[R] problem of data manipulation

Matthew Dowle mdowle at mdowle.plus.com
Wed Jan 20 15:43:52 CET 2010


Sounds like a good idea. Would it be possible to give an example of how to 
combine plyr with data.table, and why that is better than a data.table only 
solution ?

"hadley wickham" <h.wickham at gmail.com> wrote in message 
news:f8e6ff051001200624r2175e38xf558dc8fa3fb6a3c at mail.gmail.com...
> Note that in the documentaton ?"[.data.table" where I say that 'by' is 
> slow,
> I mean relative to how fast it could be. Its seems, in this specific
> example anyway, and with the code posted so far, to be significantly 
> faster
> than sqldf and plyr.

Of course the best of both worlds would be to use data table within
plyr to get both speed and a consistent syntax for other types of
split-apply-combine tasks.

Hadley


-- 
http://had.co.nz/



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