post the error message.
Thanks for all comments. Best Regards, Ray On Fri, Jan 25, 2013 at 5:48 PM, Ivan Calandra <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 ivan.calandra at u-bourgogne.fr http://biogeosciences.u-**bourgogne.fr/calandra<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> 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
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