I am looking for an answer to a similar question - a generalized
solution that would be able to apply
(1) any number of functions
(2) to any number of vectors
(3) by any number of factors
(just like SQL's group by).
The output data frame must contain the values of the by factors, to be
used for joins.
Aggregate() does (2) and (3). The solutions posted to this thread
(split+sapply, by, tapply) do (1) and (3) (or so it seems to me). What
would be the best way to get to (1)+(2)+(3)?
I am inclined to use aggregate() in a loop with
eval(parse(text="aggregate expression here")).
Running
groupby <- do.call("rbind", by(var_i, list(a,b,c,d,e,f),
function(x) c(fct1(x),fct2(x),fct3(x),fct4(x))))
in a loop (var_1, var_2 etc) would be very nice but I don't know how
to add a-f as columns in the output data frame.
Thank you,
b.
On Mon, 2005-03-28 at 19:15 -0600, Sivakumaran Raman wrote:
> I have the data similar to the following in a data frame:
> LastName Department Salary
> 1 Johnson IT 56000
> 2 James HR 54223
> 3 Howe Finance 80000
> 4 Jones Finance 82000
> 5 Norwood IT 67000
> 6 Benson Sales 76000
> 7 Smith Sales 65778
> 8 Baker HR 56778
> 9 Dempsey HR 78999
> 10 Nolan Sales 45667
> 11 Garth Finance 89777
> 12 Jameson IT 56786
>
> I want to calculate both the mean salary broken down by Department and
> also the
> total amount paid out per department i.e. I want both sum(Salary) and
> mean(Salary) for each Department. Right now, I am using aggregate.data.frame
> twice, creating two data frames, and then combining them using data.frame.
> However, this seems to be very memory and processor intensive and is
> taking a
> very long time on my data set. Is there a quicker way to do this?
>
> Thanks in advance,
> Siv Raman
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
>
______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
______________________________________________
R-help@stat.math.ethz.ch mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
