Hi Eik, 

thank you so much - it works perfectly!

Thank you and best wishes

Alain


 

Eik Vettorazzi <E.Vettorazzi@uke.de> hat am 6. Februar 2013 um 17:01 geschrieben:
> Hi Alain,
> here is a one-liner for a df without the rowSum column
> 
> df<-data.frame(id=c("x01","x02","x03","x04","x05","x06"),a=c(1,2,NA,4,5,6),b=c(2,4,6,8,10,NA),c=c(NA,3,9,12,NA,NA))
> 
> (df$wSum<-apply(sweep(df[,-1],1,rowSums(df[,-1],na.rm=T),"/"),1,function(x)sum(x*w,na.rm=T)))
> 
> hth.
> 
> Am 06.02.2013 14:17, schrieb D. Alain:
> > Dear R-List, 
> > 
> > 
> > I am sure there must be a very simple way to do this - I just do not know how...
> > This is what I want to do: 
> > 
> > 
> > #my dataframe
> > 
>
 > 
df<-data.frame(id=c("x01","x02","x03","x04","x05","x06"),a=c(1,2,NA,4,5,6),b=c(2,4,6,8,10,NA),c=c(NA,3,9,12,NA,NA),sum=c(3,9,15,24,15,6))
> > 
> > id a b c sum
> > 1 x01 1 2 NA 3
> > 2 x02 2 4 3 9
> > 3 x03 NA 6 9 15
> > 4 x04 4 8 12 24
> > 5 x05 5 10 NA 15
> > 6 x06 6 NA NA 6
> > 
> > 
> > #my weights
> > w<-c(10.5,9,12.8)
> > 
>
 > #now I want to calculate the proportion of the rowsum = "sum" of 
every other number in the row, that is df[1,2]/df[1,5], df[1,3]/df[1,5],
 ...
> > 
> > 
> > #e.g. 
> > 
> > 
> > df.prop
> > 
> > 
> > id a b c sum 
> > 1 x01 0.33 0.66 NA 3
> > 2 x02 0.22 0.44 0.33 9
> > 3 x03 NA 0.4 0.6 15
> > 4 x04 0.16 0.33 0.5 24
> > 5 x05 0.33 0.66 NA 15
> > 6 x06 1 NA NA 6
> > 
>
 > #and then calculate a rowsum, were each column is weighed by its 
associated factor in the vector "w", i.e. all entries in column df$a 
should be weighed by the factor 10.5, df$b by 9 and df$c by 12.8 and 
then summed up to a weighed rowsum (wrowsum=10.5*0.33+9*0.66).
> > 
>
 > Any suggestions how to achieve this in a simple way with 
dataframes that have 9000 rows and 44 columns (so I cannot do this row 
by row) - sorry, if this is to easy a question.
> > 
> > Thank you very much in advance!
> > 
> > Best wishes
> > 
> > Alain
> > [[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.
> > 
> 
> 
> -- 
> Eik Vettorazzi
> 
> Department of Medical Biometry and Epidemiology
> University Medical Center Hamburg-Eppendorf
> 
> Martinistr. 52
> 20246 Hamburg
> 
> T ++49/40/7410-58243
> F ++49/40/7410-57790
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> 
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