[R] Any existing functions for reading and extracting data from path names?

[Mikhail Titov]

I'm not sure what you are trying to achieve, but I think this can be a good
starting point:

files <- list.files("deleteme", full.names=TRUE, recursive=TRUE)
names <- sapply(strsplit(files, "/", TRUE), "[", 2)
x <- lapply(files, function(f) {
    out <- read.csv(f)
    out$city <- strsplit(f, "/", TRUE)[[1]][2]
    out
    })
y <- do.call("rbind", x)

Mikhail

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Ista Zahn
> Sent: Friday, March 11, 2011 10:53 AM
> To: r-help at r-project.org
> Subject: [R] Any existing functions for reading and extracting data
> from path names?
> 
> Hi helpeRs,
> 
> I have inherited a set of data files that use the file system as a
> sort of poor man's database, i.e., the data files are nested in
> directories that indicate which city they come from. For example:
> 
> dir.create("deleteme")
> for(i in paste("deleteme", c("New York", "Los Angeles"), sep="/")) {
>     dir.create(i)
>     for(j in paste("data", 1:2, ".csv", sep="")) {
>         write.csv(data.frame(x=1:10), file=paste(i, j, sep="/"))
>     }
> }
> 
> list.files("deleteme", recursive=TRUE)
> 
> What I want to end up with is
> 
>   x        city wave
>   1    New York    1
>   1 Los Angeles    1
>   1    New York    2
>   1 Los Angeles    2
> 
> I've started writting a simple function to do this, but it seems like
> a common situation and I'm wondering if there are any packages or
> functions that might make this easier.
> 
> Thanks!
> Ista
> --
> Ista Zahn
> Graduate student
> University of Rochester
> Department of Clinical and Social Psychology
> http://yourpsyche.org
> 
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