[R] Testing for the existence of a file.

[Joerg Maeder]

hello

try this :  system('ls tmp.tmp',T)
it will return the filename (in this examplte tmp.tmp) if the file exist 
or character(0) if not

to change the return value to True/False you can use the following code

as.numeric(system('ls tmp.tmp |wc -l',T))>0

Rolf Turner wrote:
> 
> Is there any way to do this (test for the existence of a file)
> in R?  In Splus (3.4) I can do
> 
>         unix(paste("test -r", fnm), output = F)
> 
> where ``fnm'' is a character string giving the pathname of the file.
> 
> This returns 0 if the file exists and 256 if it doesn't.
> 
> I thought in R to do something like
> 
>         system(paste("test -r", fnm), intern =T)
> 
> but this returns ``character(0)'' irrespective of the existence of
> the file.
> 
> Any ideas?
> 
>                                         cheers,
> 
>                                                 Rolf Turner
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-- 
    Joerg Maeder             IACETH              INSTITUTE
   PhD Student                              FOR ATMOSPHERIC 
  Phone: +41 1 633 36 25                 AND CLIMATE SCIENCE
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