Re: [R] subtotal, submean, aggregate

From: Gabor Grothendieck <ggrothendieck_at_gmail.com>
Date: Mon 27 Feb 2006 - 01:08:31 EST

Create another variable that gives the run number and aggregate on both the habitat and run number removing the run number after aggregating:

runno <- cumsum(c(TRUE, diff(as.numeric(transect[,2])) !=0)) aggregate(transect[,1], list(obs = transect[,2], runno = runno), sum)[,-2]

This does not give the same as your example but I think there are some errors in your example output.

On 2/26/06, Patrick Giraudoux <patrick.giraudoux@univ-fcomte.fr> wrote:
> Dear All,
>
> I would like to make partial sums (or means or any other function) of
> the values in intervals along a sequence (spatial transect) where groups
> are defined.
>
> For instance:
>
> habitats<-rep(c("meadow","forest","meadow","pasture"),c(10,5,12,6))
> observations<-rpois(length(habitats),2)
> transect<-data.frame(observations=observations,habitats=habitats)
>
> aggregate() is not suitable for my purpose because I want a result
> respecting the order of the habitats encountered although they may have
> the same name (and not pooling each group on each level of the factor
> created). For instance, the output of the ideal function
> mynicefunction() would be something as:
>
> mynicefunction(transect$observations, by=list(transect$habitats),sum)
> meadow 16
> forest 9
> meadow 21
> pasture 17
>
> and not
>
> aggregate(transect$observations,by=list(transect$habitats),sum)
> Group.1 x
> 1 forest 9
> 2 meadow 37
> 3 pasture 17
>
> Did anybody hear about such a function already written in R? If no, any
> idea to make it simple and elegant to write?
>
> Cheers,
>
> Patrick Giraudoux
>
> ______________________________________________
> 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
>



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 Mon Feb 27 01:18:04 2006

This archive was generated by hypermail 2.1.8 : Fri 03 Mar 2006 - 03:42:45 EST