R devel - Jan 2014 - file.exists does not like path names ending in /

If a path name ends in slash then file.exists says it does not exist.
I would have expected these to all return TRUE.
> file.exists("/Program Files")
[1] TRUE
> file.exists("/Program Files/")
[1] FALSE
> file.exists(normalizePath("/Program Files/"))
[1] FALSE
> R.version.string
[1] "R version 3.0.2 Patched (2013-11-25 r64299)"

I am using Windows 8.1 .

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email: ggrothendieck at gmail.com

On 17.01.2014 06:10, Gabor Grothendieck wrote:
> If a path name ends in slash then file.exists says it does not exist.
> I would have expected these to all return TRUE.
>
>> file.exists("/Program Files")
> [1] TRUE
>> file.exists("/Program Files/")
> [1] FALSE
>> file.exists(normalizePath("/Program Files/"))
> [1] FALSE
>> R.version.string
> [1] "R version 3.0.2 Patched (2013-11-25 r64299)"
>
> I am using Windows 8.1 .
>

See ?file.exists:

"(However, directory names must not include a trailing backslash or 
slash on Windows.)"

Note also that  "/Program Files" is not safe anyway since it is
relative
to the current drive.

Best,
Uwe Ligges

>>>>> Gabor Grothendieck <ggrothendieck at gmail.com>
>>>>>     on Fri, 17 Jan 2014 00:10:43 -0500 writes:
    > If a path name ends in slash then file.exists says it does
    > not exist.  I would have expected these to all return
    > TRUE.

    >> file.exists("/Program Files")
    > [1] TRUE
    >> file.exists("/Program Files/")
    > [1] FALSE
    >> file.exists(normalizePath("/Program Files/"))
    > [1] FALSE
    >> R.version.string
    > [1] "R version 3.0.2 Patched (2013-11-25 r64299)"

I would also have expected all these to work,
but that is only because I do not use Windows;
indeed, for me  (Linux Fedora 19, but I'm pretty sure *any*
version):

  > dir.create("/tmp/foo bar")
  > normalizePath("/tmp/foo bar/")
  [1] "/tmp/foo bar"
  > file.exists("/tmp/foo bar/")
  [1] TRUE
  > file.exists(normalizePath("/tmp/foo bar/"))
  [1] TRUE
  > 


    > I am using Windows 8.1 .

poor you  ;-)   yes, don't take it personally

Last but not least   ?file.exists   in its  'Details' section
mentions several times how Windows behaves differently from the 
civilized world (:-)
notably that it also says 

  (However,
     directory names must not include a trailing backslash or slash on
     Windows.)

So, all seems as documented, but unfortunately your (and most
probably not only yours !!) expectations are different.
I agree that this is quite unfortunate, and we all would be
happy if OSes were consistent here.

I wonder if R couldn't help you (and many others) better to
gloss over these OS differences in a helpful way.
This list may be a good place to discuss such proposals ...

Martin

-- 
Martin Maechler ETH Zurich -- and R Core Team