[R] sum specific rows in a data frame

[hadley wickham]

On Thu, Apr 15, 2010 at 1:16 AM, Chuck <vijay.nori at gmail.com> wrote:
> Depending on the size of the dataframe and the operations you are
> trying to perform, aggregate or ddply may be better.  In the function
> below, df has the same structure as your dataframe.

Current version of plyr:

         agg  ddply
X10    0.005  0.007
X100   0.007  0.026
X1000  0.086  0.248
X10000 0.577  3.136
X1e.05 4.493 44.147

Development version of plyr:

         agg ddply
X10    0.003 0.005
X100   0.007 0.007
X1000  0.042 0.044
X10000 0.410 0.443
X1e.05 4.479 4.237

So there are some big speed improvements in the works.

Hadley


-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/