Dear all,

 

I have come across some Windows Script code which calls the
"file.exists" function in R to check for the existence of a particular
file on an R server. This is what the code looks like:

 

            do

            {

                        // some useful code

            }

            while (m_workspace.session.eval("file.exists(" + dataFile +
")") != "1");

 

It appears that the behavior of this code is different when used with R
version 2.1.1 compared to R version 1.9.1. If the compare statement s is
changed from

 

            while (s != "1")

to

            while (s != "True")

or

            while !(s)

 

the behavior of the code is the same with both versions of R.

 

After reading the R documentation, I have not found any evidence that
the original syntax (s != "1") is in any way recommended or supported
(in version 2.1.1). Still, my questions are:

 

1. Is it possible that the syntax has been supported in older versions
of R?

2. Is the reason for the recent change in behavior known and documented
anywhere?

 

I have been unable to find an answer to either question, so any
information about this would be appreciated.

 

Thanks,

 

T. Andersson


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