[R] Problems with environmental variables set with Sys.putenv

[David Kane <David Kane]

Hi,

I see some weird behavior when loading a specific dataframe after changing the value of
an enviroment variable using Sys.putenv(). Alas, I can't reproduce it from an
arbitrary dataframe. Here is the session:

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Version 1.2.3  (2001-04-26)

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Type `q()' to quit R.

[Previously saved workspace restored]

> Sys.getenv("MODE")
        MODE 
"PRODUCTION" 
> ls()
character(0)
> load("~/data/latest/R/Factors.Rdata")
> ls()
[1] "Factors"
> Sys.getenv("MODE")
        MODE 
"PRODUCTION"					


##################

So far, so good. Loading a dataframe shouldn't, I think, effect the setting of
an environment variable under any (?) circumstances. Just to be sure, I load it
a couple more times.

#################

> load("/home/a296180/data/latest/R/Factors.Rdata")
> Sys.getenv("MODE")
        MODE 
"PRODUCTION" 
> load("/home/a296180/data/latest/R/Factors.Rdata")
> Sys.getenv("MODE")
        MODE 
"PRODUCTION" 

#################

Now I change the setting of the environment variable, and load the dataframe
again. Everything is fine, but when I load it a second time, the value of $MODE
gets set to missing!

################

> Sys.putenv("MODE"="TEST")
> Sys.getenv("MODE")
  MODE 
"TEST" 
> load("/home/a296180/data/latest/R/Factors.Rdata")
> Sys.getenv("MODE")
  MODE 
"TEST" 
> load("/home/a296180/data/latest/R/Factors.Rdata")
> Sys.getenv("MODE")
MODE 
  "" 
#################

At this point, I am stumped. As I mentioned, I have been unable to make this
occur with an arbitrary dataframe. With most (AFAIK all) of my other dataframe,
this does not occur. If there was interest, I would be happy to submit this as
a bug report and/or pass along the offending dataframe. But, my first thought
is that I am missing something . . .

Thanks for any help,

Dave Kane


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