Thanks Jim, but I still got the problem that the pre-processing becomes way
too computationally expensive. R seems to handle characters and factors much
much worse than numeric IDs. I don't have enough RAM to even write the file
when they are viewed as chars instead of numeric values!

Anyone have any other ideas? Is it not possible to tell R not to rewrite
upon import? It wouldn't matter if it only would write the correct IDs to
the exported csv file, but it exports the abbreviated version which is of no
use.

Mike

On Sat, Oct 23, 2010 at 3:56 AM, jim holtman <jholtman@gmail.com> wrote:

> Your best bet is to make sure that you read the IDs in as characters.
> If they are being read in as floating point numbers, then there is
> only 15 digits of accuracy, so if you have IDs 18-22 digits, you will
> be missing data.  So if you are using read.table, then look at
> colClasses to see how to do this.
>
> Provide a subset of your data and the statements that you are using to
> read in the data.
>
> On Fri, Oct 22, 2010 at 1:15 PM, ZeMajik <zemajik@gmail.com> wrote:
> > Hey,
> >
> > I'm using R as a pre-processor for a large dataset with IDs which are
> > numeric (but has no numeric meaning so can be seen as factors).
> > I do some data formating and then write it out to a csv file.
> >
> > However the problem is that the IDs are very long, 18-22 chars long more
> > precisely. R is constantly rewriting these IDs to the abbreviated +eX
> which
> > hinders me from exporting the data to the csv since the IDs are no longer
> > intact.
> > I've tried telling R that ID column is a factor, but this results in two
> > problems: 1) Since I have millions of rows and R is slower handling
> factors
> > than numbers my comp can't run the process in any kind of reasonable
> time.
> > and 2) Some IDs STILL seem to be rewritten somehow. The second point made
> me
> > believe that perhaps R is rewriting upon import?
> >
> > Does anyone have any tips on how to solve this problem?
> >
> > Thanks,
> > Mike
> >
> >        [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
>
>
> --
> Jim Holtman
> Cincinnati, OH
> +1 513 646 9390
>
> What is the problem that you are trying to solve?
>

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