R help - Jul 2009 - loading multiple .Rdata and preserving variable names

Dear R-users,

I need to load outputs from multiple previous calculations into one R
session for comparison and (cross-)analysis. The previous calculations are
stored in different directories in .Rdata files (I don't know if this is the
best storage for later usage, but the previous project could be recalculated
and saved into different format, if needed, potentially.)

I can load consequently multiple .Rdata files (in which variable names are
identical), but I don't know how to preserve variables from these files or
make them unique.

I would imagine pointing them as in a list:

# loading 2, max. 4 outputs of previous calculations
load(DataSet1) # VariableA is present
load(DataSet2) # VariableA is present, too

# both VraiableA listed and present
DataSet1$VariableA$parameters
DataSet2$VariableA$parameters

But what is the way to feed all variables into a list? Or more generally,
what is an efficient way to work with multiple separate outputs which one
would like to compare?

(I have read something about environments, but I understood it's only for
functions. I could create environments, but was not succesful in using them
at all (location change or separate sandbox). Functions saveCache,
loadCache, saveObject, loadObject is not really what I have in mind, too --
saveObject(list=ls(), "NewObjectFile") is not a solution either...)

Thanks for any hint in advance.

Cheers, Zroutik

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On 15/07/2009 5:00 AM, ?rout?k wrote:
> Dear R-users,
> 
> I need to load outputs from multiple previous calculations into one R
> session for comparison and (cross-)analysis. The previous calculations are
> stored in different directories in .Rdata files (I don't know if this
is the
> best storage for later usage, but the previous project could be
recalculated
> and saved into different format, if needed, potentially.)
> 
> I can load consequently multiple .Rdata files (in which variable names are
> identical), but I don't know how to preserve variables from these files
or
> make them unique.
> 
> I would imagine pointing them as in a list:
> 
> # loading 2, max. 4 outputs of previous calculations
> load(DataSet1) # VariableA is present
> load(DataSet2) # VariableA is present, too
> 
> # both VraiableA listed and present
> DataSet1$VariableA$parameters
> DataSet2$VariableA$parameters
> 
> But what is the way to feed all variables into a list? Or more generally,
> what is an efficient way to work with multiple separate outputs which one
> would like to compare?
> 
> (I have read something about environments, but I understood it's only
for
> functions. I could create environments, but was not succesful in using them
> at all (location change or separate sandbox). Functions saveCache,
> loadCache, saveObject, loadObject is not really what I have in mind, too --
> saveObject(list=ls(), "NewObjectFile") is not a solution
either...)
Environments are basic in R.  If they are "only for functions",
it's
because everything in R is done by functions.

Given two .RData files, you can load them into separate environments. 
Dealing with conflicting variables names is another issue, of course.

For example:

DataSet1 <- new.env()
load( "somefile", envir=DataSet1)

Now use ls(DataSet1) to see what you've got, repeat for DataSet2, etc. 
You can get a variable as DataSet1$VariableA.

Duncan Murdoch
> 
> Thanks for any hint in advance.
> 
> Cheers, Zroutik
> 
> 	[[alternative HTML version deleted]]
> 
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