[R] weighted mean by week

[Dimitri Liakhovitski]

Thanks a lot, David.
Indeed, it's much shorter.
Unfortunately, in my real task I am dozens and dozens of variables
like var1 and var2 so that manually specifying things like in
"m1=weighted.mean(var1,myweight)" would take a lot of code and a very
long time.
Dimitri

On Tue, Jul 17, 2012 at 6:34 PM, David Freedman <dxf1 at cdc.gov> wrote:
> The plyr package is very helpful for this:
>
> library(plyr)
> ddply(x ,.(myweek), summarize, m1=weighted.mean(var1,myweight),
> m2=weighted.mean(var2,myweight))
>
>
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-- 
Dimitri Liakhovitski
marketfusionanalytics.com