summaryBy(): Is it the best option?

Hi

I did not see any answer yet so I try. You can use aggregate, by or 
sapply.

Something like
aggregate(soc6a[, your columns], list(hh=hh), sum, na.rm=T)
by(soc6a[, your columns], hh, sum, na.rm=T)
sapply(split(soc6a[, your columns], hh), sum, na.rm=T)

But you have to check speed gain by yourself.

HTH
Petr

Date sent:      	Tue, 5 Dec 2006 01:30:50 +0100 (CET)
From:           	Werner Wernersen <pensterfuzzer at yahoo.de>
To:             	r-help at stat.math.ethz.ch
Subject:        	[R] summaryBy(): Is it the best option?

Hi,

since I have quite large tables and the processing
takes quite a while I am
curious if I can improve the performance of this
aggregation somehow: At the 
moment I am using summaryBy from the doBy package
under R 2.4.0, Win2K.

summaryBy(soc_s6aq5 + soc_s6aq7 + soc_s6aq9 +
soc_s6aq11 ~ hh + 
comgroup,soc6a,postfix=c("","","",""),FUN=sum,
na.rm=T)

The data.frame has 124100 rows and 13 cols.

Thanks for any hints!

Werner

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Petr Pikal
petr.pikal at precheza.cz