I don't get the point. ?by says:
FUN a function to be applied to data frame subsets of data.
It doesn't say FUN can be a character, and by(iris, iris$Species, summary)
works as expected.
Andy
> From: Gabor Grothendieck
>
> I noticed that, unlike similar functions, 'by' does not use
> match.fun, e.g.
>
> > by(iris, iris$Species, "summary")
> Error in FUN(X[[1]], ...) : couldn't find function "FUN"
>
> The 'by' code should have an initial line of:
>
> FUN <- match.fun(FUN)
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel
>
>
>