How to obtain a list of directories within a direc

Question

This may be a very easy question for someone - I am able to use list.files() to obtain a list of files in a given directory, but if I want to get a list of directories, how would I do this? Is it somehow right in front of me as an option within list.files()?

Also, I'm using Windows, so if the answer is to shell out to some Linux/unix command, that won't work for me.

.NET for example has a Directory.GetFiles() method, and a separate Directory.GetDirectories() method, so I figured R would have an analogous pair. Thanks in advance.

Answer 1

What about something like this, give it a try:

dir('.')[file.info(dir('.',full.names=T))$isdir]

Answer 2

list.dirs <- function(...) {
    x <- dir(...)
    x[file_test("-d", x)]
}

might be of use?

How might we do this recursively? (the recursive argument of dir breaks these functions because it never returns directory names, just the files within each directory, etc...).

Answer 3

base R now includes a list.dirs function, so home-brewed variants are no longer necessary.

For example:

list.dirs('.', recursive=FALSE)

Answer 4

Update: A list.dirs function was added to the base package in revision 54353, which was included in the R-2.13.0 release in April, 2011.

list.dirs(path = ".", full.names = TRUE, recursive = TRUE)

So my function below was only useful for a few months. :)

---

I couldn't find a base R function to do this, but it would be pretty easy to write your own using:

dir()[file.info(dir())$isdir]

Update: here's a function (now corrected for Timothy Jones' comment):

list.dirs <- function(path=".", pattern=NULL, all.dirs=FALSE,
  full.names=FALSE, ignore.case=FALSE) {
  # use full.names=TRUE to pass to file.info
  all <- list.files(path, pattern, all.dirs,
           full.names=TRUE, recursive=FALSE, ignore.case)
  dirs <- all[file.info(all)$isdir]
  # determine whether to return full names or just dir names
  if(isTRUE(full.names))
    return(dirs)
  else
    return(basename(dirs))
}

Answer 5

I had this problem a while back and used this recursive code to find all directories. Perhaps this can be of use?

list.dirs <- function(parent=".")   # recursively find directories
{
    if (length(parent)>1)           # work on first and then rest
        return(c(list.dirs(parent[1]), list.dirs(parent[-1])))
    else {                          # length(parent) == 1
        if (!is.dir(parent))
            return(NULL)            # not a directory, don't return anything
        child <- list.files(parent, full=TRUE)
        if (!any(is.dir(child)))
            return(parent)          # no directories below, return parent
        else 
            return(list.dirs(child))    # recurse
    }
}

is.dir <- function(x)    # helper function
{
    ret <- file.info(x)$isdir
    ret[is.na(ret)] <- FALSE
    ret
}

Answer 6

You mention that you don't want to shell out to a Linux/UNIX command but I assume its ok to shell out to a Windows command. In that case this would do it:

shell("dir/ad/b", intern = TRUE)

and this would do it recursively:

shell("dir/ad/b/s", intern = TRUE)

Normally I would prefer the platform independent solutions of others here but particularly for interactive use where you are just concerned with getting the answer as simply and directly as possible this may be less work.