[R] Finding a folder at the root level of an unknown drive

Duncan Murdoch murdoch at stats.uwo.ca
Sat Jun 6 16:39:22 CEST 2009


On 06/06/2009 9:19 AM, Dennis Fisher wrote:
> Colleagues,
> 
> R 2.9.0
> Windows XP
> 
> Task is as follows:
> A folder FOLDERNAME exists at the root level of some drive, e.g., E: 
> \FOLDERNAME
> I want to search all possible drives to find the location of this  
> folder but I don't know what drives exist or are mounted.
> 
> The command:
> 	dir(path="C:/", pattern=FOLDERNAME)
> happens to be successful.
> 
> However, the command:
> 	dir(path="C:/", pattern=FOLDERNAME)
> results is a pop-up message:
> 	"There is no disk in the drive.  Please insert a disk into drive D:"
> 
> Can I avoid the pop-up message?  i.e., can I execute a command that  
> silently reports only successes?

I think that's quite hard, because the action on failure depends on the 
drive type.  It's coming from the device driver, not from R.  I'd guess 
your drive D: is a CD drive, for example.  If you do the same with Z:/ 
(assuming you don't have a drive Z: defined), you won't get the popup, 
but you'll get a warning from R because Z:/ is not readable.

So to do this, you'd need code to recognize what kind of drive you had, 
what sort of problems there could be, and avoid triggering them.

Duncan Murdoch




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