R help - Jun 2012 - Feature request: 'file.path()' accepting an input vector

Dear list,

I have a small feature request regarding the implementation of 
'file.path()':

It'd be great if 'file.path()' would allow to specify an input
*vector*
instead of solely rely on a specification via the three dot argument.

AFAIU, currently it's only possible to "manually" specify each
path
component via the three dot argument:
 > file.path(letters[1], letters[2], letters[3])
[1] "a/b/c"

Providing a vector object will result in the same vector being returned, 
instead of a slash separated scalar:
 > file.path(letters[1:3])
[1] "a" "b" "c"

It'd be great if the last call would have this result:
 > file.path(letters[1:3])
[1] "a/b/c"

If that's already possible, I'd appreciate a pointer. If not: thanks a 
lot for considering this,

Best regards,
Janko

On 28/06/2012 10:40, Janko Thyson wrote:
> Dear list,
>
> I have a small feature request regarding the implementation of
> 'file.path()':
Clearly you have not read where and how to make feature requests 
(R-devel list or Wishlist on bugs.r-project.org).
>
> It'd be great if 'file.path()' would allow to specify an input
*vector*
> instead of solely rely on a specification via the three dot argument.
>
> AFAIU, currently it's only possible to "manually" specify
each path
> component via the three dot argument:
>  > file.path(letters[1], letters[2], letters[3])
> [1] "a/b/c"
>
> Providing a vector object will result in the same vector being returned,
> instead of a slash separated scalar:
>  > file.path(letters[1:3])
> [1] "a" "b" "c"
>
> It'd be great if the last call would have this result:
>  > file.path(letters[1:3])
> [1] "a/b/c"
>
> If that's already possible, I'd appreciate a pointer. If not:
thanks a
> lot for considering this,
It's not going ever to be possible: it does what it is intended and 
documented to do with a single vector, and people rely on the existing 
behaviour. OTOH

paste(x, collapse="/")

does what you want (you could use .Platform$file.sep for maximal 
portability).  Or you could use do.call(file.path, as.list(x))

>
> Best regards,
> Janko

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595