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Removing Corrupt file

3 messages · vikrant, Claudia Beleites, David Winsemius

vikrant
# 
Hi 
 I am generating a graph jpeg file using a function R.  I m using this
script
a<- 1:10
b <- 1:10
jpeg("mygraph.jpeg")
{
 plot(a,b)
}
dev.off()


If by some chance I do miss some values suppose for a , the file gets
created initially and then we do not plot anything in it. This file now
becomes corrupted and we cannot delete this file from current R Session.
I Have tried commands like file.remove() and unlink to remove the corrupt
file from current  R session.
Is there any other way inorder to remove such files??



Thanks & Regards,
Vikrant
Claudia Beleites
# 
Vikrant,

if you execute the code inside a function like

jpegplotfun <- function (a, b){
    jpeg("mygraph.jpeg")
    plot(a,b)
    dev.off()
}

the dev.off () is not executed if an error occurs before. So the problem is 
basically that the jpeg file is still open (you may noticed open devices in R as 
left overs of these errors).

See ? try  and ? on.exit for ways to deal with situations where you need to 
clean up after errors.

HTH,

Claudia
On 12/17/2010 08:24 AM, vikrant wrote:

  
    

      
      
    

  


  


      

    

    

      
      

        


  

        

      David Winsemius
    

    

      
      #
    

  


  

      
On Dec 17, 2010, at 2:24 AM, vikrant wrote:

        

            

      
      
      
    

        
This is not making sense, see below.

            

      
      
      
    

        
There was a question earlier this week that may have provoked an  
answer that applies:

?graohics.off  # followed by file.remove()

But I am puzzled. I would not have expected missing values in vectors  
offered to a plot command to have resulted in a corrupted file and I  
am unable to reproduce the behavior when I insert missing values into  
the "a" vector. This suggests you may have more fundamental problems  
with your installation of R (about which you have not provided the  
requested information).