[R] importing many csv files into separate matrices

[Greg Snow]

As you have noticed, using assign is not simple, and your approach has
potential to cause even more problems even if you get it working.
Here is another approach:

loadCSVfiles <- function(path) {
  x <- list.files(path, full.names=TRUE)
  out <- lapply( x, read.csv )
  names(out) <- sub(pattern="\\.csv$", replacement="", x)
  out
}

then run:

mydata <- loadCSVfiles("/my/path")

and mydata will be a list with all of your data objects with the
desired names.  You can do things like:

plot(mydata$alaska)

or

with(mydata, plot(alaska))

or

lapply( mydata, plot )

etc.

This approach does not place the individual objects into the global
workspace, but that is a good thing.

On Wed, Nov 27, 2013 at 3:39 PM, yetik serbest <yserbest at prodigy.net> wrote:
> Hi Everyone,
>
> I am trying to import many CSV files to their own matrices. Example, alaska_93.csv to alaska. When I execute the following, for each csv.file separately it is successful.
>
> singleCSVFile2Matrix <- function(x,path) {
>  assign(gsub(pattern=".csv",x,replacement=""),read.csv(paste(path,x,sep="")))
> }
>
> when I try to include it in a loop in another function (I have so many csv files to import), it doesn't work. I mean the following function doesn't do it.
>
> loadCSVFiles_old <- function(path) {
>  x <- list.files(path)
>  for (i in 1:length(x)) {
>   assign(gsub(pattern=".csv",x[i],replacement=""),read.csv(paste(path,x[i],sep="")))
>   }
> }
>
> Instead, if I execute the foor loop in the command line, it works. I am puzzled. Appreciate any help.
>
> thanks
> yetik
>
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-- 
Gregory (Greg) L. Snow Ph.D.
538280 at gmail.com