[Rd] stringsAsFactors = FALSE
Peter Dalgaard
p.dalgaard at biostat.ku.dk
Mon Nov 17 18:43:16 CET 2008
William Dunlap wrote:
>> but I'm not sure why they are being converted to factors in
>> the first place.
>
> I think expand.grid converts input strings to factors so they
> retain the order they have in the input.
Yep. These things do matter. Incidentally, I recently got burned by
cooking an example using expand.grid, writing the data to a file with
write.table and reading it back in during lecture with read.table. Odds
ratio turned upside down...
--
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