[R] using the system command

Data Analytics Corp. walt at dataanalyticscorp.com
Wed Sep 28 18:05:28 CEST 2011


I started playing around with a function for using StatTransfer (version 
10) for importing data.  This started as a simple task but it's not 
working and so now I'm very frustrated.  I'm using R version 2.13 on 
Windows 7.

The function, called fn.importData,  is:

         function(file = NULL, type = NULL){
             ##  create statTransfer command file - stcmd
             ext <- switch(type, sas = "sas7bdat", excel = "xls")
             tmp <- paste("copy C:\\Temp\\", file, ".", ext, " r 
c:\\temp\\", file, ".rdata -T > ", file, " \n\nquit", sep = "")
             cat(tmp, file = "c:/temp/transfer.stcmd", append = FALSE)
             ##  transfer using StatTransfer
             system(paste('"c:\\program files\\statTransfer10\\st.exe"', 
'c:\\temp\\transfer.stcmd'), wait = FALSE)
             ##  load
             inpt <- paste("c:\\temp\\", file, ".RData", sep = "")
             load(inpt, .GlobalEnv)

My call using a sas file (vicks.sasa7bdat) is:

         fn.importData(file = "vicks", type = "sas")

The StatTransfer command file is created and StatTransfer is called 
correctly.  The translation from vicks.sas7bdat  to vicks.RData occurs 
as it should - I can look at them in the temp directory.  But I get an 
error message for the load function:

         Error in readChar(con, 5L, useBytes = TRUE) : cannot open the 
         In addition: Warning message:
         In readChar(con, 5L, useBytes = TRUE) :
         cannot open compressed file 'c:\temp\vicks.RData', probable 
reason 'No such file or directory'

If I uncomment the return(inpt) statement in the above function and use 
the following at the command line:

         load(fn.importData(file = "vicks", type = "sas"))

then everything works fine.  But of course I don't want to do this.  Any 
suggestions as to what I'm doing wrong?  Why the error message?

Also, the StatTransfer program sometimes fails to close so if I 
repeatedly call my function I'll have multiple occurrences of 
StatTransfer running.  How can I force it to close after the transfer?




Walter R. Paczkowski, Ph.D.
Data Analytics Corp.
44 Hamilton Lane
Plainsboro, NJ 08536
(V) 609-936-8999
(F) 609-936-3733
walt at dataanalyticscorp.com

More information about the R-help mailing list