[R] merge data frames taking mean/mode of multiple macthes
Christoph Buser
buser at stat.math.ethz.ch
Mon Jan 17 18:19:41 CET 2005
Dear Avneet
the function aggregate (see also ?aggregate) could be useful for
your problem. See the short example I've written below.
dat1 <- data.frame(lot = factor(1:10),y1 = rnorm(10))
str(dat1)
dat2 <- data.frame(nr = 1:100, lot = factor(rep(1:10, each = 10)),y2 = rnorm(100))
str(dat2)
dat2.agr <- aggregate(dat2$y, by = list(lot = dat2$lot), FUN = mean)
names(dat2.agr)[2] <- "y2"
dat.mer <- merge(dat1, dat2.agr)
str(dat.mer)
Be careful about merging dataframes. There should always be a
control that the right cases are merged together.
Regards,
Christoph Buser
--
Christoph Buser <buser at stat.math.ethz.ch>
Seminar fuer Statistik, LEO C11
ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND
phone: x-41-1-632-5414 fax: 632-1228
http://stat.ethz.ch/~buser/
avneet singh writes:
> Hello :)
>
> I have two data frames, one has properties taken on a
> piece by piece basis and the other has performance on
> a lot by lot basis. I wish to combine these two data
> frames but the problem is that each lot has multiple
> pieces and hence i need to take a mean of the
> properties of multiple pieces and match it to the row
> having data about the lot.
>
> I was wondering if there is a simple commmand, an
> extension of "merge", or an option of merge i do not
> know which could easily do this work.
>
> Thank you :)
>
> =====
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--
Christoph Buser <buser at stat.math.ethz.ch>
Seminar fuer Statistik, LEO C11
ETH (Federal Inst. Technology) 8092 Zurich SWITZERLAND
phone: x-41-1-632-5414 fax: 632-1228
http://stat.ethz.ch/~buser/
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