sjaffe wrote:
I'm sure I can put this together from the various 'apply's and split, but I
wonder if anyone has a quick incantation:
E.g. I can do tapply( data, groups, mean)
but how can I do something like: tapply( list(data,weights), groups,
weighted.mean ) ?
(or: mapply is to sapply as ? is to tapply )
Thanks for your help.
coef(lm(data ~ -1 + as.factor(groups), weights=weights))
Not the fastest, but IMO more comprehensible than the constructions
involving anonymous functions.
J. R. M. Hosking
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