[R] why does this simple example NOT work?

Duncan Murdoch murdoch.duncan at gmail.com
Fri Jul 20 13:22:03 CEST 2012

On 12-07-20 2:50 AM, Martin Ivanov wrote:
>   Hello,
> I want to create and save objects in a loop, but this is precluded by the following obstacle:
> this part of the script fails to work:
> assign(x=paste("a", 1, sep=""), value=1);
> save(paste("a", 1, sep=""), file=paste(paste("a", 1, sep=""), ".RData", sep=""))

paste("a", 1, sep="") is equivalent to "a1".  So you are saving the 
string "a1" to the file "a1.RData".  You presumably want to save the 
value of the variable a1, not that string.  (Though you didn't say that. 
  It's helpful to describe what you don't like, don't just say it "fails 
to work".)

If you have the name of a variable in a string, you can use get() to get 
the value.  So I think this code would do what you want:

name <- paste0("a", 1)
assign(x=name, value=1)
save(get(name), file=paste0(name, ".RData"))

(If you don't have the paste0 function, you should upgrade to the 
current R version.)

Duncan Murdoch

> Do you know any workaround? I am already out of ideas.
> Best regards,
> Martin
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