[R] tapply for function taking of >1 argument?

[hadley wickham]

On Wed, Feb 3, 2010 at 11:06 AM, David Freedman <3.14david at gmail.com> wrote:
>
> also,
>
> library(plyr)
> ddply(d,~grp,function(df) weighted.mean(df$x,df$w))

Or

ddply(d, "grp", summarise, mean = weighted.mean(x, w))

which is convenient if you want more than one output

Hadley



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