Thank you, Dennis and Petr.
One more question: when aggregating to one es per id, how would I go about
keeping the other variables in the data.frame (e.g., keeping the value for
the first row of the other variables, such as mod2) e.g.:
# Dennis provided this example (notice how mod2 is removed from the output):
> with(x, aggregate(list(es = es), by = list(id = id, mod1 = mod1), mean))
id mod1 es
1 3 1 0.20
2 1 2 0.30
3 2 4 0.15
# How can I get this output (taking the first row of the other variable in
the data.frame):
id es mod1 mod2
1 .30 2 wai
2 .15 4 other
3 .20 1 itas
Thank you,
AC
On Thu, Jan 28, 2010 at 1:29 AM, Petr PIKAL <petr.pi...@precheza.cz> wrote:
> HI
>
> r-help-boun...@r-project.org napsal dne 28.01.2010 04:35:29:
>
> > > Hi All,
> > >
> > > I'm conducting a meta-analysis and have taken a data.frame with
> multiple
> > > rows per
> > > study (for each effect size) and performed a weighted average of
> effect
> > > size for
> > > each study. This results in a reduced # of rows. I am particularly
> > > interested in
> > > simply reducing the additional variables in the data.frame to the
> first row
> > > of the
> > > corresponding id variable. For example:
> > >
> > > id<-c(1,2,2,3,3,3)
> > > es<-c(.3,.1,.3,.1,.2,.3)
> > > mod1<-c(2,4,4,1,1,1)
> > > mod2<-c("wai","other","calpas","wai","itas","other")
> > > data<-as.data.frame(cbind(id,es,mod1,mod2))
>
> Do not use cbind. Its output is a matrix and in this case character
> matrix. Resulting data frame will consist from factors as you can check by
>
>
> str(data)
>
> data<-data.frame(id=id,es=es,mod1=mod1,mod2=mod2)
>
>
> > >
> > > data
> > >
> > > id es mod1 mod2
> > > 1 1 0.3 2 wai
> > > 2 2 0.1 4 other
> > > 3 2 0.2 4 calpas
> > > 4 3 0.1 1 itas
> > > 5 3 0.2 1 wai
> > > 6 3 0.3 1 wai
> > >
> > > # I would like to reduce the entire data.frame like this:
>
> E.g. aggregate
>
> aggregate(data[, -(3:4)], data[,3:4], mean)
> mod1 mod2 id es
> 1 4 calpas 2 0.3
> 2 1 itas 3 0.2
> 3 1 other 3 0.3
> 4 4 other 2 0.1
> 5 1 wai 3 0.1
> 6 2 wai 1 0.3
>
> doBy or tapply or ddply from plyr library or ....
>
> Regards
> Petr
>
> > >
> > > id es mod1 mod2
> > >
> > > 1 .30 2 wai
> > > 2 .15 4 other
> > > 3 .20 1 itas
> > >
> > > # If possible, I would also like the option of this (collapsing on id
> and
> > > mod2):
> > >
> > > id es mod1 mod2
> > > 1 .30 2 wai
> > > 2 0.1 4 other
> > > 2 0.2 4 calpas
> > > 3 0.1 1 itas
> > > 3 0.25 1 wai
> > >
> > > Any help is much appreciated!
> > >
> > > AC Del Re
> > >
> >
> > [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> > and provide commented, minimal, self-contained, reproducible code.
>
>
[[alternative HTML version deleted]]
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
