RE: [R] Aggregating data (with more than one function)

From: Liaw, Andy <andy_liaw_at_merck.com>
Date: Tue 29 Mar 2005 - 11:45:00 EST


Here's one possible way, using the data you supplied:

> dat <- read.table("clipboard", header=T, row=1)
> do.call("rbind",by(dat$Salary, dat$Department, function(x) c(mean=mean(x),

total=sum(x))))

            mean total

Finance 83925.67 251777
HR      63333.33 190000
IT      59928.67 179786
Sales   62481.67 187445

If you need the department names as a variable, you can add that easily.

HTH,
Andy

> From: Sivakumaran Raman
>

> 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
>
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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 Received on Tue Mar 29 11:52:13 2005

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