R packages - Feb 2004 - Package "ref" implements references and referenceable data.frames for the S-language

Repeatedly people have asked how to pass arguments by reference in R.

Now package "ref"  is on CRAN, which provides two referencing methods:

Functions ref(), deref() and friends conveniently allow to pass parameters
"by reference" instead of  "by value". This can be useful in
memory critical
applications but requires a more careful programming style to track the
implications of functions changing their parameters. However, package ref is
written in pure S and attaching this package does not change any standard S
behaviour. 

Class refdata is a transparent wrapper to matrices and data.frames which
allows for memory efficient nested subsetting. I.e. you can create a subset
of a
subset ... of a data.frame without duplicating the data in memory, instead
only indexing information is duplicated. Indexing information is represented
as positive or negative integers, whatever is shorter, thus the length of
the
index is granted to be <=nrows/2 resp. <=ncol/2. Memory savings in case of
a
square data.frame is roughly n^2-n elements per level of nested subsetting.

This code is offered "as is" under the GPL, usage is completely at
your own
risk. (Some efforts has been put in the included regression tests to make
shure
the code does what it is intended to do).

Feedback about problems or successful example uses is welcome.
Please use the email address given in the package DESCRIPTION and please
don't cc to lists for spam prevention.

Best regards


Jens Oehlschl?gel

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