R help - Jul 2012 - why does this simple example NOT work?

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=""))

Do you know any workaround? I am already out of ideas.

Best regards,

Martin

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=""))
> 
> Do you know any workaround? I am already out of ideas.
> 
You haven't given the error message R provides.
Carefully read the documentation of save.

save(list=paste("a", 1, sep=""),
file=paste(paste("a", 1, sep=""), ".RData",
sep=""))

This "works" for for me.

Berend




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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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