Context: I'm relatively new to R and am working with very large datasets.
General problem: If working on a dataset requires that I produce more than
two objects of roughly the size of the dataset, R quickly uses up its
available memory and slows to a virtual halt.
My tentative solution: To save and remove objects as they're created, and
load them when I need them. To do this I'm trying to automatically
generate file names derived from these objects, and use these in save().
My specific question to the list: How do I capture the string that names
an object I want to save, in such a way that I can use it in a function
that calls save()?
For example, suppose I create a matrix and then save it follows:
> mat<-matrix(1:9,3,3)
> save(mat, file="matfile")
Then I get a file of the kind I'd like: the command 'load("matfile")'
retrieves the correct matrix, with the original name 'mat'.
Further, if I instead save it this way:
> objectname<-"mat"
> save(list=ls(pattern=objectname), file="matfile")
then I get the same positive result.
But now suppose I create a function
> saveobj <- function(objectname,objectfile)
+ {
+ save(list=ls(pattern=objectname),file=objectfile);
+ return()};
Then if I now try to save 'mat' by
> matname<-"mat"
> saveobj(matname,"matfile")
I do not get the same result; namely, the command 'load("mat")' retrieves
no objects. Why is this?
I'd be grateful for any help on either my specific questions, or
suggestions of a better ways to address the issue of limited memory.
Thanks,
David Romano
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