[R] DBM databases for R?

[Prof Brian D Ripley]

On Mon, 28 Jan 2002, Petra Steiner wrote:

> Hello,
>
> > Unfortunately, I don't think that's what the OP is looking for - by DBM
> > databases she probably means Berkeley-style database files, for which (as
>
> that is what I meant indeed. I hoped I could use this mode of storing large
> data for the import of my matrix stuff.  Writing out to a file which R could
> read would be of no improvement, for this is what my program is doing at the
> moment by scan.

*But* you don't need to write an ASCII file as readBin can read from binary
files (already a big win) and you can avoid the file altogether by
using a pipe or fifo if space were an issue (unlikely).

There's also RSPerl, which should enable you to share binary Perl objects.

For large matrices it is hard to see how anything will do much better than
using binary files, which are pretty close to a dump of the internal
representation.  Much of the apparent slowness of R in data input comes
from people using methods designed for data frames on matrices.

-- 
Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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