Someone forgot drop=FALSE was needed. Fixed in R-patched.
BTW, calling an object `data' is not a good idea.
On Fri, 14 May 2004, Philippe Hupé wrote:
> Hi,
>
> I am trying to do the following aggregation :
>
>
> data <- data.frame(a=rep(2,10),b=rep("a",10))
> aggregate(data$a, by=list(a1=data$a, b1=data$b), NROW)
>
> but I have the following error message
>
>
> Error in "names<-.default"(`*tmp*`, value = c(names(by), names(x))) :
> names attribute [3] must be the same length as the vector [2]
> In addition: Warning message:
> row names were found from a short variable and have been discarded in:
> data.frame(w, lapply(y, unlist, use.names = FALSE))
>
> It works if there are more than 2 modalities in data$b. I can test if
> there is only one modality of course but there is no reason for the
> function not working in this particular case.
>
>
> I use R 1.9.0 under Solaris
>
>
--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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